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  • trying to override getView in a SimpleCursorAdapter gives NullPointerException

    - by Dimitry Hristov
    Would very much appreciate any help or hint on were to go next. I'm trying to change the content of a row in ListView programmatically. In one row there are 3 TextView and a ProgressBar. I want to animate the ProgressBar if the 'result' column of the current row is zero. After reading some tutorials and docs, I came to the conclusion that LayoutInflater has to be used and getView() - overriden. Maybe I am wrong on this. If I return row = inflater.inflate(R.layout.row, null); from the function, it gives NullPointerException. Here is the code: private final class mySimpleCursorAdapter extends SimpleCursorAdapter { private Cursor localCursor; private Context localContext; public mySimpleCursorAdapter(Context context, int layout, Cursor c, String[] from, int[] to) { super(context, layout, c, from, to); this.localCursor = c; this.localContext = context; } /** * 1. ListView asks adapter "give me a view" (getView) for each item of the list * 2. A new View is returned and displayed */ public View getView(int position, View convertView, ViewGroup parent) { View row = super.getView(position, convertView, parent); LayoutInflater inflater = (LayoutInflater)localContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE); String result = localCursor.getString(2); int resInt = Integer.parseInt(result); Log.d(TAG, "row " + row); // if 'result' column form the TABLE is 0, do something useful: if(resInt == 0) { ProgressBar progress = (ProgressBar) row.findViewById(R.id.update_progress); progress.setIndeterminate(true); TextView edit1 = (TextView)row.findViewById(R.id.row_id); TextView edit2 = (TextView)row.findViewById(R.id.request); TextView edit3 = (TextView)row.findViewById(R.id.result); edit1.setText("1"); edit2.setText("2"); edit3.setText("3"); row = inflater.inflate(R.layout.row, null); } return row; } here is the Stack Trace: 03-08 03:15:29.639: ERROR/AndroidRuntime(619): java.lang.NullPointerException 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.SimpleCursorAdapter.bindView(SimpleCursorAdapter.java:149) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.CursorAdapter.getView(CursorAdapter.java:186) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at com.dhristov.test1.test1$mySimpleCursorAdapter.getView(test1.java:105) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.AbsListView.obtainView(AbsListView.java:1256) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.ListView.makeAndAddView(ListView.java:1668) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.ListView.fillDown(ListView.java:637) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.ListView.fillSpecific(ListView.java:1224) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.ListView.layoutChildren(ListView.java:1499) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.AbsListView.onLayout(AbsListView.java:1113) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.view.View.layout(View.java:6830) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.LinearLayout.onLayout(LinearLayout.java:918) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.view.View.layout(View.java:6830) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.LinearLayout.onLayout(LinearLayout.java:918) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.view.View.layout(View.java:6830) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.view.View.layout(View.java:6830) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1119) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:998) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.LinearLayout.onLayout(LinearLayout.java:918) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.view.View.layout(View.java:6830) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.widget.FrameLayout.onLayout(FrameLayout.java:333) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.view.View.layout(View.java:6830) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.view.ViewRoot.performTraversals(ViewRoot.java:996) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.view.ViewRoot.handleMessage(ViewRoot.java:1633) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.os.Handler.dispatchMessage(Handler.java:99) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.os.Looper.loop(Looper.java:123) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at android.app.ActivityThread.main(ActivityThread.java:4363) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at java.lang.reflect.Method.invokeNative(Native Method) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at java.lang.reflect.Method.invoke(Method.java:521) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 03-08 03:15:29.639: ERROR/AndroidRuntime(619): at dalvik.system.NativeStart.main(Native Method)

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  • Loading FireMonkey style resourses with RTTI

    - by HeMet
    I am trying to write class that inherits from FMX TStyledControl. When style is updated it loads style resource objects to cache. I created project group for package with custom controls and test FMX HD project as it describes in Delphi help. After installing package and placing TsgSlideHost on the test form I run test app. It’s work well, but when I close it and try to rebuild package RAD Studio says “Error in rtl160.bpl” or “invalid pointer operation”. It seems what problem in LoadToCacheIfNeeded procedure from TsgStyledControl, but I’m not understand why. Is there any restriction on using RTTI with FMX styles or anything? TsgStyledControl sources: unit SlideGUI.TsgStyledControl; interface uses System.SysUtils, System.Classes, System.Types, FMX.Types, FMX.Layouts, FMX.Objects, FMX.Effects, System.UITypes, FMX.Ani, System.Rtti, System.TypInfo; type TCachedAttribute = class(TCustomAttribute) private fStyleName: string; public constructor Create(const aStyleName: string); property StyleName: string read fStyleName; end; TsgStyledControl = class(TStyledControl) private procedure CacheStyleObjects; procedure LoadToCacheIfNeeded(aField: TRttiField); protected function FindStyleResourceAs<T: class>(const AStyleLookup: string): T; function GetStyleName: string; virtual; abstract; function GetStyleObject: TControl; override; public procedure ApplyStyle; override; published { Published declarations } end; implementation { TsgStyledControl } procedure TsgStyledControl.ApplyStyle; begin inherited; CacheStyleObjects; end; procedure TsgStyledControl.CacheStyleObjects; var ctx: TRttiContext; typ: TRttiType; fld: TRttiField; begin ctx := TRttiContext.Create; try typ := ctx.GetType(Self.ClassType); for fld in typ.GetFields do LoadFromCacheIfNeeded(fld); finally ctx.Free end; end; function TsgStyledControl.FindStyleResourceAs<T>(const AStyleLookup: string): T; var fmxObj: TFmxObject; begin fmxObj := FindStyleResource(AStyleLookup); if Assigned(fmxObj) and (fmxObj is T) then Result := fmxObj as T else Result := nil; end; function TsgStyledControl.GetStyleObject: TControl; var S: TResourceStream; begin if (FStyleLookup = '') then begin if FindRCData(HInstance, GetStyleName) then begin S := TResourceStream.Create(HInstance, GetStyleName, RT_RCDATA); try Result := TControl(CreateObjectFromStream(nil, S)); Exit; finally S.Free; end; end; end; Result := inherited GetStyleObject; end; procedure TsgStyledControl.LoadToCacheIfNeeded(aField: TRttiField); var attr: TCustomAttribute; styleName: string; styleObj: TFmxObject; val: TValue; begin for attr in aField.GetAttributes do begin if attr is TCachedAttribute then begin styleName := TCachedAttribute(attr).StyleName; if styleName <> '' then begin styleObj := FindStyleResource(styleName); val := TValue.From<TFmxObject>(styleObj); aField.SetValue(Self, val); end; end; end; end; { TCachedAttribute } constructor TCachedAttribute.Create(const aStyleName: string); begin fStyleName := aStyleName; end; end. Using of TsgStyledControl: type TsgSlideHost = class(TsgStyledControl) private [TCached('SlideHost')] fSlideHost: TLayout; [TCached('SideMenu')] fSideMenuLyt: TLayout; [TCached('SlideContainer')] fSlideContainer: TLayout; fSideMenu: IsgSideMenu; procedure ReapplyProps; procedure SetSideMenu(const Value: IsgSideMenu); protected function GetStyleName: string; override; function GetStyleObject: TControl; override; procedure UpdateSideMenuLyt; public constructor Create(AOwner: TComponent); override; procedure ApplyStyle; override; published property SideMenu: IsgSideMenu read fSideMenu write SetSideMenu; end;

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  • Silverlight Chat WrapPanel Crash / Bug

    - by Matt
    I've been given the task to create a simple Silverlight chat box for two people. My control must adhere to the following requirements Scrollable Text must wrap if it's too long When a new item / message is added it must scroll that item into view Now I've successfully made a usercontrol to meet these requirements, but I've run into a possible bug / crash that I can't for the life of me fix. I'm looking for either a fix to the bug, or a different approach to creating a scrollable chat control. Here's the code I've been using. We'll start with my XAML for the chat window <ListBox x:Name="lbChatHistory" Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2" ScrollViewer.VerticalScrollBarVisibility="Visible" ScrollViewer.HorizontalScrollBarVisibility="Disabled" > <ListBox.ItemTemplate> <DataTemplate> <Grid Background="Beige"> <Grid.ColumnDefinitions> <ColumnDefinition Width="70"></ColumnDefinition> <ColumnDefinition Width="Auto"></ColumnDefinition> </Grid.ColumnDefinitions> <TextBlock x:Name="lblPlayer" Foreground="{Binding ForeColor}" Text="{Binding Player}" Grid.Column="0"></TextBlock> <ContentPresenter Grid.Column="1" Width="200" Content="{Binding Message}" /> </Grid> </DataTemplate> </ListBox.ItemTemplate> </ListBox> The idea is to add a new Item to the listbox. The Item (as layed out in the XAML) is a simple 2 column grid. One column for the username, and one column for the message. Now the "items" that I add to the ListBox is a custom class. It has three properties (Player, ForeColor, and Message) that I using binding on within my XAML Player is a string of the current user to display. ForeColor is just a foreground color preference. It helps distinguish the difference between messages. Message is a WrapPanel. I programmatically break the supplied string on the white space for each word. Then for each word, I add a new TextBlock element to the WrapPanel Here is the custom class. public class ChatMessage :DependencyObject, INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public static DependencyProperty PlayerProperty = DependencyProperty.Register( "Player", typeof( string ), typeof( ChatMessage ), new PropertyMetadata( new PropertyChangedCallback( OnPlayerPropertyChanged ) ) ); public static DependencyProperty MessageProperty = DependencyProperty.Register( "Message", typeof( WrapPanel ), typeof( ChatMessage ), new PropertyMetadata( new PropertyChangedCallback( OnMessagePropertyChanged ) ) ); public static DependencyProperty ForeColorProperty = DependencyProperty.Register( "ForeColor", typeof( SolidColorBrush ), typeof( ChatMessage ), new PropertyMetadata( new PropertyChangedCallback( OnForeColorPropertyChanged ) ) ); private static void OnForeColorPropertyChanged( DependencyObject d, DependencyPropertyChangedEventArgs e ) { ChatMessage c = d as ChatMessage; c.ForeColor = ( SolidColorBrush ) e.NewValue; } public ChatMessage() { Message = new WrapPanel(); ForeColor = new SolidColorBrush( Colors.White ); } private static void OnMessagePropertyChanged( DependencyObject d, DependencyPropertyChangedEventArgs e ) { ChatMessage c = d as ChatMessage; c.Message = ( WrapPanel ) e.NewValue; } private static void OnPlayerPropertyChanged( DependencyObject d, DependencyPropertyChangedEventArgs e ) { ChatMessage c = d as ChatMessage; c.Player = e.NewValue.ToString(); } public SolidColorBrush ForeColor { get { return ( SolidColorBrush ) GetValue( ForeColorProperty ); } set { SetValue( ForeColorProperty, value ); if(PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs( "ForeColor" )); } } public string Player { get { return ( string ) GetValue( PlayerProperty ); } set { SetValue( PlayerProperty, value ); if ( PropertyChanged != null ) PropertyChanged( this, new PropertyChangedEventArgs( "Player" ) ); } } public WrapPanel Message { get { return ( WrapPanel ) GetValue( MessageProperty ); } set { SetValue( MessageProperty, value ); if ( PropertyChanged != null ) PropertyChanged( this, new PropertyChangedEventArgs( "Message" ) ); } } } Lastly I add my items to the ListBox. Here's the simple method. It takes the above ChatMessage class as a parameter public void AddChatItem( ChatMessage msg ) { lbChatHistory.Items.Add( msg ); lbChatHistory.ScrollIntoView( msg ); } Now I've tested this and it all works. The problem I'm getting is when I use the scroll bar. You can scroll down using the side scroll bar or arrow keys, but when you scroll up Silverlight crashes. FireBug returns a ManagedRuntimeError #4004 with a XamlParseException. I'm soo close to having this control work, I can taste it! Any thoughts on what I should do or change? Is there a better approach than the one I've taken? Thanks in advance. UPDATE I've found an alternative solution using a ScrollViewer and an ItemsControl instead of a ListBox control. For the most part it's stable.

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  • Windows Phone 7: Building a simple dictionary web client

    - by TechTwaddle
    Like I mentioned in this post a while back, I came across a dictionary web service called Aonaware that serves up word definitions from various dictionaries and is really easy to use. The services page on their website, http://services.aonaware.com/DictService/DictService.asmx, lists all the operations that are supported by the dictionary service. Here they are, Word Dictionary Web Service The following operations are supported. For a formal definition, please review the Service Description. Define Define given word, returning definitions from all dictionaries DefineInDict Define given word, returning definitions from specified dictionary DictionaryInfo Show information about the specified dictionary DictionaryList Returns a list of available dictionaries DictionaryListExtended Returns a list of advanced dictionaries (e.g. translating dictionaries) Match Look for matching words in all dictionaries using the given strategy MatchInDict Look for matching words in the specified dictionary using the given strategy ServerInfo Show remote server information StrategyList Return list of all available strategies on the server Follow the links above to get more information on each API. In this post we will be building a simple windows phone 7 client which uses this service to get word definitions for words entered by the user. The application will also allow the user to select a dictionary from all the available ones and look up the word definition in that dictionary. So of all the apis above we will be using only two, DictionaryList() to get a list of all supported dictionaries and DefineInDict() to get the word definition from a particular dictionary. Before we get started, a note to you all; I would have liked to implement this application using concepts from data binding, item templates, data templates etc. I have a basic understanding of what they are but, being a beginner, I am not very comfortable with those topics yet so I didn’t use them. I thought I’ll get this version out of the way and maybe in the next version I could give those a try. A somewhat scary mock-up of the what the final application will look like, Select Dictionary is a list picker control from the silverlight toolkit (you need to download and install the toolkit if you haven’t already). Below it is a textbox where the user can enter words to look up and a button beside it to fetch the word definition when clicked. Finally we have a textblock which occupies the remaining area and displays the word definition from the selected dictionary. Create a silverlight application for windows phone 7, AonawareDictionaryClient, and add references to the silverlight toolkit and the web service. From the solution explorer right on References and select Microsoft.Phone.Controls.Toolkit from under the .NET tab, Next, add a reference to the web service. Again right click on References and this time select Add Service Reference In the resulting dialog paste the service url in the Address field and press go, (url –> http://services.aonaware.com/DictService/DictService.asmx) once the service is discovered, provide a name for the NameSpace, in this case I’ve called it AonawareDictionaryService. Press OK. You can now use the classes and functions that are generated in the AonawareDictionaryClient.AonawareDictionaryService namespace. Let’s get the UI done now. In MainPage.xaml add a namespace declaration to use the toolkit controls, xmlns:toolkit="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls.Toolkit" the content of LayoutRoot is changed as follows, (sorry, no syntax highlighting in this post) <StackPanel x:Name="TitlePanel" Grid.Row="0" Margin="12,5,0,5">     <TextBlock x:Name="ApplicationTitle" Text="AONAWARE DICTIONARY CLIENT" Style="{StaticResource PhoneTextNormalStyle}"/>     <!--<TextBlock x:Name="PageTitle" Text="page name" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>--> </StackPanel> <!--ContentPanel - place additional content here--> <Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">     <Grid.RowDefinitions>         <RowDefinition Height="Auto"/>         <RowDefinition Height="Auto"/>         <RowDefinition Height="*"/>     </Grid.RowDefinitions>     <toolkit:ListPicker Grid.Column="1" x:Name="listPickerDictionaryList"                         Header="Select Dictionary :">     </toolkit:ListPicker>     <Grid Grid.Row="1" Margin="0,5,0,0">         <Grid.ColumnDefinitions>             <ColumnDefinition Width="*"/>             <ColumnDefinition Width="Auto" />         </Grid.ColumnDefinitions>         <TextBox x:Name="txtboxInputWord" Grid.Column="0" GotFocus="OnTextboxInputWordGotFocus" />         <Button x:Name="btnGo" Grid.Column="1" Click="OnButtonGoClick" >             <Button.Content>                 <Image Source="/images/button-go.png"/>             </Button.Content>         </Button>     </Grid>     <ScrollViewer Grid.Row="2" x:Name="scrollViewer">         <TextBlock  Margin="12,5,12,5"  x:Name="txtBlockWordMeaning" HorizontalAlignment="Stretch"                    VerticalAlignment="Stretch" TextWrapping="Wrap"                    FontSize="26" />     </ScrollViewer> </Grid> I have commented out the PageTitle as it occupies too much valuable space, and the ContentPanel is changed to contain three rows. First row contains the list picker control, second row contains the textbox and the button, and the third row contains a textblock within a scroll viewer. The designer will now be showing the final ui, Now go to MainPage.xaml.cs, and add the following namespace declarations, using Microsoft.Phone.Controls; using AonawareDictionaryClient.AonawareDictionaryService; using System.IO.IsolatedStorage; A class called DictServiceSoapClient would have been created for you in the background when you added a reference to the web service. This class functions as a wrapper to the services exported by the web service. All the web service functions that we saw at the start can be access through this class, or more precisely through an object of this class. Create a data member of type DictServiceSoapClient in the Mainpage class, and a function which initializes it, DictServiceSoapClient DictSvcClient = null; private DictServiceSoapClient GetDictServiceSoapClient() {     if (null == DictSvcClient)     {         DictSvcClient = new DictServiceSoapClient();     }     return DictSvcClient; } We have two major tasks remaining. First, when the application loads we need to populate the list picker with all the supported dictionaries and second, when the user enters a word and clicks on the arrow button we need to fetch the word’s meaning. Populating the List Picker In the OnNavigatingTo event of the MainPage, we call the DictionaryList() api. This can also be done in the OnLoading event handler of the MainPage; not sure if one has an advantage over the other. Here’s the code for OnNavigatedTo, protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e) {     DictServiceSoapClient client = GetDictServiceSoapClient();     client.DictionaryListCompleted += new EventHandler<DictionaryListCompletedEventArgs>(OnGetDictionaryListCompleted);     client.DictionaryListAsync();     base.OnNavigatedTo(e); } Windows Phone 7 supports only async calls to web services. When we added a reference to the dictionary service, asynchronous versions of all the functions were generated automatically. So in the above function we register a handler to the DictionaryListCompleted event which will occur when the call to DictionaryList() gets a response from the server. Then we call the DictionaryListAsynch() function which is the async version of the DictionaryList() api. The result of this api will be sent to the handler OnGetDictionaryListCompleted(), void OnGetDictionaryListCompleted(object sender, DictionaryListCompletedEventArgs e) {     IsolatedStorageSettings settings = IsolatedStorageSettings.ApplicationSettings;     Dictionary[] listOfDictionaries;     if (e.Error == null)     {         listOfDictionaries = e.Result;         PopulateListPicker(listOfDictionaries, settings);     }     else if (settings.Contains("SavedDictionaryList"))     {         listOfDictionaries = settings["SavedDictionaryList"] as Dictionary[];         PopulateListPicker(listOfDictionaries, settings);     }     else     {         MessageBoxResult res = MessageBox.Show("An error occured while retrieving dictionary list, do you want to try again?", "Error", MessageBoxButton.OKCancel);         if (MessageBoxResult.OK == res)         {             GetDictServiceSoapClient().DictionaryListAsync();         }     }     settings.Save(); } I have used IsolatedStorageSettings to store a few things; the entire dictionary list and the dictionary that is selected when the user exits the application, so that the next time when the user starts the application the current dictionary is set to the last selected value. First we check if the api returned any error, if the error object is null e.Result will contain the list (actually array) of Dictionary type objects. If there was an error, we check the isolated storage settings to see if there is a dictionary list stored from a previous instance of the application and if so, we populate the list picker based on this saved list. Note that in this case there are chances that the dictionary list might be out of date if there have been changes on the server. Finally, if none of these cases are true, we display an error message to the user and try to fetch the list again. PopulateListPicker() is passed the array of Dictionary objects and the settings object as well, void PopulateListPicker(Dictionary[] listOfDictionaries, IsolatedStorageSettings settings) {     listPickerDictionaryList.Items.Clear();     foreach (Dictionary dictionary in listOfDictionaries)     {         listPickerDictionaryList.Items.Add(dictionary.Name);     }     settings["SavedDictionaryList"] = listOfDictionaries;     string savedDictionaryName;     if (settings.Contains("SavedDictionary"))     {         savedDictionaryName = settings["SavedDictionary"] as string;     }     else     {         savedDictionaryName = "WordNet (r) 2.0"; //default dictionary, wordnet     }     foreach (string dictName in listPickerDictionaryList.Items)     {         if (dictName == savedDictionaryName)         {             listPickerDictionaryList.SelectedItem = dictName;             break;         }     }     settings["SavedDictionary"] = listPickerDictionaryList.SelectedItem as string; } We first clear all the items from the list picker, add the dictionary names from the array and then create a key in the settings called SavedDictionaryList and store the dictionary list in it. We then check if there is saved dictionary available from a previous instance, if there is, we set it as the selected item in the list picker. And if not, we set “WordNet ® 2.0” as the default dictionary. Before returning, we save the selected dictionary in the “SavedDictionary” key of the isolated storage settings. Fetching word definitions Getting this part done is very similar to the above code. We get the input word from the textbox, call into DefineInDictAsync() to fetch the definition and when DefineInDictAsync completes, we get the result and display it in the textblock. Here is the handler for the button click, private void OnButtonGoClick(object sender, RoutedEventArgs e) {     txtBlockWordMeaning.Text = "Please wait..";     IsolatedStorageSettings settings = IsolatedStorageSettings.ApplicationSettings;     if (txtboxInputWord.Text.Trim().Length <= 0)     {         MessageBox.Show("Please enter a word in the textbox and press 'Go'");     }     else     {         Dictionary[] listOfDictionaries = settings["SavedDictionaryList"] as Dictionary[];         string selectedDictionary = listPickerDictionaryList.SelectedItem.ToString();         string dictId = "wn"; //default dictionary is wordnet (wn is the dict id)         foreach (Dictionary dict in listOfDictionaries)         {             if (dict.Name == selectedDictionary)             {                 dictId = dict.Id;                 break;             }         }         DictServiceSoapClient client = GetDictServiceSoapClient();         client.DefineInDictCompleted += new EventHandler<DefineInDictCompletedEventArgs>(OnDefineInDictCompleted);         client.DefineInDictAsync(dictId, txtboxInputWord.Text.Trim());     } } We validate the input and then select the dictionary id based on the currently selected dictionary. We need the dictionary id because the api DefineInDict() expects the dictionary identifier and not the dictionary name. We could very well have stored the dictionary id in isolated storage settings too. Again, same as before, we register a event handler for the DefineInDictCompleted event and call the DefineInDictAsync() method passing in the dictionary id and the input word. void OnDefineInDictCompleted(object sender, DefineInDictCompletedEventArgs e) {     WordDefinition wd = e.Result;     scrollViewer.ScrollToVerticalOffset(0.0f);     if (wd.Definitions.Length == 0)     {         txtBlockWordMeaning.Text = String.Format("No definitions were found for '{0}' in '{1}'", txtboxInputWord.Text.Trim(), listPickerDictionaryList.SelectedItem.ToString().Trim());     }     else     {         foreach (Definition def in wd.Definitions)         {             string str = def.WordDefinition;             str = str.Replace("  ", " "); //some formatting             txtBlockWordMeaning.Text = str;         }     } } When the api completes, e.Result will contain a WordDefnition object. This class is also generated in the background while adding the service reference. We check the word definitions within this class to see if any results were returned, if not, we display a message to the user in the textblock. If a definition was found the text on the textblock is set to display the definition of the word. Adding final touches, we now need to save the current dictionary when the application exits. A small but useful thing is selecting the entire word in the input textbox when the user selects it. This makes sure that if the user has looked up a definition for a really long word, he doesn’t have to press ‘clear’ too many times to enter the next word, protected override void OnNavigatingFrom(System.Windows.Navigation.NavigatingCancelEventArgs e) {     IsolatedStorageSettings settings = IsolatedStorageSettings.ApplicationSettings;     settings["SavedDictionary"] = listPickerDictionaryList.SelectedItem as string;     settings.Save();     base.OnNavigatingFrom(e); } private void OnTextboxInputWordGotFocus(object sender, RoutedEventArgs e) {     TextBox txtbox = sender as TextBox;     if (txtbox.Text.Trim().Length > 0)     {         txtbox.SelectionStart = 0;         txtbox.SelectionLength = txtbox.Text.Length;     } } OnNavigatingFrom() is called whenever you navigate away from the MainPage, since our application contains only one page that would mean that it is exiting. I leave you with a short video of the application in action, but before that if you have any suggestions on how to make the code better and improve it please do leave a comment. Until next time…

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  • CodePlex Daily Summary for Tuesday, May 31, 2011

    CodePlex Daily Summary for Tuesday, May 31, 2011Popular ReleasesNearforums - ASP.NET MVC forum engine: Nearforums v6.0: Version 6.0 of Nearforums, the ASP.NET MVC Forum Engine, containing new features: Authentication using Membership Provider for SQL Server and MySql Spam prevention: Flood Control Moderation: Flag messages Content management: Pages: Create pages (about us/contact/texts) through web administration Allow nearforums to run as an IIS subapp Migrated Facebook Connect to OAuth 2.0 Visit the project Roadmap for more details.NetOffice - The easiest way to use Office in .NET: NetOffice Release 0.8b: Changes: - fix critical issue 15922(AccessViolationException) once and for all update is strongly recommended Includes: - Runtime Binaries and Source Code for .NET Framework:......v2.0, v3.0, v3.5, v4.0 - Tutorials in C# and VB.Net:..............................................................COM Proxy Management, Events, etc. - Examples in C# and VB.Net:............................................................Excel, Word, Outlook, PowerPoint, Access - COMAddin Examples in C# and VB....Facebook Graph Toolkit: Facebook Graph Toolkit 1.5.4186: Updates the API in response to Facebook's recent change of policy: All Graph Api accessing feeds or posts must provide a AccessToken.SharePoint Farm Poster: SharePoint Farm Poster: SharePoint Farm Poster is generated by a PowerShell Script. Run this script under the Farm Admin Account. After downloading, unblock the file in the Property Window. Current version is beta : v0.3.0VCC: Latest build, v2.1.40530.0: Automatic drop of latest buildServiio for Windows Home Server: Beta Release 0.5.2.0: Ready for widespread beta. Synchronized build number to Serviio version to avoid confusion.AcDown????? - Anime&Comic Downloader: AcDown????? v3.0 Beta4: ??AcDown?????????????,??????????????,????、????。?????Acfun????? ????32??64? Windows XP/Vista/7 ????????????? ??:????????Windows XP???,?????????.NET Framework 2.0???(x86)?.NET Framework 2.0???(x64),?????"?????????"??? ??v3.0 Beta4 2011-5-31?? ???Bilibili.us????? ???? ?? ???"????" ???Bilibili.us??? ??????? ?? ??????? ?? ???????? ?? ?? ???Bilibili.us?????(??????????????????) ??????(6.cn)?????(????) ?? ?????Acfun?????????? ?????????????? ???QQ???????? ????????????Discussion...Terraria Map Generator: TerrariaMapTool 1.0.0.2 Beta: Version 1.0.0.2 Beta Release - Now has a Gui - Draws backgrounds (May still not be exact) - Hopefully fixed support on DirectX 9 machine.CodeCopy Auto Code Converter: Code Copy v0.1: Full add-in, setup project source code and setup fileEnhSim: EnhSim 2.4.5 ALPHA: 2.4.5 ALPHAThis release supports WoW patch 4.1 at level 85 To use this release, you must have the Microsoft Visual C++ 2010 Redistributable Package installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=A7B7A05E-6DE6-4D3A-A423-37BF0912DB84 To use the GUI you must have the .NET 4.0 Framework installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9cfb2d51-5ff4-4491-b0e5-b386f32c0992 - Added in the T12 s...TerrariViewer: TerrariViewer v2.4.1: Added Piggy Bank editor and fixed some minor bugs.Kooboo CMS: Kooboo CMS 3.02: What is new in kooboo cms 3.02 The most important updates of this version is the Kooboo site builder, an unique and creative web design tool, design an professional website and export to Kooboo CMS. See: http://www.sitekin.com Add Version contorl on View, Layout and other elements. Add user CMS language selection, user can select a language to use on their CMS backend. Add User profile provider, you can use now stop website user information on a SQL database. Previously it stored on XML...mojoPortal: 2.3.6.6: see release notes on mojoportal.com http://www.mojoportal.com/mojoportal-2366-released Note that we have separate deployment packages for .NET 3.5 and .NET 4.0 The deployment package downloads on this page are pre-compiled and ready for production deployment, they contain no C# source code. To download the source code see the Source Code Tab I recommend getting the latest source code using TortoiseHG, you can get the source code corresponding to this release here.Terraria World Creator: Terraria World Creator: Version 1.01 Fixed a bug that would cause the application to crash. Re-named the Application.VidCoder: 0.9.0: New startup UI for one-click scanning of discs or opening a file/folder. New seek bar on the preview window to make switching previews easier (you can click anywhere on the bar). Added gradient backgrounds to the main window to visually group the sections. Added Open Video File and Open Video Folder options to the File menu. Moved preview button to be in line with the other control buttons. Fixed settings getting in a weird state if they were saved without an output folder being chos...General Media Access WebService: 0.2.0.0 Beta: Updated GMA release with sorting/ordering mechanisms. Several bug fixes.Microsoft All-In-One Code Framework - a centralized code sample library: All-In-One Code Framework 2011-05-26: Alternatively, you can install Sample Browser or Sample Browser VS extension, and download the code samples from Sample Browser. Improved and Newly Added Examples:For an up-to-date code sample index, please refer to All-In-One Code Framework Sample Catalog. NEW Samples for Dynamics Sample Description Owner CSDynamicsNAVWebServices The code sample shows syntax for calling Dynamics NAV Web Services. Lars Lohndorf-Larsen NEW Samples for WPF Sample Description Owner CSWPFDataGridCustomS...Terraria World Viewer: Version 1.1: Update May 26th Added Chest Filtering, this allows chests only containing certain items to have their symbol drawn. (Its under advanced settings tab) GUI elements (checkboxes/etc) are persistant between uses of the application Beta Worlds (i.e. Release #38) will work properly Symbols can be enabled or disabled on a per symbol basis Chest Information tab which is just a dump of the current chest information Meterorite is now visible as a bright magenta pink Application defaults to ...MVC Controls Toolkit: Mvc Controls Toolkit 1.1 RC: *Added: Compatibility with jQuery 1.6.1 Rendering of enumerables with images and/or customizable strings improved the client side tempate engine added new parameters to the template definition binding all new knockout bindings helpers have been fully implemented added a new overload for defining the client-side ViewModel The SetTme method has the option to store the theme in a permanent cookie If no CSS class is provided for the watermark of a TypedTextBox the watermark class of the current t...patterns & practices: Project Silk: Project Silk - Documentation Only Drop - May 24: To get the latest code, please see the previous drop here. Guidance Chapters Ready for Review The following chapters (provided in CHM or PDF format) are ready for community review. Our team very much appreciates your feedback and technical review. All documentation feedback should be posted in the Issue Tracker; if required, a document can be attached along with the feedback. Architecture jQuery UI Widgets Server-Side Implementation Security Unit Testing Web Applications Widget Q...New Projects#liveDB: liveDB is an in-memory database engine for Microsoft .NET providing full ACID support, lightning fast performance and offering a significant reduction of development and operational costs. liveDB is built on Live Domain Technology(TM).8 hours: 8hours Private studyABox2d: A port of Box 2d game engine doing it has an exercise to study how the game engine work.ADempiere.NET: If I have enough time and support I we will translate this into .NETAlmonaster: Almonaster is a turn-based multi-player war game. It is free for all players and comes with absolutely no warranty. The game is fully web-based and requires no downloads, Javascript, Java or ActiveX controls. ASPone API: ASPone partnerské API (aplikacní programové rozhraní) je rozhraní pro vytvorené a urcené pro partnery spolecnosti ASPone, s.r.o. Pomocí tohoto aplikacního rozhraní mužete zautomatizovat radu úkonu, které by pomocí webového rozhraní mohly být casove nárocnejší nebo vyžadují interakci cloveka. API umožnuje zautomatizovat radu úkonu souvisejících se správou domén, doménových kontaktu, webhostingu, databází, serveru a mnoha dalších. Pro zjednodušení práce s API jsou již pripraveni dva ukázkový...CodeCopy Auto Code Converter: This add-in project converts c# and vb.net codes in visual studio.drms: Data Resource Management SystemDrop Down CheckBoxList control (DropDownCheckBoxes): DropDownCheckBoxes is an ASP.NET server control directly inheriting standard ASP.NET CheckBoxList control and fully it supports parent's API (except members responsible for rendering and styling). Thus in most cases CheckBoxList control can be simply replaced with DropDownCheckBoxes with no need to change any data binding code or event handlers. In normal state the control is displayed as a select (DropDownList) control. Clicking the expand button shows a list with check boxes. When the se...Extended Registration module for Orchard CMS: This project has a dependency on the Contrib.Profile module. With this module enabled, users must fill out any parts you add to the User ContentItem in the Registration page. Ideal if you require additional information from your users.GreenWay: Car navigation softwareHost Profiles: Host Profiles is small tool to control, switch and management the hosts file of the computer. The hosts file is located in "c:\windows\system32\drivers\etc\hosts".HRM System MVVM sample code: This is the sample WPF MVVM application that i've described in my blog posts. I hope to give you a clear view of mvvm and other commonly used patterns.Mi Game Library: Ever wanted to store all the games you own into one place that you, could then later come see and search also with your own personal wish list!Micorrhiza: Micorrhiza is a client-server solution written in C# for voice- and video-communications between users in local and global networks.MPlayer.NET for Windows Forms & WPF: MPlayer.NET is a wrapper around MPlayer executable. It's developed on .NET platform and includes visual controls for both Windows Forms and WPF applications.MyGet - NuGet-as-a-Service: This project is the source for http://myget.org. MyGet offers you the possibility to create your own, private, filtered NuGet feed for use in the Visual Studio Package Manager. It can contain packages from the official NuGet feed as well as your private packages, hosted on MyGet.MZExtensions: A collection of handy C# Extension Methods.NCAds: NCadsNetSync: Universal file synchronization agent.OLE 1C7.7: OLE 1C7.7 ?????????? ??????? ??? ??????? ? 1?7.7 ????????? OLE ??????????.Pear 2.5: Pear 2.5 is a web browser which has MetroUI which is also known for WP7. Pear 2.5's graphics is totally made up with MetroUI and looks stunning when browse. This version has 3 builds - 2 alpha builds and 1 gamma delta (beta) build. It's developed in VB.NET which is the easiest.ProjectOne: ProjectOne is a Open Community Information Sharing Website regarding Realty as its primary source.russomi: russomiSopaco Server Foundation 1.x: The one earlier version of my server infrastructure(SSF, Sopaco Server Foundation 1.x, owned by ??)。 Network Layer Based On MINA, message meta in 1.x is hard coded to 6bytes message header like this struct NetworkMessageHeader { short msgId; int msgLength; } struct NetworkMTray Timer: A simple timer/stopwatch which runs fromt he system tray. I started it as a hobby learning project to understand the Win32 API. Now open sourcing it to get more inputs about the same, and at the same time it may prove helpful to othersVENSOFT DIPERCAX: Proyecto Final del Curso de Proyectos II de la Universidad Privada del NorteWindows Phone Blog Menu: A Silverlight navigation control that looks like a Windows Phone 7. The live tiles are links to websites. Use this control on your blog or website to show your love for WP7. It is a creative way to link to external sites you are interested in.

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  • Am I going about this the right way?

    - by Psytronic
    Hey Guys, I'm starting a WPF project, and just finished the base of the UI, it seems very convoluted though, so I'm not sure if I've gone around laying it out in the right way. I don't want to get to start developing the back-end and realise that I've done the front wrong, and make life harder for myself. Coming from a background of <DIV's and CSS to style this is a lot different, and really want to get it right from the start. Essentially it's a one week calendar (7 days, Mon-Sunday, defaulting to the current week.) Which will eventually link up to a DB and if I have an appointment for something on this day it will show it in the relevant day. I've opted for a Grid rather than ListView because of the way it will work I will not be binding the results to a collection or anything along those lines. Rather I will be filling out a Combo box within the canvas for each day (yet to be placed in the code) for each event and on selection it will show me further details. XAML: <Window x:Class="WOW_Widget.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:Extensions="clr-namespace:WOW_Widget" DataContext="{Binding RelativeSource={RelativeSource Self}}" Title="Window1" Height="239" Width="831" <Window.Resources <LinearGradientBrush x:Key="NormalBrush" StartPoint="0,0" EndPoint="0,1" <GradientBrush.GradientStops <GradientStopCollection <GradientStop Offset="1.0" Color="White"/ <GradientStop Offset="0.0" Color="LightSlateGray"/ </GradientStopCollection </GradientBrush.GradientStops </LinearGradientBrush <LinearGradientBrush x:Key="grdDayHeader" StartPoint="0,0" EndPoint="0,1" <GradientBrush.GradientStops <GradientStopCollection <GradientStop Offset="0.0" Color="Peru" / <GradientStop Offset="1.0" Color="White" / </GradientStopCollection </GradientBrush.GradientStops </LinearGradientBrush <LinearGradientBrush x:Key="grdToday" StartPoint="0,0" EndPoint="0,1" <GradientBrush.GradientStops <GradientStopCollection <GradientStop Offset="0.0" Color="LimeGreen"/ <GradientStop Offset="1.0" Color="DarkGreen" / </GradientStopCollection </GradientBrush.GradientStops </LinearGradientBrush <Style TargetType="{x:Type GridViewColumnHeader}" <Setter Property="Background" Value="Khaki" / </Style <Style x:Key="DayHeader" TargetType="{x:Type Label}" <Setter Property="Background" Value="{StaticResource grdDayHeader}" / <Setter Property="Width" Value="111" / <Setter Property="Height" Value="25" / <Setter Property="HorizontalContentAlignment" Value="Center" / </Style <Style x:Key="DayField" <Setter Property="Canvas.Width" Value="111" / <Setter Property="Canvas.Height" Value="60" / <Setter Property="Canvas.Background" Value="White" / </Style <Style x:Key="Today" <Setter Property="Canvas.Background" Value="{StaticResource grdToday}" / </Style <Style x:Key="CalendarColSpacer" <Setter Property="Canvas.Width" Value="1" / <Setter Property="Canvas.Background" Value="Black" / </Style <Style x:Key="CalendarRowSpacer" <Setter Property="Canvas.Height" Value="1" / <Setter Property="Canvas.Background" Value="Black" / </Style </Window.Resources <Grid Background="{StaticResource NormalBrush}" <Border BorderBrush="Black" BorderThickness="1" Width="785" Height="86" Margin="12,12,12,104" <Canvas Height="86" Width="785" VerticalAlignment="Top" <Grid <Grid.ColumnDefinitions <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / <ColumnDefinition / </Grid.ColumnDefinitions <Grid.RowDefinitions <RowDefinition / <RowDefinition / <RowDefinition / </Grid.RowDefinitions <Label Grid.Column="0" Grid.Row="0" Content="Monday" Style="{StaticResource DayHeader}" / <Canvas Grid.Column="1" Grid.RowSpan="3" Grid.Row="0" Style="{StaticResource CalendarColSpacer}" / <Label Grid.Column="2" Grid.Row="0" Content="Tuesday" Style="{StaticResource DayHeader}" / <Canvas Grid.Column="3" Grid.RowSpan="3" Grid.Row="0" Style="{StaticResource CalendarColSpacer}" / <Label Grid.Column="4" Grid.Row="0" Content="Wednesday" Style="{StaticResource DayHeader}" / <Canvas Grid.Column="5" Grid.RowSpan="3" Grid.Row="0" Style="{StaticResource CalendarColSpacer}" / <Label Grid.Column="6" Grid.Row="0" Content="Thursday" Style="{StaticResource DayHeader}" / <Canvas Grid.Column="7" Grid.RowSpan="3" Grid.Row="0" Style="{StaticResource CalendarColSpacer}" / <Label Grid.Column="8" Grid.Row="0" Content="Friday" Style="{StaticResource DayHeader}" / <Canvas Grid.Column="9" Grid.RowSpan="3" Grid.Row="0" Style="{StaticResource CalendarColSpacer}" / <Label Grid.Column="10" Grid.Row="0" Content="Saturday" Style="{StaticResource DayHeader}" / <Canvas Grid.Column="11" Grid.RowSpan="3" Grid.Row="0" Style="{StaticResource CalendarColSpacer}" / <Label Grid.Column="12" Grid.Row="0" Content="Sunday" Style="{StaticResource DayHeader}" / <Canvas Grid.Column="0" Grid.ColumnSpan="13" Grid.Row="1" Style="{StaticResource CalendarRowSpacer}" / <Canvas Grid.Column="0" Grid.Row="2" Margin="0" Style="{StaticResource DayField}" <Label Name="lblMondayDate" / </Canvas <Canvas Grid.Column="2" Grid.Row="2" Margin="0" Style="{StaticResource DayField}" <Label Name="lblTuesdayDate" / </Canvas <Canvas Grid.Column="4" Grid.Row="2" Margin="0" Style="{StaticResource DayField}" <Label Name="lblWednesdayDate" / </Canvas <Canvas Grid.Column="6" Grid.Row="2" Margin="0" Style="{StaticResource DayField}" <Label Name="lblThursdayDate" / </Canvas <Canvas Grid.Column="8" Grid.Row="2" Margin="0" Style="{StaticResource DayField}" <Label Name="lblFridayDate" / </Canvas <Canvas Grid.Column="10" Grid.Row="2" Margin="0" Style="{StaticResource DayField}" <Label Name="lblSaturdayDate" / </Canvas <Canvas Grid.Column="12" Grid.Row="2" Margin="0" Style="{StaticResource DayField}" <Label Name="lblSundayDate" / </Canvas </Grid </Canvas </Border <Canvas Height="86" HorizontalAlignment="Right" Margin="0,0,12,12" Name="canvas1" VerticalAlignment="Bottom" Width="198"</Canvas </Grid </Window CS: public partial class Window1 : Window { private DateTime today = new DateTime(); private Label[] Dates = new Label[7]; public Window1() { DateTime start = today = DateTime.Now; int day = (int)today.DayOfWeek; while (day != 1) { start = start.Subtract(new TimeSpan(1, 0, 0, 0)); day--; } InitializeComponent(); Dates[0] = lblMondayDate; Dates[1] = lblTuesdayDate; Dates[2] = lblWednesdayDate; Dates[3] = lblThursdayDate; Dates[4] = lblFridayDate; Dates[5] = lblSaturdayDate; Dates[6] = lblSundayDate; FillWeek(start); } private void FillWeek(DateTime start) { for (int d = 0; d < Dates.Length; d++) { TimeSpan td = new TimeSpan(d, 0, 0, 0); DateTime _day = start.Add(td); if (_day.Date == today.Date) { Canvas dayCanvas = (Canvas)Dates[d].Parent; dayCanvas.Style = (Style)this.Resources["Today"]; } Dates[d].Content = (int)start.Add(td).Day; } } } Thanks for any tips you guys can give Psytronic

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  • Synchronize Data between a Silverlight ListBox and a User Control

    - by psheriff
    One of the great things about XAML is the powerful data-binding capabilities. If you load up a list box with a collection of objects, you can display detail data about each object without writing any C# or VB.NET code. Take a look at Figure 1 that shows a collection of Product objects in a list box. When you click on a list box you bind the current Product object selected in the list box to a set of controls in a user control with just a very simple Binding statement in XAML.  Figure 1: Synchronizing a ListBox to a User Control is easy with Data Binding Product and Products Classes To illustrate this data binding feature I am going to just create some local data instead of using a WCF service. The code below shows a Product class that has three properties, namely, ProductId, ProductName and Price. This class also has a constructor that takes 3 parameters and allows us to set the 3 properties in an instance of our Product class. C#public class Product{  public Product(int productId, string productName, decimal price)  {    ProductId = productId;    ProductName = productName;    Price = price;  }   public int ProductId { get; set; }  public string ProductName { get; set; }  public decimal Price { get; set; }} VBPublic Class Product  Public Sub New(ByVal _productId As Integer, _                 ByVal _productName As String, _                 ByVal _price As Decimal)    ProductId = _productId    ProductName = _productName    Price = _price  End Sub   Private mProductId As Integer  Private mProductName As String  Private mPrice As Decimal   Public Property ProductId() As Integer    Get      Return mProductId    End Get    Set(ByVal value As Integer)      mProductId = value    End Set  End Property   Public Property ProductName() As String    Get      Return mProductName    End Get    Set(ByVal value As String)      mProductName = value    End Set  End Property   Public Property Price() As Decimal    Get      Return mPrice    End Get    Set(ByVal value As Decimal)      mPrice = value    End Set  End PropertyEnd Class To fill up a list box you need a collection class of Product objects. The code below creates a generic collection class of Product objects. In the constructor of the Products class I have hard-coded five product objects and added them to the collection. In a real-world application you would get your data through a call to service to fill the list box, but for simplicity and just to illustrate the data binding, I am going to just hard code the data. C#public class Products : List<Product>{  public Products()  {    this.Add(new Product(1, "Microsoft VS.NET 2008", 1000));    this.Add(new Product(2, "Microsoft VS.NET 2010", 1000));    this.Add(new Product(3, "Microsoft Silverlight 4", 1000));    this.Add(new Product(4, "Fundamentals of N-Tier eBook", 20));    this.Add(new Product(5, "ASP.NET Security eBook", 20));  }} VBPublic Class Products  Inherits List(Of Product)   Public Sub New()    Me.Add(New Product(1, "Microsoft VS.NET 2008", 1000))    Me.Add(New Product(2, "Microsoft VS.NET 2010", 1000))    Me.Add(New Product(3, "Microsoft Silverlight 4", 1000))    Me.Add(New Product(4, "Fundamentals of N-Tier eBook", 20))    Me.Add(New Product(5, "ASP.NET Security eBook", 20))  End SubEnd Class The Product Detail User Control Below is a user control (named ucProduct) that is used to display the product detail information seen in the bottom portion of Figure 1. This is very basic XAML that just creates a text block and a text box control for each of the three properties in the Product class. Notice the {Binding Path=[PropertyName]} on each of the text box controls. This means that if the DataContext property of this user control is set to an instance of a Product class, then the data in the properties of that Product object will be displayed in each of the text boxes. <UserControl x:Class="SL_SyncListBoxAndUserControl_CS.ucProduct"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  HorizontalAlignment="Left"  VerticalAlignment="Top">  <Grid Margin="4">    <Grid.RowDefinitions>      <RowDefinition Height="Auto" />      <RowDefinition Height="Auto" />      <RowDefinition Height="Auto" />    </Grid.RowDefinitions>    <Grid.ColumnDefinitions>      <ColumnDefinition MinWidth="120" />      <ColumnDefinition />    </Grid.ColumnDefinitions>    <TextBlock Grid.Row="0"               Grid.Column="0"               Text="Product Id" />    <TextBox Grid.Row="0"             Grid.Column="1"             Text="{Binding Path=ProductId}" />    <TextBlock Grid.Row="1"               Grid.Column="0"               Text="Product Name" />    <TextBox Grid.Row="1"             Grid.Column="1"             Text="{Binding Path=ProductName}" />    <TextBlock Grid.Row="2"               Grid.Column="0"               Text="Price" />    <TextBox Grid.Row="2"             Grid.Column="1"             Text="{Binding Path=Price}" />  </Grid></UserControl> Synchronize ListBox with User Control You are now ready to fill the list box with the collection class of Product objects and then bind the SelectedItem of the list box to the Product detail user control. The XAML below is the complete code for Figure 1. <UserControl x:Class="SL_SyncListBoxAndUserControl_CS.MainPage"  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  xmlns:src="clr-namespace:SL_SyncListBoxAndUserControl_CS"  VerticalAlignment="Top"  HorizontalAlignment="Left">  <UserControl.Resources>    <src:Products x:Key="productCollection" />  </UserControl.Resources>  <Grid x:Name="LayoutRoot"        Margin="4"        Background="White">    <Grid.RowDefinitions>      <RowDefinition Height="Auto" />      <RowDefinition Height="*" />    </Grid.RowDefinitions>    <ListBox x:Name="lstData"             Grid.Row="0"             BorderBrush="Black"             BorderThickness="1"             ItemsSource="{Binding                   Source={StaticResource productCollection}}"             DisplayMemberPath="ProductName" />    <src:ucProduct x:Name="prodDetail"                   Grid.Row="1"                   DataContext="{Binding ElementName=lstData,                                          Path=SelectedItem}" />  </Grid></UserControl> The first step to making this happen is to reference the Silverlight project (SL_SyncListBoxAndUserControl_CS) where the Product and Products classes are located. I added this namespace and assigned it a namespace prefix of “src” as shown in the line below: xmlns:src="clr-namespace:SL_SyncListBoxAndUserControl_CS" Next, to use the data from an instance of the Products collection, you create a UserControl.Resources section in the XAML and add a tag that creates an instance of the Products class and assigns it a key of “productCollection”.   <UserControl.Resources>    <src:Products x:Key="productCollection" />  </UserControl.Resources> Next, you bind the list box to this productCollection object using the ItemsSource property. You bind the ItemsSource of the list box to the static resource named productCollection. You can then set the DisplayMemberPath attribute of the list box to any property of the Product class that you want. In the XAML below I used the ProductName property. <ListBox x:Name="lstData"         ItemsSource="{Binding             Source={StaticResource productCollection}}"         DisplayMemberPath="ProductName" /> You now need to create an instance of the ucProduct user contol below the list box. You do this by once again referencing the “src” namespace and typing in the name of the user control. You then set the DataContext property on this user control to a binding. The binding uses the ElementName attribute to bind to the list box name, in this case “lstData”. The Path of the data is SelectedItem. These two attributes together tell Silverlight to bind the DataContext to the selected item of the list box. That selected item is a Product object. So, once this is bound, the bindings on each text box in the user control are updated and display the current product information. <src:ucProduct x:Name="prodDetail"               DataContext="{Binding ElementName=lstData,                                      Path=SelectedItem}" /> Summary Once you understand the basics of data binding in XAML, you eliminate a lot code that is otherwise needed to move data into controls and out of controls back into an object. Connecting two controls together is easy by just binding using the ElementName and Path properties of the Binding markup extension. Another good tip out of this blog is use user controls and set the DataContext of the user control to have all of the data on the user control update through the bindings. NOTE: You can download the complete sample code (in both VB and C#) at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "SL – Synchronize List Box Data with User Control" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".

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  • A Communication System for XAML Applications

    - by psheriff
    In any application, you want to keep the coupling between any two or more objects as loose as possible. Coupling happens when one class contains a property that is used in another class, or uses another class in one of its methods. If you have this situation, then this is called strong or tight coupling. One popular design pattern to help with keeping objects loosely coupled is called the Mediator design pattern. The basics of this pattern are very simple; avoid one object directly talking to another object, and instead use another class to mediate between the two. As with most of my blog posts, the purpose is to introduce you to a simple approach to using a message broker, not all of the fine details. IPDSAMessageBroker Interface As with most implementations of a design pattern, you typically start with an interface or an abstract base class. In this particular instance, an Interface will work just fine. The interface for our Message Broker class just contains a single method “SendMessage” and one event “MessageReceived”. public delegate void MessageReceivedEventHandler( object sender, PDSAMessageBrokerEventArgs e); public interface IPDSAMessageBroker{  void SendMessage(PDSAMessageBrokerMessage msg);   event MessageReceivedEventHandler MessageReceived;} PDSAMessageBrokerMessage Class As you can see in the interface, the SendMessage method requires a type of PDSAMessageBrokerMessage to be passed to it. This class simply has a MessageName which is a ‘string’ type and a MessageBody property which is of the type ‘object’ so you can pass whatever you want in the body. You might pass a string in the body, or a complete Customer object. The MessageName property will help the receiver of the message know what is in the MessageBody property. public class PDSAMessageBrokerMessage{  public PDSAMessageBrokerMessage()  {  }   public PDSAMessageBrokerMessage(string name, object body)  {    MessageName = name;    MessageBody = body;  }   public string MessageName { get; set; }   public object MessageBody { get; set; }} PDSAMessageBrokerEventArgs Class As our message broker class will be raising an event that others can respond to, it is a good idea to create your own event argument class. This class will inherit from the System.EventArgs class and add a couple of additional properties. The properties are the MessageName and Message. The MessageName property is simply a string value. The Message property is a type of a PDSAMessageBrokerMessage class. public class PDSAMessageBrokerEventArgs : EventArgs{  public PDSAMessageBrokerEventArgs()  {  }   public PDSAMessageBrokerEventArgs(string name,     PDSAMessageBrokerMessage msg)  {    MessageName = name;    Message = msg;  }   public string MessageName { get; set; }   public PDSAMessageBrokerMessage Message { get; set; }} PDSAMessageBroker Class Now that you have an interface class and a class to pass a message through an event, it is time to create your actual PDSAMessageBroker class. This class implements the SendMessage method and will also create the event handler for the delegate created in your Interface. public class PDSAMessageBroker : IPDSAMessageBroker{  public void SendMessage(PDSAMessageBrokerMessage msg)  {    PDSAMessageBrokerEventArgs args;     args = new PDSAMessageBrokerEventArgs(      msg.MessageName, msg);     RaiseMessageReceived(args);  }   public event MessageReceivedEventHandler MessageReceived;   protected void RaiseMessageReceived(    PDSAMessageBrokerEventArgs e)  {    if (null != MessageReceived)      MessageReceived(this, e);  }} The SendMessage method will take a PDSAMessageBrokerMessage object as an argument. It then creates an instance of a PDSAMessageBrokerEventArgs class, passing to the constructor two items: the MessageName from the PDSAMessageBrokerMessage object and also the object itself. It may seem a little redundant to pass in the message name when that same message name is part of the message, but it does make consuming the event and checking for the message name a little cleaner – as you will see in the next section. Create a Global Message Broker In your WPF application, create an instance of this message broker class in the App class located in the App.xaml file. Create a public property in the App class and create a new instance of that class in the OnStartUp event procedure as shown in the following code: public partial class App : Application{  public PDSAMessageBroker MessageBroker { get; set; }   protected override void OnStartup(StartupEventArgs e)  {    base.OnStartup(e);     MessageBroker = new PDSAMessageBroker();  }} Sending and Receiving Messages Let’s assume you have a user control that you load into a control on your main window and you want to send a message from that user control to the main window. You might have the main window display a message box, or put a string into a status bar as shown in Figure 1. Figure 1: The main window can receive and send messages The first thing you do in the main window is to hook up an event procedure to the MessageReceived event of the global message broker. This is done in the constructor of the main window: public MainWindow(){  InitializeComponent();   (Application.Current as App).MessageBroker.     MessageReceived += new MessageReceivedEventHandler(       MessageBroker_MessageReceived);} One piece of code you might not be familiar with is accessing a property defined in the App class of your XAML application. Within the App.Xaml file is a class named App that inherits from the Application object. You access the global instance of this App class by using Application.Current. You cast Application.Current to ‘App’ prior to accessing any of the public properties or methods you defined in the App class. Thus, the code (Application.Current as App).MessageBroker, allows you to get at the MessageBroker property defined in the App class. In the MessageReceived event procedure in the main window (shown below) you can now check to see if the MessageName property of the PDSAMessageBrokerEventArgs is equal to “StatusBar” and if it is, then display the message body into the status bar text block control. void MessageBroker_MessageReceived(object sender,   PDSAMessageBrokerEventArgs e){  switch (e.MessageName)  {    case "StatusBar":      tbStatus.Text = e.Message.MessageBody.ToString();      break;  }} In the Page 1 user control’s Loaded event procedure you will send the message “StatusBar” through the global message broker to any listener using the following code: private void UserControl_Loaded(object sender,  RoutedEventArgs e){  // Send Status Message  (Application.Current as App).MessageBroker.    SendMessage(new PDSAMessageBrokerMessage("StatusBar",      "This is Page 1"));} Since the main window is listening for the message ‘StatusBar’, it will display the value “This is Page 1” in the status bar at the bottom of the main window. Sending a Message to a User Control The previous example sent a message from the user control to the main window. You can also send messages from the main window to any listener as well. Remember that the global message broker is really just a broadcaster to anyone who has hooked into the MessageReceived event. In the constructor of the user control named ucPage1 you can hook into the global message broker’s MessageReceived event. You can then listen for any messages that are sent to this control by using a similar switch-case structure like that in the main window. public ucPage1(){  InitializeComponent();   // Hook to the Global Message Broker  (Application.Current as App).MessageBroker.    MessageReceived += new MessageReceivedEventHandler(      MessageBroker_MessageReceived);} void MessageBroker_MessageReceived(object sender,  PDSAMessageBrokerEventArgs e){  // Look for messages intended for Page 1  switch (e.MessageName)  {    case "ForPage1":      MessageBox.Show(e.Message.MessageBody.ToString());      break;  }} Once the ucPage1 user control has been loaded into the main window you can then send a message using the following code: private void btnSendToPage1_Click(object sender,  RoutedEventArgs e){  PDSAMessageBrokerMessage arg =     new PDSAMessageBrokerMessage();   arg.MessageName = "ForPage1";  arg.MessageBody = "Message For Page 1";   // Send a message to Page 1  (Application.Current as App).MessageBroker.SendMessage(arg);} Since the MessageName matches what is in the ucPage1 MessageReceived event procedure, ucPage1 can do anything in response to that event. It is important to note that when the message gets sent it is sent to all MessageReceived event procedures, not just the one that is looking for a message called “ForPage1”. If the user control ucPage1 is not loaded and this message is broadcast, but no other code is listening for it, then it is simply ignored. Remove Event Handler In each class where you add an event handler to the MessageReceived event you need to make sure to remove those event handlers when you are done. Failure to do so can cause a strong reference to the class and thus not allow that object to be garbage collected. In each of your user control’s make sure in the Unloaded event to remove the event handler. private void UserControl_Unloaded(object sender, RoutedEventArgs e){  if (_MessageBroker != null)    _MessageBroker.MessageReceived -=         _MessageBroker_MessageReceived;} Problems with Message Brokering As with most “global” classes or classes that hook up events to other classes, garbage collection is something you need to consider. Just the simple act of hooking up an event procedure to a global event handler creates a reference between your user control and the message broker in the App class. This means that even when your user control is removed from your UI, the class will still be in memory because of the reference to the message broker. This can cause messages to still being handled even though the UI is not being displayed. It is up to you to make sure you remove those event handlers as discussed in the previous section. If you don’t, then the garbage collector cannot release those objects. Instead of using events to send messages from one object to another you might consider registering your objects with a central message broker. This message broker now becomes a collection class into which you pass an object and what messages that object wishes to receive. You do end up with the same problem however. You have to un-register your objects; otherwise they still stay in memory. To alleviate this problem you can look into using the WeakReference class as a method to store your objects so they can be garbage collected if need be. Discussing Weak References is beyond the scope of this post, but you can look this up on the web. Summary In this blog post you learned how to create a simple message broker system that will allow you to send messages from one object to another without having to reference objects directly. This does reduce the coupling between objects in your application. You do need to remember to get rid of any event handlers prior to your objects going out of scope or you run the risk of having memory leaks and events being called even though you can no longer access the object that is responding to that event. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A Communication System for XAML Applications” from the drop down list.

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  • Is this fix to "PostSharp complains about CA1800:DoNotCastUnnecessarily" the best one?

    - by cad
    This question is about "is" and "as" in casting and about CA1800 PostSharp rule. I want to know if the solution I thought is the best one possible or if it have any problem that I can't see. I have this code (named OriginaL Code and reduced to the minimum relevant). The function ValidateSubscriptionLicenceProducts try to validate a SubscriptionLicence (that could be of 3 types: Standard,Credit and TimeLimited ) by casting it and checking later some stuff (in //Do Whatever). PostSharp complains about CA1800:DoNotCastUnnecessarily. The reason is that I am casting two times the same object to the same type. This code in best case will cast 2 times (if it is a StandardLicence) and in worst case 4 times (If it is a TimeLimited Licence). I know is possible to invalidate rule (it was my first approach), as there is no big impact in performance here, but I am trying a best approach. //Version Original Code //Min 2 casts, max 4 casts //PostSharp Complains about CA1800:DoNotCastUnnecessarily private void ValidateSubscriptionLicenceProducts(SubscriptionLicence licence) { if (licence is StandardSubscriptionLicence) { // All products must have the same products purchased List<StandardSubscriptionLicenceProduct> standardProducts = ((StandardSubscriptionLicence)licence).SubscribedProducts; //Do whatever } else if (licence is CreditSubscriptionLicence) { // All products must have a valid Credit entitlement & Credit interval List<CreditSubscriptionLicenceProduct> creditProducts = ((CreditSubscriptionLicence)licence).SubscribedProducts; //Do whatever } else if (licence is TimeLimitedSubscriptionLicence) { // All products must have a valid Time entitlement // All products must have a valid Credit entitlement & Credit interval List<TimeLimitedSubscriptionLicenceProduct> creditProducts = ((TimeLimitedSubscriptionLicence)licence).SubscribedProducts; //Do whatever } else throw new InvalidSubscriptionLicenceException("Invalid Licence type"); //More code... } This is Improved1 version using "as". Do not complain about CA1800 but the problem is that it will cast always 3 times (if in the future we have 30 or 40 types of licences it could perform bad) //Version Improve 1 //Minimum 3 casts, maximum 3 casts private void ValidateSubscriptionLicenceProducts(SubscriptionLicence licence) { StandardSubscriptionLicence standardLicence = Slicence as StandardSubscriptionLicence; CreditSubscriptionLicence creditLicence = Clicence as CreditSubscriptionLicence; TimeLimitedSubscriptionLicence timeLicence = Tlicence as TimeLimitedSubscriptionLicence; if (Slicence == null) { // All products must have the same products purchased List<StandardSubscriptionLicenceProduct> standardProducts = Slicence.SubscribedProducts; //Do whatever } else if (Clicence == null) { // All products must have a valid Credit entitlement & Credit interval List<CreditSubscriptionLicenceProduct> creditProducts = Clicence.SubscribedProducts; //Do whatever } else if (Tlicence == null) { // All products must have a valid Time entitlement // All products must have a valid Credit entitlement & Credit interval List<TimeLimitedSubscriptionLicenceProduct> creditProducts = Tlicence.SubscribedProducts; //Do whatever } else throw new InvalidSubscriptionLicenceException("Invalid Licence type"); //More code... } But later I thought in a best one. This is the final version I am using. //Version Improve 2 // Min 1 cast, Max 3 Casts // Do not complain about CA1800:DoNotCastUnnecessarily private void ValidateSubscriptionLicenceProducts(SubscriptionLicence licence) { StandardSubscriptionLicence standardLicence = null; CreditSubscriptionLicence creditLicence = null; TimeLimitedSubscriptionLicence timeLicence = null; if (StandardSubscriptionLicence.TryParse(licence, out standardLicence)) { // All products must have the same products purchased List<StandardSubscriptionLicenceProduct> standardProducts = standardLicence.SubscribedProducts; //Do whatever } else if (CreditSubscriptionLicence.TryParse(licence, out creditLicence)) { // All products must have a valid Credit entitlement & Credit interval List<CreditSubscriptionLicenceProduct> creditProducts = creditLicence.SubscribedProducts; //Do whatever } else if (TimeLimitedSubscriptionLicence.TryParse(licence, out timeLicence)) { // All products must have a valid Time entitlement List<TimeLimitedSubscriptionLicenceProduct> timeProducts = timeLicence.SubscribedProducts; //Do whatever } else throw new InvalidSubscriptionLicenceException("Invalid Licence type"); //More code... } //Example of TryParse in CreditSubscriptionLicence public static bool TryParse(SubscriptionLicence baseLicence, out CreditSubscriptionLicence creditLicence) { creditLicence = baseLicence as CreditSubscriptionLicence; if (creditLicence != null) return true; else return false; } It requires a change in the classes StandardSubscriptionLicence, CreditSubscriptionLicence and TimeLimitedSubscriptionLicence to have a "tryparse" method (copied below in the code). This version I think it will cast as minimum only once and as maximum three. What do you think about improve 2? Is there a best way of doing it?

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  • Wicket testing - AnnotApplicationContextMock - There is no application attached to current thread ma

    - by John
    I've written a couple of tests for a small web app, but I get an error when I try to run the page specific tests that makes use of WicketTester. Google sends me to a mailing list for Apache Wicket, where a user experienced the same exception. He/she said the problem was that AnnotApplicationContextMock was initialized before the Wicket Application. I've pasted my WicketApplication class as well. Has any of you dealt with this error before? I've pasted the exception and the class below. Exception: ------------------------------------------------------------------------------- Test set: com.upbeat.shoutbox.web.TestViewShoutsPage ------------------------------------------------------------------------------- Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 1.545 sec (AnnotApplicationContextMock.java:61) at com.upbeat.shoutbox.web.TestViewShoutsPage.setUp(TestViewShoutsPage.java:30) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.internal.runners.MethodRoadie.runBefores(MethodRoadie.java:129) at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:93) at org.unitils.UnitilsJUnit4TestClassRunner$CustomMethodRoadie.runBeforesThenTestThenAfters(UnitilsJUnit4TestClassRunner.java:168) at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:84) at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:49) at org.unitils.UnitilsJUnit4TestClassRunner.invokeTestMethod(UnitilsJUnit4TestClassRunner.java:127) at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:59) at org.unitils.UnitilsJUnit4TestClassRunner.access$000(UnitilsJUnit4TestClassRunner.java:42) at org.unitils.UnitilsJUnit4TestClassRunner$1.run(UnitilsJUnit4TestClassRunner.java:87) at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34) at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44) at org.unitils.UnitilsJUnit4TestClassRunner.run(UnitilsJUnit4TestClassRunner.java:94) at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:62) at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.executeTestSet(AbstractDirectoryTestSuite.java:140) at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.execute(AbstractDirectoryTestSuite.java:127) at org.apache.maven.surefire.Surefire.run(Surefire.java:177) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.maven.surefire.booter.SurefireBooter.runSuitesInProcess(SurefireBooter.java:345) at org.apache.maven.surefire.booter.SurefireBooter.main(SurefireBooter.java:1009) My page specific test class: package com.upbeat.shoutbox.web; import org.apache.wicket.application.IComponentInstantiationListener; import org.apache.wicket.protocol.http.WebApplication; import org.apache.wicket.spring.injection.annot.SpringComponentInjector; import org.apache.wicket.spring.injection.annot.test.AnnotApplicationContextMock; import org.apache.wicket.util.tester.FormTester; import org.apache.wicket.util.tester.WicketTester; import org.junit.Before; import org.junit.Test; import org.unitils.spring.annotation.SpringBeanByType; import com.upbeat.shoutbox.WicketApplication; import com.upbeat.shoutbox.integrations.AbstractIntegrationTest; import com.upbeat.shoutbox.persistence.ShoutItemDao; import com.upbeat.shoutbox.services.ShoutService; import com.upbeat.shoutbox.web.pages.ViewShoutsPage; public class TestViewShoutsPage extends AbstractIntegrationTest { @SpringBeanByType private ShoutService svc; @SpringBeanByType private ShoutItemDao dao; protected WicketTester tester; @Before public void setUp() { final AnnotApplicationContextMock appctx = new AnnotApplicationContextMock(); appctx.putBean("ShoutItemDao", dao); appctx.putBean("ShoutService", svc); tester = new WicketTester(new WicketApplication() { @Override protected IComponentInstantiationListener getSpringComponentInjector(WebApplication app) { return new SpringComponentInjector(app, appctx, false); } }); } @Test public void testRenderPage() { tester.startPage(ViewShoutsPage.class); tester.assertRenderedPage(ViewShoutsPage.class); FormTester ft = tester.newFormTester("addShoutForm"); ft.setValue("nickname", "test-nickname"); ft.setValue("content", "a whole lot of content"); ft.submit(); tester.assertRenderedPage(ViewShoutsPage.class); tester.assertContains("test-nickname"); tester.assertContains("a whole lot of content"); } } AbstractIntegrationTest: package com.upbeat.shoutbox.integrations; import org.springframework.context.ApplicationContext; import org.unitils.UnitilsJUnit4; import org.unitils.spring.annotation.SpringApplicationContext; @SpringApplicationContext({"/com/upbeat/shoutbox/spring/applicationContext.xml", "applicationContext-test.xml"}) public abstract class AbstractIntegrationTest extends UnitilsJUnit4 { private ApplicationContext applicationContext; } WicketApplication: package com.upbeat.shoutbox; import org.apache.wicket.application.IComponentInstantiationListener; import org.apache.wicket.protocol.http.WebApplication; import org.apache.wicket.request.target.coding.IndexedParamUrlCodingStrategy; import org.apache.wicket.spring.injection.annot.SpringComponentInjector; import com.upbeat.shoutbox.web.pages.ParamPage; import com.upbeat.shoutbox.web.pages.VeryNiceExceptionPage; /** * Application object for your web application. If you want to run this application without deploying, run the Start class. * * @see com.upbeat.shoutbox.Start#main(String[]) */ public class WicketApplication extends WebApplication { /** * Constructor */ public WicketApplication() { } /** * @see org.apache.wicket.Application#getHomePage() */ public Class getHomePage() { return HomePage.class; } @Override protected void init() { super.init(); // Enable wicket ajax debug getDebugSettings().setAjaxDebugModeEnabled(true); addComponentInstantiationListener(getSpringComponentInjector(this)); // Mount pages mountBookmarkablePage("/home", HomePage.class); mountBookmarkablePage("/exceptionPage", VeryNiceExceptionPage.class); mount(new IndexedParamUrlCodingStrategy("/view_params", ParamPage.class)); } protected IComponentInstantiationListener getSpringComponentInjector(WebApplication app) { return new SpringComponentInjector(app); } }

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  • Windows Azure Service Bus Splitter and Aggregator

    - by Alan Smith
    This article will cover basic implementations of the Splitter and Aggregator patterns using the Windows Azure Service Bus. The content will be included in the next release of the “Windows Azure Service Bus Developer Guide”, along with some other patterns I am working on. I’ve taken the pattern descriptions from the book “Enterprise Integration Patterns” by Gregor Hohpe. I bought a copy of the book in 2004, and recently dusted it off when I started to look at implementing the patterns on the Windows Azure Service Bus. Gregor has also presented an session in 2011 “Enterprise Integration Patterns: Past, Present and Future” which is well worth a look. I’ll be covering more patterns in the coming weeks, I’m currently working on Wire-Tap and Scatter-Gather. There will no doubt be a section on implementing these patterns in my “SOA, Connectivity and Integration using the Windows Azure Service Bus” course. There are a number of scenarios where a message needs to be divided into a number of sub messages, and also where a number of sub messages need to be combined to form one message. The splitter and aggregator patterns provide a definition of how this can be achieved. This section will focus on the implementation of basic splitter and aggregator patens using the Windows Azure Service Bus direct programming model. In BizTalk Server receive pipelines are typically used to implement the splitter patterns, with sequential convoy orchestrations often used to aggregate messages. In the current release of the Service Bus, there is no functionality in the direct programming model that implements these patterns, so it is up to the developer to implement them in the applications that send and receive messages. Splitter A message splitter takes a message and spits the message into a number of sub messages. As there are different scenarios for how a message can be split into sub messages, message splitters are implemented using different algorithms. The Enterprise Integration Patterns book describes the splatter pattern as follows: How can we process a message if it contains multiple elements, each of which may have to be processed in a different way? Use a Splitter to break out the composite message into a series of individual messages, each containing data related to one item. The Enterprise Integration Patterns website provides a description of the Splitter pattern here. In some scenarios a batch message could be split into the sub messages that are contained in the batch. The splitting of a message could be based on the message type of sub-message, or the trading partner that the sub message is to be sent to. Aggregator An aggregator takes a stream or related messages and combines them together to form one message. The Enterprise Integration Patterns book describes the aggregator pattern as follows: How do we combine the results of individual, but related messages so that they can be processed as a whole? Use a stateful filter, an Aggregator, to collect and store individual messages until a complete set of related messages has been received. Then, the Aggregator publishes a single message distilled from the individual messages. The Enterprise Integration Patterns website provides a description of the Aggregator pattern here. A common example of the need for an aggregator is in scenarios where a stream of messages needs to be combined into a daily batch to be sent to a legacy line-of-business application. The BizTalk Server EDI functionality provides support for batching messages in this way using a sequential convoy orchestration. Scenario The scenario for this implementation of the splitter and aggregator patterns is the sending and receiving of large messages using a Service Bus queue. In the current release, the Windows Azure Service Bus currently supports a maximum message size of 256 KB, with a maximum header size of 64 KB. This leaves a safe maximum body size of 192 KB. The BrokeredMessage class will support messages larger than 256 KB; in fact the Size property is of type long, implying that very large messages may be supported at some point in the future. The 256 KB size restriction is set in the service bus components that are deployed in the Windows Azure data centers. One of the ways of working around this size restriction is to split large messages into a sequence of smaller sub messages in the sending application, send them via a queue, and then reassemble them in the receiving application. This scenario will be used to demonstrate the pattern implementations. Implementation The splitter and aggregator will be used to provide functionality to send and receive large messages over the Windows Azure Service Bus. In order to make the implementations generic and reusable they will be implemented as a class library. The splitter will be implemented in the LargeMessageSender class and the aggregator in the LargeMessageReceiver class. A class diagram showing the two classes is shown below. Implementing the Splitter The splitter will take a large brokered message, and split the messages into a sequence of smaller sub-messages that can be transmitted over the service bus messaging entities. The LargeMessageSender class provides a Send method that takes a large brokered message as a parameter. The implementation of the class is shown below; console output has been added to provide details of the splitting operation. public class LargeMessageSender {     private static int SubMessageBodySize = 192 * 1024;     private QueueClient m_QueueClient;       public LargeMessageSender(QueueClient queueClient)     {         m_QueueClient = queueClient;     }       public void Send(BrokeredMessage message)     {         // Calculate the number of sub messages required.         long messageBodySize = message.Size;         int nrSubMessages = (int)(messageBodySize / SubMessageBodySize);         if (messageBodySize % SubMessageBodySize != 0)         {             nrSubMessages++;         }           // Create a unique session Id.         string sessionId = Guid.NewGuid().ToString();         Console.WriteLine("Message session Id: " + sessionId);         Console.Write("Sending {0} sub-messages", nrSubMessages);           Stream bodyStream = message.GetBody<Stream>();         for (int streamOffest = 0; streamOffest < messageBodySize;             streamOffest += SubMessageBodySize)         {                                     // Get the stream chunk from the large message             long arraySize = (messageBodySize - streamOffest) > SubMessageBodySize                 ? SubMessageBodySize : messageBodySize - streamOffest;             byte[] subMessageBytes = new byte[arraySize];             int result = bodyStream.Read(subMessageBytes, 0, (int)arraySize);             MemoryStream subMessageStream = new MemoryStream(subMessageBytes);               // Create a new message             BrokeredMessage subMessage = new BrokeredMessage(subMessageStream, true);             subMessage.SessionId = sessionId;               // Send the message             m_QueueClient.Send(subMessage);             Console.Write(".");         }         Console.WriteLine("Done!");     }} The LargeMessageSender class is initialized with a QueueClient that is created by the sending application. When the large message is sent, the number of sub messages is calculated based on the size of the body of the large message. A unique session Id is created to allow the sub messages to be sent as a message session, this session Id will be used for correlation in the aggregator. A for loop in then used to create the sequence of sub messages by creating chunks of data from the stream of the large message. The sub messages are then sent to the queue using the QueueClient. As sessions are used to correlate the messages, the queue used for message exchange must be created with the RequiresSession property set to true. Implementing the Aggregator The aggregator will receive the sub messages in the message session that was created by the splitter, and combine them to form a single, large message. The aggregator is implemented in the LargeMessageReceiver class, with a Receive method that returns a BrokeredMessage. The implementation of the class is shown below; console output has been added to provide details of the splitting operation.   public class LargeMessageReceiver {     private QueueClient m_QueueClient;       public LargeMessageReceiver(QueueClient queueClient)     {         m_QueueClient = queueClient;     }       public BrokeredMessage Receive()     {         // Create a memory stream to store the large message body.         MemoryStream largeMessageStream = new MemoryStream();           // Accept a message session from the queue.         MessageSession session = m_QueueClient.AcceptMessageSession();         Console.WriteLine("Message session Id: " + session.SessionId);         Console.Write("Receiving sub messages");           while (true)         {             // Receive a sub message             BrokeredMessage subMessage = session.Receive(TimeSpan.FromSeconds(5));               if (subMessage != null)             {                 // Copy the sub message body to the large message stream.                 Stream subMessageStream = subMessage.GetBody<Stream>();                 subMessageStream.CopyTo(largeMessageStream);                   // Mark the message as complete.                 subMessage.Complete();                 Console.Write(".");             }             else             {                 // The last message in the sequence is our completeness criteria.                 Console.WriteLine("Done!");                 break;             }         }                     // Create an aggregated message from the large message stream.         BrokeredMessage largeMessage = new BrokeredMessage(largeMessageStream, true);         return largeMessage;     } }   The LargeMessageReceiver initialized using a QueueClient that is created by the receiving application. The receive method creates a memory stream that will be used to aggregate the large message body. The AcceptMessageSession method on the QueueClient is then called, which will wait for the first message in a message session to become available on the queue. As the AcceptMessageSession can throw a timeout exception if no message is available on the queue after 60 seconds, a real-world implementation should handle this accordingly. Once the message session as accepted, the sub messages in the session are received, and their message body streams copied to the memory stream. Once all the messages have been received, the memory stream is used to create a large message, that is then returned to the receiving application. Testing the Implementation The splitter and aggregator are tested by creating a message sender and message receiver application. The payload for the large message will be one of the webcast video files from http://www.cloudcasts.net/, the file size is 9,697 KB, well over the 256 KB threshold imposed by the Service Bus. As the splitter and aggregator are implemented in a separate class library, the code used in the sender and receiver console is fairly basic. The implementation of the main method of the sending application is shown below.   static void Main(string[] args) {     // Create a token provider with the relevant credentials.     TokenProvider credentials =         TokenProvider.CreateSharedSecretTokenProvider         (AccountDetails.Name, AccountDetails.Key);       // Create a URI for the serivce bus.     Uri serviceBusUri = ServiceBusEnvironment.CreateServiceUri         ("sb", AccountDetails.Namespace, string.Empty);       // Create the MessagingFactory     MessagingFactory factory = MessagingFactory.Create(serviceBusUri, credentials);       // Use the MessagingFactory to create a queue client     QueueClient queueClient = factory.CreateQueueClient(AccountDetails.QueueName);       // Open the input file.     FileStream fileStream = new FileStream(AccountDetails.TestFile, FileMode.Open);       // Create a BrokeredMessage for the file.     BrokeredMessage largeMessage = new BrokeredMessage(fileStream, true);       Console.WriteLine("Sending: " + AccountDetails.TestFile);     Console.WriteLine("Message body size: " + largeMessage.Size);     Console.WriteLine();         // Send the message with a LargeMessageSender     LargeMessageSender sender = new LargeMessageSender(queueClient);     sender.Send(largeMessage);       // Close the messaging facory.     factory.Close();  } The implementation of the main method of the receiving application is shown below. static void Main(string[] args) {       // Create a token provider with the relevant credentials.     TokenProvider credentials =         TokenProvider.CreateSharedSecretTokenProvider         (AccountDetails.Name, AccountDetails.Key);       // Create a URI for the serivce bus.     Uri serviceBusUri = ServiceBusEnvironment.CreateServiceUri         ("sb", AccountDetails.Namespace, string.Empty);       // Create the MessagingFactory     MessagingFactory factory = MessagingFactory.Create(serviceBusUri, credentials);       // Use the MessagingFactory to create a queue client     QueueClient queueClient = factory.CreateQueueClient(AccountDetails.QueueName);       // Create a LargeMessageReceiver and receive the message.     LargeMessageReceiver receiver = new LargeMessageReceiver(queueClient);     BrokeredMessage largeMessage = receiver.Receive();       Console.WriteLine("Received message");     Console.WriteLine("Message body size: " + largeMessage.Size);       string testFile = AccountDetails.TestFile.Replace(@"\In\", @"\Out\");     Console.WriteLine("Saving file: " + testFile);       // Save the message body as a file.     Stream largeMessageStream = largeMessage.GetBody<Stream>();     largeMessageStream.Seek(0, SeekOrigin.Begin);     FileStream fileOut = new FileStream(testFile, FileMode.Create);     largeMessageStream.CopyTo(fileOut);     fileOut.Close();       Console.WriteLine("Done!"); } In order to test the application, the sending application is executed, which will use the LargeMessageSender class to split the message and place it on the queue. The output of the sender console is shown below. The console shows that the body size of the large message was 9,929,365 bytes, and the message was sent as a sequence of 51 sub messages. When the receiving application is executed the results are shown below. The console application shows that the aggregator has received the 51 messages from the message sequence that was creating in the sending application. The messages have been aggregated to form a massage with a body of 9,929,365 bytes, which is the same as the original large message. The message body is then saved as a file. Improvements to the Implementation The splitter and aggregator patterns in this implementation were created in order to show the usage of the patterns in a demo, which they do quite well. When implementing these patterns in a real-world scenario there are a number of improvements that could be made to the design. Copying Message Header Properties When sending a large message using these classes, it would be great if the message header properties in the message that was received were copied from the message that was sent. The sending application may well add information to the message context that will be required in the receiving application. When the sub messages are created in the splitter, the header properties in the first message could be set to the values in the original large message. The aggregator could then used the values from this first sub message to set the properties in the message header of the large message during the aggregation process. Using Asynchronous Methods The current implementation uses the synchronous send and receive methods of the QueueClient class. It would be much more performant to use the asynchronous methods, however doing so may well affect the sequence in which the sub messages are enqueued, which would require the implementation of a resequencer in the aggregator to restore the correct message sequence. Handling Exceptions In order to keep the code readable no exception handling was added to the implementations. In a real-world scenario exceptions should be handled accordingly.

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  • Hibernate exception

    - by Mark
    Hi all, im new to hibernate! i have followed the netbeans tutorial on creating a hibernate enabled application. after sucessfully creating a database in mysql workbench i reversed engineered the pojos etc and then tried to run a simple query(from Course) and got the following org.hibernate.MappingException: An association from the table coursemodule refers to an unmapped class: DAL.Module at org.hibernate.cfg.Configuration.secondPassCompileForeignKeys(Configuration.java:1252) at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1170) at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:324) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1286) at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:859) heres the generated class for Course package DAL; // Generated 02-May-2010 16:41:16 by Hibernate Tools 3.2.1.GA import java.util.HashSet; import java.util.Set; /** * Course generated by hbm2java */ public class Course implements java.io.Serializable { private int id; private String name; private Set<Module> modules = new HashSet<Module>(0); public Course() { } public Course(int id, String name) { this.id = id; this.name = name; } public Course(int id, String name, Set<Module> modules) { this.id = id; this.name = name; this.modules = modules; } public int getId() { return this.id; } public void setId(int id) { this.id = id; } public String getName() { return this.name; } public void setName(String name) { this.name = name; } public Set<Module> getModules() { return this.modules; } public void setModules(Set<Module> modules) { this.modules = modules; } } and its config file course.hbm.xml <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <!-- Generated 02-May-2010 16:41:16 by Hibernate Tools 3.2.1.GA --> <hibernate-mapping> <class name="DAL.Course" table="course" catalog="walkthrough"> <id name="id" type="int"> <column name="id" /> <generator class="assigned" /> </id> <property name="name" type="string"> <column name="name" not-null="true" /> </property> <set name="modules" inverse="false" table="coursemodule"> <key> <column name="courseId" not-null="true" unique="true" /> </key> <many-to-many entity-name="DAL.Module"> <column name="moduleId" not-null="true" unique="true" /> </many-to-many> </set> </class> </hibernate-mapping> hibernate.reveng.xml <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-reverse-engineering PUBLIC "-//Hibernate/Hibernate Reverse Engineering DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-reverse-engineering-3.0.dtd"> <hibernate-reverse-engineering> <schema-selection match-catalog="Walkthrough"/> <table-filter match-name="walkthrough"/> <table-filter match-name="course"/> <table-filter match-name="module"/> <table-filter match-name="studentmodule"/> <table-filter match-name="attendee"/> <table-filter match-name="student"/> <table-filter match-name="coursemodule"/> <table-filter match-name="session"/> <table-filter match-name="test"/> </hibernate-reverse-engineering> hibernate.cfg.xml <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/Walkthrough</property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">password</property> <property name="hibernate.show_sql">true</property> <property name="hibernate.current_session_context_class">thread</property> <mapping resource="DAL/Student.hbm.xml"/> <mapping resource="DAL/Walkthrough.hbm.xml"/> <mapping resource="DAL/Test.hbm.xml"/> <mapping resource="DAL/Module.hbm.xml"/> <mapping resource="DAL/Session.hbm.xml"/> <mapping resource="DAL/Course.hbm.xml"/> </session-factory> </hibernate-configuration> any ideas on why im getting this exception? ps. test is just a table with an id in it and is not related to anything. running "from Test" works

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  • C# XNA Handle mouse events?

    - by user406470
    I'm making a 2D game engine called Clixel over on GitHub. The problem I have relates to two classes, ClxMouse and ClxButton. In it I have a mouse class - the code for that can be viewed here. ClxMouse using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; namespace org.clixel { public class ClxMouse : ClxSprite { private MouseState _curmouse, _lastmouse; public int Sensitivity = 3; public bool Lock = true; public Vector2 Change { get { return new Vector2(_curmouse.X - _lastmouse.X, _curmouse.Y - _lastmouse.Y); } } private int _scrollwheel; public int ScrollWheel { get { return _scrollwheel; } } public bool LeftDown { get { if (_curmouse.LeftButton == ButtonState.Pressed) return true; else return false; } } public bool RightDown { get { if (_curmouse.RightButton == ButtonState.Pressed) return true; else return false; } } public bool MiddleDown { get { if (_curmouse.MiddleButton == ButtonState.Pressed) return true; else return false; } } public bool LeftPressed { get { if (_curmouse.LeftButton == ButtonState.Pressed && _lastmouse.LeftButton == ButtonState.Released) return true; else return false; } } public bool RightPressed { get { if (_curmouse.RightButton == ButtonState.Pressed && _lastmouse.RightButton == ButtonState.Released) return true; else return false; } } public bool MiddlePressed { get { if (_curmouse.MiddleButton == ButtonState.Pressed && _lastmouse.MiddleButton == ButtonState.Released) return true; else return false; } } public bool LeftReleased { get { if (_curmouse.LeftButton == ButtonState.Released && _lastmouse.LeftButton == ButtonState.Pressed) return true; else return false; } } public bool RightReleased { get { if (_curmouse.RightButton == ButtonState.Released && _lastmouse.RightButton == ButtonState.Pressed) return true; else return false; } } public bool MiddleReleased { get { if (_curmouse.MiddleButton == ButtonState.Released && _lastmouse.MiddleButton == ButtonState.Pressed) return true; else return false; } } public MouseState CurMouse { get { return _curmouse; } } public MouseState LastMouse { get { return _lastmouse; } } public ClxMouse() : base(ClxG.Textures.Default.Cursor) { _curmouse = Mouse.GetState(); _lastmouse = _curmouse; CollisionBox = new Rectangle(ClxG.Screen.Center.X, ClxG.Screen.Center.Y, Texture.Width, Texture.Height); this.Solid = false; DefaultPosition = new Vector2(CollisionBox.X, CollisionBox.Y); Mouse.SetPosition(CollisionBox.X, CollisionBox.Y); } public ClxMouse(Texture2D _texture) : base(_texture) { _curmouse = Mouse.GetState(); _lastmouse = _curmouse; CollisionBox = new Rectangle(ClxG.Screen.Center.X, ClxG.Screen.Center.Y, Texture.Width, Texture.Height); DefaultPosition = new Vector2(CollisionBox.X, CollisionBox.Y); } public override void Update() { _lastmouse = _curmouse; _curmouse = Mouse.GetState(); if (_curmouse != _lastmouse) { if (ClxG.Game.IsActive) { _scrollwheel = _curmouse.ScrollWheelValue; Velocity = new Vector2(Change.X / Sensitivity, Change.Y / Sensitivity); if (Lock) Mouse.SetPosition(ClxG.Screen.Center.X, ClxG.Screen.Center.Y); _curmouse = Mouse.GetState(); } base.Update(); } } public override void Draw(SpriteBatch _sb) { base.Draw(_sb); } } } ClxButton using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Graphics; namespace org.clixel { public class ClxButton : ClxSprite { /// <summary> /// The color when the mouse is over the button /// </summary> public Color HoverColor; /// <summary> /// The color when the color is being clicked /// </summary> public Color ClickColor; /// <summary> /// The color when the button is inactive /// </summary> public Color InactiveColor; /// <summary> /// The color when the button is active /// </summary> public Color ActiveColor; /// <summary> /// The color after the button has been clicked. /// </summary> public Color ClickedColor; /// <summary> /// The text to be displayed on the button, set to "" if no text is needed. /// </summary> public string Text; /// <summary> /// The ClxText object to be displayed. /// </summary> public ClxText TextRender; /// <summary> /// The ClxState that should be ResetAndShow() when the button is clicked. /// </summary> public ClxState ClickState; /// <summary> /// Collision check to make sure onCollide() only runs once per frame, /// since only the mouse needs to be collision checked. /// </summary> private bool _runonce = false; /// <summary> /// Gets a value indicating whether this instance is colliding. /// </summary> /// <value> /// <c>true</c> if this instance is colliding; otherwise, <c>false</c>. /// </value> public bool IsColliding { get { return _runonce; } } /// <summary> /// Initializes a new instance of the <see cref="ClxButton"/> class. /// </summary> public ClxButton() : base(ClxG.Textures.Default.Button) { HoverColor = Color.Red; ClickColor = Color.Blue; InactiveColor = Color.Gray; ActiveColor = Color.White; ClickedColor = Color.Yellow; Text = Name + ID + " Unset!"; TextRender = new ClxText(); TextRender.Text = Text; TextRender.TextPadding = new Vector2(5, 5); ClickState = null; CollideObjects(ClxG.Mouse); } /// <summary> /// Initializes a new instance of the <see cref="ClxButton"/> class. /// </summary> /// <param name="_texture">The button texture.</param> public ClxButton(Texture2D _texture) : base(_texture) { HoverColor = Color.Red; ClickColor = Color.Blue; InactiveColor = Color.Gray; ActiveColor = Color.White; ClickedColor = Color.Yellow; Texture = _texture; Text = Name + ID; TextRender = new ClxText(); TextRender.Name = this.Name + ".TextRender"; TextRender.Text = Text; TextRender.TextPadding = new Vector2(5, 5); TextRender.Reset(); ClickState = null; CollideObjects(ClxG.Mouse); } /// <summary> /// Draws the debug information, run from ClxG.DrawDebug unless manual control is assumed. /// </summary> /// <param name="_sb">SpriteBatch used for drawing.</param> public override void DrawDebug(SpriteBatch _sb) { _runonce = false; TextRender.DrawDebug(_sb); _sb.Draw(Texture, ActualRectangle, new Rectangle(0, 0, Texture.Width, Texture.Height), DebugColor, Rotation, Origin, Flip, Layer); _sb.Draw(ClxG.Textures.Default.DebugBG, new Rectangle(ActualRectangle.X - DebugLineWidth, ActualRectangle.Y - DebugLineWidth, ActualRectangle.Width + DebugLineWidth * 2, ActualRectangle.Height + DebugLineWidth * 2), new Rectangle(0, 0, ClxG.Textures.Default.DebugBG.Width, ClxG.Textures.Default.DebugBG.Height), DebugOutline, Rotation, Origin, Flip, Layer - 0.1f); _sb.Draw(ClxG.Textures.Default.DebugBG, ActualRectangle, new Rectangle(0, 0, ClxG.Textures.Default.DebugBG.Width, ClxG.Textures.Default.DebugBG.Height), DebugBGColor, Rotation, Origin, Flip, Layer - 0.01f); } /// <summary> /// Draws using the SpriteBatch, run from ClxG.Draw unless manual control is assumed. /// </summary> /// <param name="_sb">SpriteBatch used for drawing.</param> public override void Draw(SpriteBatch _sb) { _runonce = false; TextRender.Draw(_sb); if (Visible) if (Debug) { DrawDebug(_sb); } else _sb.Draw(Texture, ActualRectangle, new Rectangle(0, 0, Texture.Width, Texture.Height), Color, Rotation, Origin, Flip, Layer); } /// <summary> /// Updates this instance. /// </summary> public override void Update() { if (this.Color != ActiveColor) this.Color = ActiveColor; TextRender.Layer = this.Layer + 0.03f; TextRender.Text = Text; TextRender.Scale = .5f; TextRender.Name = this.Name + ".TextRender"; TextRender.Origin = new Vector2(TextRender.CollisionBox.Center.X, TextRender.CollisionBox.Center.Y); TextRender.Center(this); TextRender.Update(); this.CollisionBox.Width = (int)(TextRender.CollisionBox.Width * TextRender.Scale) + (int)(TextRender.TextPadding.X * 2); this.CollisionBox.Height = (int)(TextRender.CollisionBox.Height * TextRender.Scale) + (int)(TextRender.TextPadding.Y * 2); base.Update(); } /// <summary> /// Collide event, takes the colliding object to call it's proper collision code. /// You'd want to use something like if(typeof(collider) == typeof(ClxObject) /// </summary> /// <param name="collider">The colliding object.</param> public override void onCollide(ClxObject collider) { if (!_runonce) { _runonce = true; UpdateEvents(); base.onCollide(collider); } } /// <summary> /// Updates the mouse based events. /// </summary> public void UpdateEvents() { onHover(); if (ClxG.Mouse.LeftReleased) { onLeftReleased(); return; } if (ClxG.Mouse.RightReleased) { onRightReleased(); return; } if (ClxG.Mouse.MiddleReleased) { onMiddleReleased(); return; } if (ClxG.Mouse.LeftPressed) { onLeftClicked(); return; } if (ClxG.Mouse.RightPressed) { onRightClicked(); return; } if (ClxG.Mouse.MiddlePressed) { onMiddleClicked(); return; } if (ClxG.Mouse.LeftDown) { onLeftClick(); return; } if (ClxG.Mouse.RightDown) { onRightClick(); return; } if (ClxG.Mouse.MiddleDown) { onMiddleClick(); return; } } /// <summary> /// Shows the state of the click. /// </summary> public void ShowClickState() { if (ClickState != null) { ClickState.ResetAndShow(); } } /// <summary> /// Hover event /// </summary> virtual public void onHover() { this.Color = HoverColor; } /// <summary> /// Left click event /// </summary> virtual public void onLeftClick() { this.Color = ClickColor; } /// <summary> /// Right click event /// </summary> virtual public void onRightClick() { } /// <summary> /// Middle click event /// </summary> virtual public void onMiddleClick() { } /// <summary> /// Left click event, called once per click /// </summary> virtual public void onLeftClicked() { ShowClickState(); } /// <summary> /// Right click event, called once per click /// </summary> virtual public void onRightClicked() { this.Reset(); } /// <summary> /// Middle click event, called once per click /// </summary> virtual public void onMiddleClicked() { } /// <summary> /// Ons the left released. /// </summary> virtual public void onLeftReleased() { this.Color = ClickedColor; } virtual public void onRightReleased() { } virtual public void onMiddleReleased() { } } } The issue I have is that I have all these have event styled methods, especially in ClxButton with all the onLeftClick, onRightClick, etc, etc. Is there a better way for me to handle these events to be a lot more easier for a programmer to use? I was looking at normal events on some other sites, (I'd post them but I need more rep.) and didn't really see a good way to implement delegate events into my framework. I'm not really sure how these events work, could someone possibly lay out how these events are processed for me? TL:DR * Is there a better way to handle events like this? * Are events a viable solution to this problem? Thanks in advance for any help.

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  • Bound Command not firing on another viewModel? What Am I doing wrong?

    - by devnet247
    Hi I cannot seem to bind a command to a button.I have a treeview on the left showing Country City etc.. And I tabcontrol on the right. do I This uses 4 viewModels rootviewModel-ContinentViewModel-CountryViewModel-CityViewModel What I am building is based on http://www.codeproject.com/KB/WPF/TreeViewWithViewModel.aspx Now on one of the tabs I have a Toolbar with a button "TestButton" that I have mapped in zaml. This does not fire! The reason is not firing is because I m binding the RootViewModel but the command that is bound in zaml is in the cityViewModel. How Do I pass the datacontext from one view to the other? or how do I make the button fire. I need the command to be in the cityViewModel. Any Suggestions on how I bind it? View "WorldExplorerView" where I bind the main DataContext public partial class WorldExplorerView { public WorldExplorerView() { InitializeComponent(); var continents = Database.GetContinents(); var rootViewModel = new RootViewModel(continents); DataContext = rootViewModel; } } CityViewModel public class CityViewModel : TreeViewItemViewModel { private City _city; private RelayCommand _testCommand; public CityViewModel(City city, CountryViewModel countryViewModel):base(countryViewModel,false) { _city = city; } Properties etc...... public ICommand TestCommand { get { if(_testCommand==null) { _testCommand = new RelayCommand(param => GetTestCommand(), param => CanCallTestCommand); ; } return _testCommand; } } protected bool CanCallTestCommand { get { return true; } } private static void GetTestCommand() { MessageBox.Show("It works"); } } ZAML <DockPanel> <DockPanel LastChildFill="True"> <Label DockPanel.Dock="top" Content="Title " HorizontalAlignment="Center"></Label> <StatusBar DockPanel.Dock="Bottom"> <StatusBarItem Content="Status Bar" ></StatusBarItem> </StatusBar> <Grid DockPanel.Dock="Top"> <Grid.ColumnDefinitions> <ColumnDefinition/> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="2*"/> </Grid.ColumnDefinitions> <TreeView Name="tree" ItemsSource="{Binding Continents}"> <TreeView.ItemContainerStyle> <Style TargetType="{x:Type TreeViewItem}"> <Setter Property="IsExpanded" Value="{Binding IsExpanded,Mode=TwoWay}"/> <Setter Property="IsSelected" Value="{Binding IsSelected,Mode=TwoWay}"/> <Setter Property="FontWeight" Value="Normal"/> <Style.Triggers> <Trigger Property="IsSelected" Value="True"> <Setter Property="FontWeight" Value="Bold"></Setter> </Trigger> </Style.Triggers> </Style> </TreeView.ItemContainerStyle> <TreeView.Resources> <HierarchicalDataTemplate DataType="{x:Type ViewModels:ContinentViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Continent.png"/> <TextBlock Text="{Binding ContinentName}"/> </StackPanel> </HierarchicalDataTemplate> <HierarchicalDataTemplate DataType="{x:Type ViewModels:CountryViewModel}" ItemsSource="{Binding Children}"> <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\Country.png"/> <TextBlock Text="{Binding CountryName}"/> </StackPanel> </HierarchicalDataTemplate> <DataTemplate DataType="{x:Type ViewModels:CityViewModel}" > <StackPanel Orientation="Horizontal"> <Image Width="16" Height="16" Margin="3,0" Source="Images\City.png"/> <TextBlock Text="{Binding CityName}"/> </StackPanel> </DataTemplate> </TreeView.Resources> </TreeView> <GridSplitter Grid.Row="0" Grid.Column="1" Background="LightGray" Width="5" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"/> <Grid Grid.Column="2" Margin="5" > <TabControl> <TabItem Header="Demo"> <DockPanel LastChildFill="True"> <ToolBar DockPanel.Dock="Top"> <!-- DOES NOT WORK--> <Button Name="btnTest" Command="{Binding TestCommand}" Content="Press me see if works"></Button> </ToolBar> <TextBox></TextBox> </DockPanel> </TabItem> <TabItem Header="Details" DataContext="{Binding Path=SelectedItem.City, ElementName=tree, Mode=OneWay}"> <StackPanel > <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityName}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Area}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding Population}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityDetailsInfo.ClubsCount}"/> <TextBlock VerticalAlignment="Center" FontSize="12" Text="{Binding CityDetailsInfo.PubsCount}"/> </StackPanel> </TabItem> </TabControl> </Grid> </Grid> </DockPanel> </DockPanel>

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  • C++ Mutexes and STL Lists Across Subclasses

    - by Genesis
    I am currently writing a multi-threaded C++ server using Poco and am now at the point where I need to be keeping information on which users are connected, how many connections each of them have, and given it is a proxy server, where each of those connections are proxying through to. For this purpose I have created a ServerStats class which holds an STL list of ServerUser objects. The ServerStats class includes functions which can add and remove objects from the list as well as find a user in the list an return a pointer to them so I can access member functions within any given ServerUser object in the list. The ServerUser class contains an STL list of ServerConnection objects and much like the ServerStats class it contains functions to add, remove and find elements within this list. Now all of the above is working but I am now trying to make it threadsafe. I have defined a Poco::FastMutex within the ServerStats class and can lock/unlock this in the appropriate places so that STL containers are not modified at the same time as being searched for example. I am however having an issue setting up mutexes within the ServerUser class and am getting the following compiler error: /root/poco/Foundation/include/Poco/Mutex.h: In copy constructor âServerUser::ServerUser(const ServerUser&)â: src/SocksServer.cpp:185: instantiated from âvoid __gnu_cxx::new_allocator<_Tp::construct(_Tp*, const _Tp&) [with _Tp = ServerUser]â /usr/include/c++/4.4/bits/stl_list.h:464: instantiated from âstd::_List_node<_Tp* std::list<_Tp, _Alloc::_M_create_node(const _Tp&) [with _Tp = ServerUser, _Alloc = std::allocator]â /usr/include/c++/4.4/bits/stl_list.h:1407: instantiated from âvoid std::list<_Tp, _Alloc::_M_insert(std::_List_iterator<_Tp, const _Tp&) [with _Tp = ServerUser, _Alloc = std::allocator]â /usr/include/c++/4.4/bits/stl_list.h:920: instantiated from âvoid std::list<_Tp, _Alloc::push_back(const _Tp&) [with _Tp = ServerUser, _Alloc = std::allocator]â src/SocksServer.cpp:301: instantiated from here /root/poco/Foundation/include/Poco/Mutex.h:164: error: âPoco::FastMutex::FastMutex(const Poco::FastMutex&)â is private src/SocksServer.cpp:185: error: within this context In file included from /usr/include/c++/4.4/x86_64-linux-gnu/bits/c++allocator.h:34, from /usr/include/c++/4.4/bits/allocator.h:48, from /usr/include/c++/4.4/string:43, from /root/poco/Foundation/include/Poco/Bugcheck.h:44, from /root/poco/Foundation/include/Poco/Foundation.h:147, from /root/poco/Net/include/Poco/Net/Net.h:45, from /root/poco/Net/include/Poco/Net/TCPServerParams.h:43, from src/SocksServer.cpp:1: /usr/include/c++/4.4/ext/new_allocator.h: In member function âvoid __gnu_cxx::new_allocator<_Tp::construct(_Tp*, const _Tp&) [with _Tp = ServerUser]â: /usr/include/c++/4.4/ext/new_allocator.h:105: note: synthesized method âServerUser::ServerUser(const ServerUser&)â first required here src/SocksServer.cpp: At global scope: src/SocksServer.cpp:118: warning: âstd::string getWord(std::string)â defined but not used make: * [/root/poco/SocksServer/obj/Linux/x86_64/debug_shared/SocksServer.o] Error 1 The code for the ServerStats, ServerUser and ServerConnection classes is below: class ServerConnection { public: bool continue_connection; int bytes_in; int bytes_out; string source_address; string destination_address; ServerConnection() { continue_connection = true; } ~ServerConnection() { } }; class ServerUser { public: string username; int connection_count; string client_ip; ServerUser() { } ~ServerUser() { } ServerConnection* addConnection(string source_address, string destination_address) { //FastMutex::ScopedLock lock(_connection_mutex); ServerConnection connection; connection.source_address = source_address; connection.destination_address = destination_address; client_ip = getWord(source_address, ":"); _connections.push_back(connection); connection_count++; return &_connections.back(); } void removeConnection(string source_address) { //FastMutex::ScopedLock lock(_connection_mutex); for(list<ServerConnection>::iterator it = _connections.begin(); it != _connections.end(); it++) { if(it->source_address == source_address) { it = _connections.erase(it); connection_count--; } } } void disconnect() { //FastMutex::ScopedLock lock(_connection_mutex); for(list<ServerConnection>::iterator it = _connections.begin(); it != _connections.end(); it++) { it->continue_connection = false; } } list<ServerConnection>* getConnections() { return &_connections; } private: list<ServerConnection> _connections; //UNCOMMENTING THIS LINE BREAKS IT: //mutable FastMutex _connection_mutex; }; class ServerStats { public: int current_users; ServerStats() { current_users = 0; } ~ServerStats() { } ServerUser* addUser(string username) { FastMutex::ScopedLock lock(_user_mutex); for(list<ServerUser>::iterator it = _users.begin(); it != _users.end(); it++) { if(it->username == username) { return &(*it); } } ServerUser newUser; newUser.username = username; _users.push_back(newUser); current_users++; return &_users.back(); } void removeUser(string username) { FastMutex::ScopedLock lock(_user_mutex); for(list<ServerUser>::iterator it = _users.begin(); it != _users.end(); it++) { if(it->username == username) { _users.erase(it); current_users--; break; } } } ServerUser* getUser(string username) { FastMutex::ScopedLock lock(_user_mutex); for(list<ServerUser>::iterator it = _users.begin(); it != _users.end(); it++) { if(it->username == username) { return &(*it); } } return NULL; } private: list<ServerUser> _users; mutable FastMutex _user_mutex; }; Now I have never used C++ for a project of this size or mutexes for that matter so go easy please :) Firstly, can anyone tell me why the above is causing a compiler error? Secondly, can anyone suggest a better way of storing the information I require? Bear in mind that I need to update this info whenever connections come or go and it needs to be global to the whole server.

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  • Get XML from Server for Use on Windows Phone

    - by psheriff
    When working with mobile devices you always need to take into account bandwidth usage and power consumption. If you are constantly connecting to a server to retrieve data for an input screen, then you might think about moving some of that data down to the phone and cache the data on the phone. An example would be a static list of US State Codes that you are asking the user to select from. Since this is data that does not change very often, this is one set of data that would be great to cache on the phone. Since the Windows Phone does not have an embedded database, you can just use an XML string stored in Isolated Storage. Of course, then you need to figure out how to get data down to the phone. You can either ship it with the application, or connect and retrieve the data from your server one time and thereafter cache it and retrieve it from the cache. In this blog post you will see how to create a WCF service to retrieve data from a Product table in a database and send that data as XML to the phone and store it in Isolated Storage. You will then read that data from Isolated Storage using LINQ to XML and display it in a ListBox. Step 1: Create a Windows Phone Application The first step is to create a Windows Phone application called WP_GetXmlFromDataSet (or whatever you want to call it). On the MainPage.xaml add the following XAML within the “ContentPanel” grid: <StackPanel>  <Button Name="btnGetXml"          Content="Get XML"          Click="btnGetXml_Click" />  <Button Name="btnRead"          Content="Read XML"          IsEnabled="False"          Click="btnRead_Click" />  <ListBox Name="lstData"            Height="430"            ItemsSource="{Binding}"            DisplayMemberPath="ProductName" /></StackPanel> Now it is time to create the WCF Service Application that you will call to get the XML from a table in a SQL Server database. Step 2: Create a WCF Service Application Add a new project to your solution called WP_GetXmlFromDataSet.Services. Delete the IService1.* and Service1.* files and the App_Data folder, as you don’t generally need these items. Add a new WCF Service class called ProductService. In the IProductService class modify the void DoWork() method with the following code: [OperationContract]string GetProductXml(); Open the code behind in the ProductService.svc and create the GetProductXml() method. This method (shown below) will connect up to a database and retrieve data from a Product table. public string GetProductXml(){  string ret = string.Empty;  string sql = string.Empty;  SqlDataAdapter da;  DataSet ds = new DataSet();   sql = "SELECT ProductId, ProductName,";  sql += " IntroductionDate, Price";  sql += " FROM Product";   da = new SqlDataAdapter(sql,    ConfigurationManager.ConnectionStrings["Sandbox"].ConnectionString);   da.Fill(ds);   // Create Attribute based XML  foreach (DataColumn col in ds.Tables[0].Columns)  {    col.ColumnMapping = MappingType.Attribute;  }   ds.DataSetName = "Products";  ds.Tables[0].TableName = "Product";  ret = ds.GetXml();   return ret;} After retrieving the data from the Product table using a DataSet, you will want to set each column’s ColumnMapping property to Attribute. Using attribute based XML will make the data transferred across the wire a little smaller. You then set the DataSetName property to the top-level element name you want to assign to the XML. You then set the TableName property on the DataTable to the name you want each element to be in your XML. The last thing you need to do is to call the GetXml() method on the DataSet object which will return an XML string of the data in your DataSet object. This is the value that you will return from the service call. The XML that is returned from the above call looks like the following: <Products>  <Product ProductId="1"           ProductName="PDSA .NET Productivity Framework"           IntroductionDate="9/3/2010"           Price="5000" />  <Product ProductId="3"           ProductName="Haystack Code Generator for .NET"           IntroductionDate="7/1/2010"           Price="599.00" />  ...  ...  ... </Products> The GetProductXml() method uses a connection string from the Web.Config file, so add a <connectionStrings> element to the Web.Config file in your WCF Service application. Modify the settings shown below as needed for your server and database name. <connectionStrings>  <add name="Sandbox"        connectionString="Server=Localhost;Database=Sandbox;                         Integrated Security=Yes"/></connectionStrings> The Product Table You will need a Product table that you can read data from. I used the following structure for my product table. Add any data you want to this table after you create it in your database. CREATE TABLE Product(  ProductId int PRIMARY KEY IDENTITY(1,1) NOT NULL,  ProductName varchar(50) NOT NULL,  IntroductionDate datetime NULL,  Price money NULL) Step 3: Connect to WCF Service from Windows Phone Application Back in your Windows Phone application you will now need to add a Service Reference to the WCF Service application you just created. Right-mouse click on the Windows Phone Project and choose Add Service Reference… from the context menu. Click on the Discover button. In the Namespace text box enter “ProductServiceRefrence”, then click the OK button. If you entered everything correctly, Visual Studio will generate some code that allows you to connect to your Product service. On the MainPage.xaml designer window double click on the Get XML button to generate the Click event procedure for this button. In the Click event procedure make a call to a GetXmlFromServer() method. This method will also need a “Completed” event procedure to be written since all communication with a WCF Service from Windows Phone must be asynchronous.  Write these two methods as follows: private const string KEY_NAME = "ProductData"; private void GetXmlFromServer(){  ProductServiceClient client = new ProductServiceClient();   client.GetProductXmlCompleted += new     EventHandler<GetProductXmlCompletedEventArgs>      (client_GetProductXmlCompleted);   client.GetProductXmlAsync();  client.CloseAsync();} void client_GetProductXmlCompleted(object sender,                                   GetProductXmlCompletedEventArgs e){  // Store XML data in Isolated Storage  IsolatedStorageSettings.ApplicationSettings[KEY_NAME] = e.Result;   btnRead.IsEnabled = true;} As you can see, this is a fairly standard call to a WCF Service. In the Completed event you get the Result from the event argument, which is the XML, and store it into Isolated Storage using the IsolatedStorageSettings.ApplicationSettings class. Notice the constant that I added to specify the name of the key. You will use this constant later to read the data from Isolated Storage. Step 4: Create a Product Class Even though you stored XML data into Isolated Storage when you read that data out you will want to convert each element in the XML file into an actual Product object. This means that you need to create a Product class in your Windows Phone application. Add a Product class to your project that looks like the code below: public class Product{  public string ProductName{ get; set; }  public int ProductId{ get; set; }  public DateTime IntroductionDate{ get; set; }  public decimal Price{ get; set; }} Step 5: Read Settings from Isolated Storage Now that you have the XML data stored in Isolated Storage, it is time to use it. Go back to the MainPage.xaml design view and double click on the Read XML button to generate the Click event procedure. From the Click event procedure call a method named ReadProductXml().Create this method as shown below: private void ReadProductXml(){  XElement xElem = null;   if (IsolatedStorageSettings.ApplicationSettings.Contains(KEY_NAME))  {    xElem = XElement.Parse(     IsolatedStorageSettings.ApplicationSettings[KEY_NAME].ToString());     // Create a list of Product objects    var products =         from prod in xElem.Descendants("Product")        orderby prod.Attribute("ProductName").Value        select new Product        {          ProductId = Convert.ToInt32(prod.Attribute("ProductId").Value),          ProductName = prod.Attribute("ProductName").Value,          IntroductionDate =             Convert.ToDateTime(prod.Attribute("IntroductionDate").Value),          Price = Convert.ToDecimal(prod.Attribute("Price").Value)        };     lstData.DataContext = products;  }} The ReadProductXml() method checks to make sure that the key name that you saved your XML as exists in Isolated Storage prior to trying to open it. If the key name exists, then you retrieve the value as a string. Use the XElement’s Parse method to convert the XML string to a XElement object. LINQ to XML is used to iterate over each element in the XElement object and create a new Product object from each attribute in your XML file. The LINQ to XML code also orders the XML data by the ProductName. After the LINQ to XML code runs you end up with an IEnumerable collection of Product objects in the variable named “products”. You assign this collection of product data to the DataContext of the ListBox you created in XAML. The DisplayMemberPath property of the ListBox is set to “ProductName” so it will now display the product name for each row in your products collection. Summary In this article you learned how to retrieve an XML string from a table in a database, return that string across a WCF Service and store it into Isolated Storage on your Windows Phone. You then used LINQ to XML to create a collection of Product objects from the data stored and display that data in a Windows Phone list box. This same technique can be used in Silverlight or WPF applications too. NOTE: You can download the complete sample code at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "Get XML From Server for Use on Windows Phone" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free video on Silverlight entitled Silverlight XAML for the Complete Novice - Part 1.  

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  • implement N-Tier Entity Framework 4.0 with DTOs

    - by kathy
    Hi, I'm currently building a web based system and trying to implement N-Tier Entity Framework 4.0 with DTOs in a SOA Architecture. I am having a problem understanding how I should implement the Data Access Layer (DAL) , the Business Logic Layer (BLL) and the Presentation Layer. Let’s suppose that I have a “useraccount” entity has the following : Id FirstName LastName AuditFields_InsertDate AuditFields_UpdateDate In the DAL I created a class “UserAccountsData.cs” as the following : using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace OrderSystemDAL { public static class UserAccountsData { public static int Insert(string firstName, string lastName, DateTime insertDate) { using (OrderSystemEntities db = new OrderSystemEntities()) { return Insert(db, firstName, lastName, insertDate); } } public static int Insert(OrderSystemEntities db, string firstName, string lastName, DateTime insertDate) { return db.UserAccounts_Insert(firstName, lastName, insertDate, insertDate).ElementAt(0).Value; } public static void Update(int id, string firstName, string lastName, DateTime updateDate) { using (OrderSystemEntities db = new OrderSystemEntities()) { Update(db, id, firstName, lastName, updateDate); } } public static void Update(OrderSystemEntities db, int id, string firstName, string lastName, DateTime updateDate) { db.UserAccounts_Update(id, firstName, lastName, updateDate); } public static void Delete(int id) { using (OrderSystemEntities db = new OrderSystemEntities()) { Delete(db, id); } } public static void Delete(OrderSystemEntities db, int id) { db.UserAccounts_Delete(id); } public static UserAccount SelectById(int id) { using (OrderSystemEntities db = new OrderSystemEntities()) { return SelectById(db, id); } } public static UserAccount SelectById(OrderSystemEntities db, int id) { return db.UserAccounts_SelectById(id).ElementAtOrDefault(0); } public static List<UserAccount> SelectAll() { using (OrderSystemEntities db = new OrderSystemEntities()) { return SelectAll(db); } } public static List<UserAccount> SelectAll(OrderSystemEntities db) { return db.UserAccounts_SelectAll().ToList(); } } } And in the BLL I created a class “UserAccountEO.cs” as the following : using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Collections; using OrderSystemDAL; namespace OrderSystemBLL { public class UserAccountEO { public int Id { get; set; } public string FirstName { get; set; } public string LastName { get; set; } public DateTime InsertDate { get; set; } public DateTime UpdateDate { get; set; } public string FullName { get { return LastName + ", " + FirstName; } } public bool Save(ref ArrayList validationErrors) { ValidateSave(ref validationErrors); if (validationErrors.Count == 0) { if (Id == 0) { Id = UserAccountsData.Insert(FirstName, LastName, DateTime.Now); } else { UserAccountsData.Update(Id, FirstName, LastName, DateTime.Now); } return true; } else { return false; } } private void ValidateSave(ref ArrayList validationErrors) { if (FirstName.Trim() == "") { validationErrors.Add("The First Name is required."); } if (LastName.Trim() == "") { validationErrors.Add("The Last Name is required."); } } public void Delete(ref ArrayList validationErrors) { ValidateDelete(ref validationErrors); if (validationErrors.Count == 0) { UserAccountsData.Delete(Id); } } private void ValidateDelete(ref ArrayList validationErrors) { //Check for referential integrity. } public bool Select(int id) { UserAccount userAccount = UserAccountsData.SelectById(id); if (userAccount != null) { MapData(userAccount); return true; } else { return false; } } internal void MapData(UserAccount userAccount) { Id = userAccount.Id; FirstName = userAccount.FristName; LastName = userAccount.LastName; InsertDate = userAccount.AuditFields_InsertDate; UpdateDate = userAccount.AuditFields_UpdateDate; } public static List<UserAccountEO> SelectAll() { List<UserAccountEO> userAccounts = new List<UserAccountEO>(); List<UserAccount> userAccountDTOs = UserAccountsData.SelectAll(); foreach (UserAccount userAccountDTO in userAccountDTOs) { UserAccountEO userAccountEO = new UserAccountEO(); userAccountEO.MapData(userAccountDTO); userAccounts.Add(userAccountEO); } return userAccounts; } } } And in the PL I created a webpage as the following : using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using OrderSystemBLL; using System.Collections; namespace OrderSystemUI { public partial class Users : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { LoadUserDropDownList(); } } private void LoadUserDropDownList() { ddlUsers.DataSource = UserAccountEO.SelectAll(); ddlUsers.DataTextField = "FullName"; ddlUsers.DataValueField = "Id"; ddlUsers.DataBind(); } } } Is the above way the right way to Implement the DTOs pattern in n-tier Architecture using EF4 ??? I would appreciate your help Thanks.

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  • Error Creating RSS Feed XML file - Java

    - by GigaPr
    Hi, i am trying to create an RssFeed using java this is the class i use import com.rssFeed.domain.RSS; import com.rssFeed.domain.RSSItem; import java.io.FileOutputStream; import java.util.Iterator; import javax.xml.stream.XMLEventFactory; import javax.xml.stream.XMLEventWriter; import javax.xml.stream.XMLOutputFactory; import javax.xml.stream.XMLStreamException; import javax.xml.stream.events.Characters; import javax.xml.stream.events.EndElement; import javax.xml.stream.events.StartDocument; import javax.xml.stream.events.StartElement; import javax.xml.stream.events.XMLEvent; public class RssBuilder { private static String XML_BLOCK = "\n"; private static String XML_INDENT = "\t"; public static void BuildRss(RSS rss, String xmlfile) throws Exception { XMLOutputFactory output = XMLOutputFactory.newInstance(); XMLEventWriter writer = output.createXMLEventWriter(new FileOutputStream(xmlfile)); try { XMLEventFactory eventFactory = XMLEventFactory.newInstance(); XMLEvent endSection = eventFactory.createDTD(XML_BLOCK); StartDocument startDocument = eventFactory.createStartDocument(); writer.add(startDocument); writer.add(endSection); StartElement rssStart = eventFactory.createStartElement("", "", "rss"); writer.add(rssStart); writer.add(eventFactory.createAttribute("version", "2.0")); writer.add(endSection); writer.add(eventFactory.createStartElement("", "", "channel")); writer.add(endSection); createNode(writer, "title", rss.getTitle()); createNode(writer, "description", rss.getDescription()); createNode(writer, "link", rss.getLink()); createNode(writer, "dateCreated", rss.getDateCreated().toString()); createNode(writer, "language", rss.getLanguage()); createNode(writer, "pubDate", rss.getPubDate().toString()); createNode(writer, "dateModified", rss.getDateModified().toString()); createNode(writer, "dateModified", rss.getDateModified().toString()); createNode(writer, "pubDate", rss.getPubDate().toString()); createNode(writer, "lastBuildDate", rss.getLastBuildDate().toString()); createNode(writer, "language", rss.getLanguage().toString()); createNode(writer, "rating", rss.getRating().toString()); Iterator<RSSItem> iterator = rss.getRssItems().iterator(); while (iterator.hasNext()) { RSSItem entry = iterator.next(); writer.add(eventFactory.createStartElement("", "", "item")); writer.add(endSection); createNode(writer, "title", entry.getTitle()); createNode(writer, "description", entry.getDescription()); createNode(writer, "link", entry.getLink()); createNode(writer, "dateCreated", entry.getDateCreated().toString()); createNode(writer, "pubDate", entry.getDateModified().toString()); writer.add(eventFactory.createEndElement("", "", "item")); writer.add(endSection); } writer.add(endSection); writer.add(eventFactory.createEndElement("", "", "channel")); writer.add(endSection); writer.add(eventFactory.createEndElement("", "", "rss")); writer.add(endSection); writer.add(eventFactory.createEndDocument()); writer.close(); } catch(Exception e) { writer.close(); } } private static void createNode(XMLEventWriter eventWriter, String name, String value)throws XMLStreamException { XMLEventFactory eventFactory = XMLEventFactory.newInstance(); XMLEvent endSection = eventFactory.createDTD(XML_BLOCK); XMLEvent tabSection = eventFactory.createDTD(XML_INDENT); StartElement sElement = eventFactory.createStartElement("", "", name); eventWriter.add(tabSection); eventWriter.add(sElement); Characters characters = eventFactory.createCharacters(value); eventWriter.add(characters); EndElement eElement = eventFactory.createEndElement("", "", name); eventWriter.add(eElement); eventWriter.add(endSection); } } But i get the following error type Exception report message descriptionThe server encountered an internal error () that prevented it from fulfilling this request. exception org.springframework.web.util.NestedServletException: Request processing failed; nested exception is javax.xml.stream.XMLStreamException: Can not write DOCTYPE declaration (DTD) when not in prolog any more (state 2; start element(s) written) root cause javax.xml.stream.XMLStreamException: Can not write DOCTYPE declaration (DTD) when not in prolog any more (state 2; start element(s) written) what does it mean?

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  • How to implement drag and drop in Flex Grid control?

    - by Bogdan
    I have a simple Grid control with some buttons that I want to be able to move around. The code below does work, but it takes a lot of effort to actually do the drag&drop and it is not clear where the drop will happen. I have to move the mouse around a lot to get to a state where the drop is not rejected. I would appreciate any suggestions on how to make this more "user friendly". <?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="vertical" verticalAlign="middle" horizontalAlign="center" height="200" width="200"> <mx:Script> <![CDATA[ import mx.containers.GridItem; import mx.controls.Button; import mx.core.DragSource; import mx.events.*; import mx.managers.DragManager; private function dragInit(event:MouseEvent):void { if(event.buttonDown) { var button:Button = event.currentTarget as Button; var dragSource:DragSource = new DragSource(); dragSource.addData(button, 'button'); DragManager.doDrag(button, dragSource, event); } } private function dragEnter(event:DragEvent): void { var target:GridItem = event.currentTarget as GridItem; if (event.dragSource.hasFormat('button') && target.getChildren().length == 0) { DragManager.acceptDragDrop(target); DragManager.showFeedback(DragManager.MOVE); } } private function dragDrop(event:DragEvent): void { var target:GridItem = event.currentTarget as GridItem; var button:Button = event.dragSource.dataForFormat('button') as Button; target.addChild(button); } ]]> </mx:Script> <mx:Grid> <mx:GridRow width="100%" height="100%"> <mx:GridItem width="44" height="44" dragEnter="dragEnter(event)" dragDrop="dragDrop(event)"> </mx:GridItem> <mx:GridItem width="44" height="44" dragEnter="dragEnter(event)" dragDrop="dragDrop(event)"> </mx:GridItem> <mx:GridItem width="44" height="44" dragEnter="dragEnter(event)" dragDrop="dragDrop(event)"> <mx:Button label="A" width="40" height="40" mouseMove="dragInit(event)"/> </mx:GridItem> </mx:GridRow> <mx:GridRow width="100%" height="100%"> <mx:GridItem width="44" height="44" dragEnter="dragEnter(event)" dragDrop="dragDrop(event)"> </mx:GridItem> <mx:GridItem width="44" height="44" dragEnter="dragEnter(event)" dragDrop="dragDrop(event)"> <mx:Button label="B" width="40" height="40" mouseMove="dragInit(event)"/> </mx:GridItem> <mx:GridItem width="44" height="44" dragEnter="dragEnter(event)" dragDrop="dragDrop(event)"> </mx:GridItem> </mx:GridRow> <mx:GridRow width="100%" height="100%"> <mx:GridItem width="44" height="44" dragEnter="dragEnter(event)" dragDrop="dragDrop(event)"> <mx:Button label="C" width="40" height="40" mouseMove="dragInit(event)"/> </mx:GridItem> <mx:GridItem width="44" height="44" dragEnter="dragEnter(event)" dragDrop="dragDrop(event)"> </mx:GridItem> <mx:GridItem width="44" height="44" dragEnter="dragEnter(event)" dragDrop="dragDrop(event)"> </mx:GridItem> </mx:GridRow> </mx:Grid> <mx:Style> GridItem { borderColor: #A09999; borderStyle: solid; borderThickness: 2; horizontal-align: center; vertical-align: center; } Grid { borderColor: #A09999; borderStyle: solid; borderThickness: 2; horizontalGap: 0; verticalGap: 0; horizontal-align: center; vertical-align: center; } </mx:Style> </mx:Application>

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  • Understanding C# async / await (1) Compilation

    - by Dixin
    Now the async / await keywords are in C#. Just like the async and ! in F#, this new C# feature provides great convenience. There are many nice documents talking about how to use async / await in specific scenarios, like using async methods in ASP.NET 4.5 and in ASP.NET MVC 4, etc. In this article we will look at the real code working behind the syntax sugar. According to MSDN: The async modifier indicates that the method, lambda expression, or anonymous method that it modifies is asynchronous. Since lambda expression / anonymous method will be compiled to normal method, we will focus on normal async method. Preparation First of all, Some helper methods need to make up. internal class HelperMethods { internal static int Method(int arg0, int arg1) { // Do some IO. WebClient client = new WebClient(); Enumerable.Repeat("http://weblogs.asp.net/dixin", 10) .Select(client.DownloadString).ToArray(); int result = arg0 + arg1; return result; } internal static Task<int> MethodTask(int arg0, int arg1) { Task<int> task = new Task<int>(() => Method(arg0, arg1)); task.Start(); // Hot task (started task) should always be returned. return task; } internal static void Before() { } internal static void Continuation1(int arg) { } internal static void Continuation2(int arg) { } } Here Method() is a long running method doing some IO. Then MethodTask() wraps it into a Task and return that Task. Nothing special here. Await something in async method Since MethodTask() returns Task, let’s try to await it: internal class AsyncMethods { internal static async Task<int> MethodAsync(int arg0, int arg1) { int result = await HelperMethods.MethodTask(arg0, arg1); return result; } } Because we used await in the method, async must be put on the method. Now we get the first async method. According to the naming convenience, it is called MethodAsync. Of course a async method can be awaited. So we have a CallMethodAsync() to call MethodAsync(): internal class AsyncMethods { internal static async Task<int> CallMethodAsync(int arg0, int arg1) { int result = await MethodAsync(arg0, arg1); return result; } } After compilation, MethodAsync() and CallMethodAsync() becomes the same logic. This is the code of MethodAsyc(): internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MethodAsync(int arg0, int arg1) { MethodAsyncStateMachine methodAsyncStateMachine = new MethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; methodAsyncStateMachine.Builder.Start(ref methodAsyncStateMachine); return methodAsyncStateMachine.Builder.Task; } } It just creates and starts a state machine MethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Result; private TaskAwaiter<int> awaitor; void IAsyncStateMachine.MoveNext() { try { if (this.State != 0) { this.awaitor = HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaitor.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaitor, ref this); return; } } else { this.State = -1; } this.Result = this.awaitor.GetResult(); } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); return; } this.State = -2; this.Builder.SetResult(this.Result); } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine param0) { this.Builder.SetStateMachine(param0); } } The generated code has been cleaned up so it is readable and can be compiled. Several things can be observed here: The async modifier is gone, which shows, unlike other modifiers (e.g. static), there is no such IL/CLR level “async” stuff. It becomes a AsyncStateMachineAttribute. This is similar to the compilation of extension method. The generated state machine is very similar to the state machine of C# yield syntax sugar. The local variables (arg0, arg1, result) are compiled to fields of the state machine. The real code (await HelperMethods.MethodTask(arg0, arg1)) is compiled into MoveNext(): HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(). CallMethodAsync() will create and start its own state machine CallMethodAsyncStateMachine: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(CallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> CallMethodAsync(int arg0, int arg1) { CallMethodAsyncStateMachine callMethodAsyncStateMachine = new CallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; callMethodAsyncStateMachine.Builder.Start(ref callMethodAsyncStateMachine); return callMethodAsyncStateMachine.Builder.Task; } } CallMethodAsyncStateMachine has the same logic as MethodAsyncStateMachine above. The detail of the state machine will be discussed soon. Now it is clear that: async /await is a C# level syntax sugar. There is no difference to await a async method or a normal method. A method returning Task will be awaitable. State machine and continuation To demonstrate more details in the state machine, a more complex method is created: internal class AsyncMethods { internal static async Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; } } In this method: There are multiple awaits. There are code before the awaits, and continuation code after each await After compilation, this multi-await method becomes the same as above single-await methods: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; multiCallMethodAsyncStateMachine.Builder.Start(ref multiCallMethodAsyncStateMachine); return multiCallMethodAsyncStateMachine.Builder.Task; } } It creates and starts one single state machine, MultiCallMethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Arg2; public int Arg3; public int ResultOfAwait1; public int ResultOfAwait2; public int ResultToReturn; private TaskAwaiter<int> awaiter; void IAsyncStateMachine.MoveNext() { try { switch (this.State) { case -1: HelperMethods.Before(); this.awaiter = AsyncMethods.MethodAsync(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 0: this.ResultOfAwait1 = this.awaiter.GetResult(); HelperMethods.Continuation1(this.ResultOfAwait1); this.awaiter = AsyncMethods.MethodAsync(this.Arg2, this.Arg3).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 1; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 1: this.ResultOfAwait2 = this.awaiter.GetResult(); HelperMethods.Continuation2(this.ResultOfAwait2); this.ResultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; this.State = -2; this.Builder.SetResult(this.ResultToReturn); break; } } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); } } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine) { this.Builder.SetStateMachine(stateMachine); } } The above code is already cleaned up, but there are still a lot of things. More clean up can be done, and the state machine can be very simple: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { // State: // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End public int State; public TaskCompletionSource<int> ResultToReturn; // int resultToReturn ... public int Arg0; // int Arg0 public int Arg1; // int arg1 public int Arg2; // int arg2 public int Arg3; // int arg3 public int ResultOfAwait1; // int resultOfAwait1 ... public int ResultOfAwait2; // int resultOfAwait2 ... private Task<int> currentTaskToAwait; /// <summary> /// Moves the state machine to its next state. /// </summary> void IAsyncStateMachine.MoveNext() { try { switch (this.State) { // Orginal code is splitted by "case"s: // case -1: // HelperMethods.Before(); // MethodAsync(Arg0, arg1); // case 0: // int resultOfAwait1 = await ... // HelperMethods.Continuation1(resultOfAwait1); // MethodAsync(arg2, arg3); // case 1: // int resultOfAwait2 = await ... // HelperMethods.Continuation2(resultOfAwait2); // int resultToReturn = resultOfAwait1 + resultOfAwait2; // return resultToReturn; case -1: // -1 is begin. HelperMethods.Before(); // Code before 1st await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg0, this.Arg1); // 1st task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 0. this.State = 0; IAsyncStateMachine this1 = this; // Cannot use "this" in lambda so create a local variable. this.currentTaskToAwait.ContinueWith(_ => this1.MoveNext()); // Callback break; case 0: // Now 1st await is done. this.ResultOfAwait1 = this.currentTaskToAwait.Result; // Get 1st await's result. HelperMethods.Continuation1(this.ResultOfAwait1); // Code after 1st await and before 2nd await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg2, this.Arg3); // 2nd task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 1. this.State = 1; IAsyncStateMachine this2 = this; // Cannot use "this" in lambda so create a local variable. this.currentTaskToAwait.ContinueWith(_ => this2.MoveNext()); // Callback break; case 1: // Now 2nd await is done. this.ResultOfAwait2 = this.currentTaskToAwait.Result; // Get 2nd await's result. HelperMethods.Continuation2(this.ResultOfAwait2); // Code after 2nd await. int resultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; // Code after 2nd await. // End with resultToReturn. this.State = -2; // -2 is end. this.ResultToReturn.SetResult(resultToReturn); break; } } catch (Exception exception) { // End with exception. this.State = -2; // -2 is end. this.ResultToReturn.SetException(exception); } } /// <summary> /// Configures the state machine with a heap-allocated replica. /// </summary> /// <param name="stateMachine">The heap-allocated replica.</param> [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine) { // No core logic. } } Only Task and TaskCompletionSource are involved in this version. And MultiCallMethodAsync() can be simplified to: [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync_(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, ResultToReturn = new TaskCompletionSource<int>(), // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End State = -1 }; (multiCallMethodAsyncStateMachine as IAsyncStateMachine).MoveNext(); // Original code are in this method. return multiCallMethodAsyncStateMachine.ResultToReturn.Task; } Now the whole state machine becomes very clear - it is about callback: Original code are split into pieces by “await”s, and each piece is put into each “case” in the state machine. Here the 2 awaits split the code into 3 pieces, so there are 3 “case”s. The “piece”s are chained by callback, that is done by Builder.AwaitUnsafeOnCompleted(callback), or currentTaskToAwait.ContinueWith(callback) in the simplified code. A previous “piece” will end with a Task (which is to be awaited), when the task is done, it will callback the next “piece”. The state machine’s state works with the “case”s to ensure the code “piece”s executes one after another. Callback Since it is about callback, the simplification  can go even further – the entire state machine can be completely purged. Now MultiCallMethodAsync() becomes: internal static Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { TaskCompletionSource<int> taskCompletionSource = new TaskCompletionSource<int>(); try { // Oringinal code begins. HelperMethods.Before(); MethodAsync(arg0, arg1).ContinueWith(await1 => { int resultOfAwait1 = await1.Result; HelperMethods.Continuation1(resultOfAwait1); MethodAsync(arg2, arg3).ContinueWith(await2 => { int resultOfAwait2 = await2.Result; HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; // Oringinal code ends. taskCompletionSource.SetResult(resultToReturn); }); }); } catch (Exception exception) { taskCompletionSource.SetException(exception); } return taskCompletionSource.Task; } Please compare with the original async / await code: HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; Yeah that is the magic of C# async / await: Await is literally pretending to wait. In a await expression, a Task object will be return immediately so that caller is not blocked. The continuation code is compiled as that Task’s callback code. When that task is done, continuation code will execute. Please notice that many details inside the state machine are omitted for simplicity, like context caring, etc. If you want to have a detailed picture, please do check out the source code of AsyncTaskMethodBuilder and TaskAwaiter.

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  • Android app in eclipse

    - by Colin
    Hello everybody, i've searched for days but cant find an answer, perhaps you guys can help. I'm creating an android app in eclipse, it all works just one thing is bugging me. this is my main.java: package com.test; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Toast; public class Main extends Activity implements OnClickListener { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Add Click listeners for all buttons View firstButton = findViewById(R.id.btn_rassen); firstButton.setOnClickListener(this); View secondButton = findViewById(R.id.button2); secondButton.setOnClickListener(this); } // Process the button click events @Override public void onClick(View v) { switch(v.getId()){ case R.id.btn_rassen: Intent j = new Intent(this, Webscreen.class); j.putExtra(com.test.Webscreen.URL, "http://www.google.com/"); startActivity(j); break; case R.id.button2: Intent k = new Intent(this, Webscreen.class); k.putExtra(com.test.Webscreen.URL, "http://notworkingurltotest.com"); startActivity(k); break; } } } now when it calls the webview.java the page called shows up but not the buttons i created in the layout xml page. does anybody have any idea why this is? your help is much appreciated! ohw this is my webscreen.java package com.test; import android.app.Activity; import android.app.AlertDialog; import android.app.ProgressDialog; import android.content.DialogInterface; import android.content.Intent; import android.net.Uri; import android.os.Bundle; import android.util.Log; import android.view.Window; import android.webkit.WebSettings; import android.webkit.WebView; import android.webkit.WebViewClient; import android.widget.Toast; public class Webscreen extends Activity { public static final String URL = ""; private static final String TAG = "WebscreenClass"; private WebView webview; private ProgressDialog progressDialog; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.webscreen); this.getIntent().getExtras(); this.webview = (WebView) findViewById(R.string.webview); String turl = getIntent().getStringExtra(URL); Log.i(TAG, " URL = "+turl); WebView webview = new WebView(this); setContentView(webview); final Activity activity = this; webview.setWebViewClient(new WebViewClient() { public boolean shouldOverrideUrlLoading(WebView view, String url) { view.loadUrl(url); return true; } public void onLoadResource (WebView view, String url) { if (progressDialog == null) { progressDialog = new ProgressDialog(activity); progressDialog.setMessage("Bezig met laden..."); progressDialog.show(); } } public void onPageFinished(WebView view, String url) { if (progressDialog.isShowing()) { progressDialog.dismiss(); progressDialog = null; } } public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) { Intent myIntent = new Intent(); myIntent.setClassName("com.test", "com.test.Main"); startActivity(myIntent); Toast.makeText(activity, "Laden van onderdeel mislukt, probeer het later nog eens! ", Toast.LENGTH_LONG).show(); progressDialog.show(); } }); webview.loadUrl(turl); } } webscreen.xml layout: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <!-- <1> --> <LinearLayout android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content"> <EditText android:id="@+id/url" android:layout_height="wrap_content" android:layout_width="wrap_content" android:lines="1" android:layout_weight="1.0" android:hint="http://" android:visibility="visible" /> <Button android:id="@+id/go_button" android:layout_height="wrap_content" android:layout_width="wrap_content" android:text="go_button" /> </LinearLayout> <!-- <2> --> <WebView android:id="@string/webview" android:layout_width="fill_parent" android:layout_height="0dip" /> </LinearLayout>

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  • java.sql.SQLException: Operation not allowed after ResultSet closed

    - by javatraniee
    Why am I getting an Resultset already closed error? public class Server implements Runnable { private static int port = 1600, maxConnections = 0; public static Connection connnew = null; public static Connection connnew1 = null; public static Statement stnew, stnew1, stnew2, stnew3, stnew4; public void getConnection() { try { Class.forName("org.gjt.mm.mysql.Driver"); connnew = DriverManager.getConnection("jdbc:mysql://localhost/db_alldata", "root", "flashkit"); connnew1 = DriverManager.getConnection("jdbc:mysql://localhost/db_main", "root", "flashkit"); stnew = connnew.createStatement(); stnew1 = connnew.createStatement(); stnew2 = connnew1.createStatement(); stnew3 = connnew1.createStatement(); stnew4 = connnew1.createStatement(); } catch (Exception e) { System.out.print("Get Connection Exception---" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + "----- > " + e); } } public void closeConnection() { try { if (!(connnew.isClosed())) { stnew.close(); stnew1.close(); connnew.close(); } if (!(connnew1.isClosed())) { stnew2.close(); stnew3.close(); stnew4.close(); connnew1.close(); } } catch (Exception e) { System.out.print("Close Connection Closing Exception-----" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + "------->" + e); } } Server() { try { } catch (Exception ee) { System.out.print("Server Exceptions in main connection--" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + "------>" + ee); } } public static void main(String[] args) throws SQLException { int i = 0; Server STUD = new Server(); STUD.getConnection(); try { ServerSocket listener = new ServerSocket(port); Socket server; while ((i++ < maxConnections) || (maxConnections == 0)) { @SuppressWarnings("unused") doComms connection; server = listener.accept(); try { ResultSet checkconnection = stnew4 .executeQuery("select count(*) from t_studentdetails"); if (checkconnection.next()) { // DO NOTHING IF EXCEPTION THEN CLOSE ALL CONNECTIONS AND OPEN NEW // CONNECTIONS } } catch (Exception e) { System.out.print("Db Connection Lost Closing And Re-Opning It--------" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + "--------" + e); STUD.closeConnection(); STUD.getConnection(); } doComms conn_c = new doComms(server, stnew, stnew1, stnew2, stnew3); Thread t = new Thread(conn_c); t.start(); } } catch (IOException ioe) { System.out.println("Main IOException on socket listen: " + ioe); } } public void run() { } } class doComms implements Runnable { private Socket server; private String input; static Connection conn = null; static Connection conn1 = null; static Statement st, st1, st2, st3; doComms(Socket server, Statement st, Statement st1, Statement st2, Statement st3) { this.server = server; doComms.st = st; doComms.st1 = st1; doComms.st2 = st2; doComms.st3 = st3; } @SuppressWarnings("deprecation") public void run() { input = ""; // char ch; try { DataInputStream in = new DataInputStream(server.getInputStream()); OutputStreamWriter outgoing = new OutputStreamWriter(server.getOutputStream()); while (!(null == (input = in.readLine()))) { savetodatabase(input, server.getPort(), outgoing); } } catch (IOException ioe) { System.out.println("RUN IOException on socket listen:-------" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + "----- " + ioe); ioe.printStackTrace(); } } public void savetodatabase(String line, int port1, OutputStreamWriter outgoing) { try { String Rollno = "-", name = "-", div = "-", storeddate = "-", storedtime = "-", mailfrom = ""; String newline = line; String unitid = "-"; storeddate = new SimpleDateFormat("yyyy-MM-dd").format(new java.util.Date()); storedtime = new SimpleDateFormat("HH:mm:ss").format(new java.util.Date()); String sql2 = "delete from t_currentport where PortNumber='" + port1 + "''"; st2.executeUpdate(sql2); sql2 = "insert into t_currentport (unitid, portnumber,thedate,thetime) values >('" + unitid + "','" + port1 + "','" + storeddate + "','" + storedtime + "')"; st2.executeUpdate(sql2); String tablename = GetTable(); String sql = "select * from t_studentdetails where Unitid='" + unitid + "'"; ResultSet rst = st2.executeQuery(sql); if (rst.next()) { Rollno = rst.getString("Rollno"); name = rst.getString("name"); div = rst.getString("div"); } String sql1 = "insert into studentInfo StoredDate,StoredTime,Subject,UnitId,Body,Status,Rollno,div,VehId,MailDate,MailTime,MailFrom,MailTo,Header,UnProcessedStamps) values('" + storeddate + "','" + storedtime + "','" + unitid + "','" + unitid + "','" + newline + "','Pending','" + Rollno + "','" + div + "','" + name + "','" + storeddate + "','" + storedtime + "','" + mailfrom + "','" + mailfrom + "','-','-')"; st1.executeUpdate(sql1); } catch (Exception e) { System.out.print("Save to db Connection Exception--" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()) + "-->" + e); } } }

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  • Understanding C# async / await (1) Compilation

    - by Dixin
    Now the async / await keywords are in C#. Just like the async and ! in F#, this new C# feature provides great convenience. There are many nice documents talking about how to use async / await in specific scenarios, like using async methods in ASP.NET 4.5 and in ASP.NET MVC 4, etc. In this article we will look at the real code working behind the syntax sugar. According to MSDN: The async modifier indicates that the method, lambda expression, or anonymous method that it modifies is asynchronous. Since lambda expression / anonymous method will be compiled to normal method, we will focus on normal async method. Preparation First of all, Some helper methods need to make up. internal class HelperMethods { internal static int Method(int arg0, int arg1) { // Do some IO. WebClient client = new WebClient(); Enumerable.Repeat("http://weblogs.asp.net/dixin", 10) .Select(client.DownloadString).ToArray(); int result = arg0 + arg1; return result; } internal static Task<int> MethodTask(int arg0, int arg1) { Task<int> task = new Task<int>(() => Method(arg0, arg1)); task.Start(); // Hot task (started task) should always be returned. return task; } internal static void Before() { } internal static void Continuation1(int arg) { } internal static void Continuation2(int arg) { } } Here Method() is a long running method doing some IO. Then MethodTask() wraps it into a Task and return that Task. Nothing special here. Await something in async method Since MethodTask() returns Task, let’s try to await it: internal class AsyncMethods { internal static async Task<int> MethodAsync(int arg0, int arg1) { int result = await HelperMethods.MethodTask(arg0, arg1); return result; } } Because we used await in the method, async must be put on the method. Now we get the first async method. According to the naming convenience, it is named MethodAsync. Of course a async method can be awaited. So we have a CallMethodAsync() to call MethodAsync(): internal class AsyncMethods { internal static async Task<int> CallMethodAsync(int arg0, int arg1) { int result = await MethodAsync(arg0, arg1); return result; } } After compilation, MethodAsync() and CallMethodAsync() becomes the same logic. This is the code of MethodAsyc(): internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MethodAsync(int arg0, int arg1) { MethodAsyncStateMachine methodAsyncStateMachine = new MethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; methodAsyncStateMachine.Builder.Start(ref methodAsyncStateMachine); return methodAsyncStateMachine.Builder.Task; } } It just creates and starts a state machine, MethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Result; private TaskAwaiter<int> awaitor; void IAsyncStateMachine.MoveNext() { try { if (this.State != 0) { this.awaitor = HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaitor.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaitor, ref this); return; } } else { this.State = -1; } this.Result = this.awaitor.GetResult(); } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); return; } this.State = -2; this.Builder.SetResult(this.Result); } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine param0) { this.Builder.SetStateMachine(param0); } } The generated code has been refactored, so it is readable and can be compiled. Several things can be observed here: The async modifier is gone, which shows, unlike other modifiers (e.g. static), there is no such IL/CLR level “async” stuff. It becomes a AsyncStateMachineAttribute. This is similar to the compilation of extension method. The generated state machine is very similar to the state machine of C# yield syntax sugar. The local variables (arg0, arg1, result) are compiled to fields of the state machine. The real code (await HelperMethods.MethodTask(arg0, arg1)) is compiled into MoveNext(): HelperMethods.MethodTask(this.Arg0, this.Arg1).GetAwaiter(). CallMethodAsync() will create and start its own state machine CallMethodAsyncStateMachine: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(CallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> CallMethodAsync(int arg0, int arg1) { CallMethodAsyncStateMachine callMethodAsyncStateMachine = new CallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; callMethodAsyncStateMachine.Builder.Start(ref callMethodAsyncStateMachine); return callMethodAsyncStateMachine.Builder.Task; } } CallMethodAsyncStateMachine has the same logic as MethodAsyncStateMachine above. The detail of the state machine will be discussed soon. Now it is clear that: async /await is a C# language level syntax sugar. There is no difference to await a async method or a normal method. As long as a method returns Task, it is awaitable. State machine and continuation To demonstrate more details in the state machine, a more complex method is created: internal class AsyncMethods { internal static async Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; } } In this method: There are multiple awaits. There are code before the awaits, and continuation code after each await After compilation, this multi-await method becomes the same as above single-await methods: internal class CompiledAsyncMethods { [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, Builder = AsyncTaskMethodBuilder<int>.Create(), State = -1 }; multiCallMethodAsyncStateMachine.Builder.Start(ref multiCallMethodAsyncStateMachine); return multiCallMethodAsyncStateMachine.Builder.Task; } } It creates and starts one single state machine, MultiCallMethodAsyncStateMachine: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { public int State; public AsyncTaskMethodBuilder<int> Builder; public int Arg0; public int Arg1; public int Arg2; public int Arg3; public int ResultOfAwait1; public int ResultOfAwait2; public int ResultToReturn; private TaskAwaiter<int> awaiter; void IAsyncStateMachine.MoveNext() { try { switch (this.State) { case -1: HelperMethods.Before(); this.awaiter = AsyncMethods.MethodAsync(this.Arg0, this.Arg1).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 0; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 0: this.ResultOfAwait1 = this.awaiter.GetResult(); HelperMethods.Continuation1(this.ResultOfAwait1); this.awaiter = AsyncMethods.MethodAsync(this.Arg2, this.Arg3).GetAwaiter(); if (!this.awaiter.IsCompleted) { this.State = 1; this.Builder.AwaitUnsafeOnCompleted(ref this.awaiter, ref this); } break; case 1: this.ResultOfAwait2 = this.awaiter.GetResult(); HelperMethods.Continuation2(this.ResultOfAwait2); this.ResultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; this.State = -2; this.Builder.SetResult(this.ResultToReturn); break; } } catch (Exception exception) { this.State = -2; this.Builder.SetException(exception); } } [DebuggerHidden] void IAsyncStateMachine.SetStateMachine(IAsyncStateMachine stateMachine) { this.Builder.SetStateMachine(stateMachine); } } Once again, the above state machine code is already refactored, but it still has a lot of things. More clean up can be done if we only keep the core logic, and the state machine can become very simple: [CompilerGenerated] [StructLayout(LayoutKind.Auto)] internal struct MultiCallMethodAsyncStateMachine : IAsyncStateMachine { // State: // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End public int State; public TaskCompletionSource<int> ResultToReturn; // int resultToReturn ... public int Arg0; // int Arg0 public int Arg1; // int arg1 public int Arg2; // int arg2 public int Arg3; // int arg3 public int ResultOfAwait1; // int resultOfAwait1 ... public int ResultOfAwait2; // int resultOfAwait2 ... private Task<int> currentTaskToAwait; /// <summary> /// Moves the state machine to its next state. /// </summary> public void MoveNext() // IAsyncStateMachine member. { try { switch (this.State) { // Original code is split by "await"s into "case"s: // case -1: // HelperMethods.Before(); // MethodAsync(Arg0, arg1); // case 0: // int resultOfAwait1 = await ... // HelperMethods.Continuation1(resultOfAwait1); // MethodAsync(arg2, arg3); // case 1: // int resultOfAwait2 = await ... // HelperMethods.Continuation2(resultOfAwait2); // int resultToReturn = resultOfAwait1 + resultOfAwait2; // return resultToReturn; case -1: // -1 is begin. HelperMethods.Before(); // Code before 1st await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg0, this.Arg1); // 1st task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 0. this.State = 0; MultiCallMethodAsyncStateMachine that1 = this; // Cannot use "this" in lambda so create a local variable. this.currentTaskToAwait.ContinueWith(_ => that1.MoveNext()); break; case 0: // Now 1st await is done. this.ResultOfAwait1 = this.currentTaskToAwait.Result; // Get 1st await's result. HelperMethods.Continuation1(this.ResultOfAwait1); // Code after 1st await and before 2nd await. this.currentTaskToAwait = AsyncMethods.MethodAsync(this.Arg2, this.Arg3); // 2nd task to await // When this.currentTaskToAwait is done, run this.MoveNext() and go to case 1. this.State = 1; MultiCallMethodAsyncStateMachine that2 = this; this.currentTaskToAwait.ContinueWith(_ => that2.MoveNext()); break; case 1: // Now 2nd await is done. this.ResultOfAwait2 = this.currentTaskToAwait.Result; // Get 2nd await's result. HelperMethods.Continuation2(this.ResultOfAwait2); // Code after 2nd await. int resultToReturn = this.ResultOfAwait1 + this.ResultOfAwait2; // Code after 2nd await. // End with resultToReturn. this.State = -2; // -2 is end. this.ResultToReturn.SetResult(resultToReturn); break; } } catch (Exception exception) { // End with exception. this.State = -2; // -2 is end. this.ResultToReturn.SetException(exception); } } /// <summary> /// Configures the state machine with a heap-allocated replica. /// </summary> /// <param name="stateMachine">The heap-allocated replica.</param> [DebuggerHidden] public void SetStateMachine(IAsyncStateMachine stateMachine) // IAsyncStateMachine member. { // No core logic. } } Only Task and TaskCompletionSource are involved in this version. And MultiCallMethodAsync() can be simplified to: [DebuggerStepThrough] [AsyncStateMachine(typeof(MultiCallMethodAsyncStateMachine))] // async internal static /*async*/ Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { MultiCallMethodAsyncStateMachine multiCallMethodAsyncStateMachine = new MultiCallMethodAsyncStateMachine() { Arg0 = arg0, Arg1 = arg1, Arg2 = arg2, Arg3 = arg3, ResultToReturn = new TaskCompletionSource<int>(), // -1: Begin // 0: 1st await is done // 1: 2nd await is done // ... // -2: End State = -1 }; multiCallMethodAsyncStateMachine.MoveNext(); // Original code are moved into this method. return multiCallMethodAsyncStateMachine.ResultToReturn.Task; } Now the whole state machine becomes very clean - it is about callback: Original code are split into pieces by “await”s, and each piece is put into each “case” in the state machine. Here the 2 awaits split the code into 3 pieces, so there are 3 “case”s. The “piece”s are chained by callback, that is done by Builder.AwaitUnsafeOnCompleted(callback), or currentTaskToAwait.ContinueWith(callback) in the simplified code. A previous “piece” will end with a Task (which is to be awaited), when the task is done, it will callback the next “piece”. The state machine’s state works with the “case”s to ensure the code “piece”s executes one after another. Callback If we focus on the point of callback, the simplification  can go even further – the entire state machine can be completely purged, and we can just keep the code inside MoveNext(). Now MultiCallMethodAsync() becomes: internal static Task<int> MultiCallMethodAsync(int arg0, int arg1, int arg2, int arg3) { TaskCompletionSource<int> taskCompletionSource = new TaskCompletionSource<int>(); try { // Oringinal code begins. HelperMethods.Before(); MethodAsync(arg0, arg1).ContinueWith(await1 => { int resultOfAwait1 = await1.Result; HelperMethods.Continuation1(resultOfAwait1); MethodAsync(arg2, arg3).ContinueWith(await2 => { int resultOfAwait2 = await2.Result; HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; // Oringinal code ends. taskCompletionSource.SetResult(resultToReturn); }); }); } catch (Exception exception) { taskCompletionSource.SetException(exception); } return taskCompletionSource.Task; } Please compare with the original async / await code: HelperMethods.Before(); int resultOfAwait1 = await MethodAsync(arg0, arg1); HelperMethods.Continuation1(resultOfAwait1); int resultOfAwait2 = await MethodAsync(arg2, arg3); HelperMethods.Continuation2(resultOfAwait2); int resultToReturn = resultOfAwait1 + resultOfAwait2; return resultToReturn; Yeah that is the magic of C# async / await: Await is not to wait. In a await expression, a Task object will be return immediately so that execution is not blocked. The continuation code is compiled as that Task’s callback code. When that task is done, continuation code will execute. Please notice that many details inside the state machine are omitted for simplicity, like context caring, etc. If you want to have a detailed picture, please do check out the source code of AsyncTaskMethodBuilder and TaskAwaiter.

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  • How can I get popup window using commandButton in Trinidad?

    - by vikram
    How can I get popup window using commandButton in Trinidad? My problem is that by clicking on Add button from dialogdemo.jspx, not any popup window or dialog box is opened. This is dialogdemo.jspx file: <jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" xmlns:f="http://java.sun.com/jsf/core" xmlns:tr="http://myfaces.apache.org/trinidad" version="1.2"> <jsp:directive.page contentType="text/html;charset=utf-8" /> <f:view> <tr:document title="Dialog Demo"> <tr:form> <!-- The field for the value; we point partialTriggers at the button to ensure it gets redrawn when we return --> <tr:inputText label="Pick a number:" partialTriggers="buttonId" value="#{launchDialog.input}" /> <!-- The button for launching the dialog: we've also configured the width and height of that window --> <tr:commandButton text="Add" action="dialog:chooseInteger" id="buttonId" windowWidth="300" windowHeight="200" partialSubmit="true" useWindow="true" returnListener="#{launchDialog.returned}" /> </tr:form> </tr:document> </f:view> </jsp:root> Here is the associated managed bean LaunchDialogBean.java: package jsfpkg; import org.apache.myfaces.trinidad.component.UIXInput; import org.apache.myfaces.trinidad.event.ReturnEvent; public class LaunchDialogBean { private UIXInput _input; public UIXInput getInput() { return _input; } public void setInput(UIXInput input) { _input = input; } public void returned(ReturnEvent event) { if (event.getReturnValue() != null) { getInput().setSubmittedValue(null); getInput().setValue(event.getReturnValue()); } } } Here is the popup file Popup.jspx: <jsp:root xmlns:jsp="http://java.sun.com/JSP/Page" xmlns:f="http://java.sun.com/jsf/core" xmlns:h="http://java.sun.com/jsf/html" xmlns:trh="http://myfaces.apache.org/trinidad/html" xmlns:tr="http://myfaces.apache.org/trinidad" version="2.0"> <jsp:directive.page contentType="text/html;charset=utf-8" /> <f:view> <tr:document title="Add dialog"> <tr:form> <!-- Two input fields --> <tr:panelForm> <tr:inputText label="Number 1:" value="#{chooseInteger.value1}" required="true" /> <tr:inputText label="Number 2:" value="#{chooseInteger.value2}" required="true" /> </tr:panelForm> <!-- Two buttons --> <tr:panelGroup layout="horizontal"> <tr:commandButton text="Submit" action="#{chooseInteger.select}" /> <tr:commandButton text="Cancel" immediate="true" action="#{chooseInteger.cancel}" /> </tr:panelGroup> </tr:form> </tr:document> </f:view> </jsp:root> For that I have written the bean ChooseIntegerBean.java package jsfpkg; import org.apache.myfaces.trinidad.context.RequestContext; public class ChooseIntegerBean { private Integer _value1; private Integer _value2; public Integer getValue1() { return _value1; } public void setValue1(Integer value1) { _value1 = value1; } public Integer getValue2() { return _value2; } public void setValue2(Integer value2) { _value2 = value2; } public String cancel() { RequestContext.getCurrentInstance().returnFromDialog(null, null); return null; } public String select() { Integer value = new Integer(getValue1().intValue() + getValue2().intValue()); RequestContext.getCurrentInstance().returnFromDialog(value, null); return null; } } Here is my faces-config.xml: <managed-bean> <managed-bean-name>chooseInteger</managed-bean-name> <managed-bean-class>jsfpkg.ChooseIntegerBean</managed-bean-class> <managed-bean-scope>request</managed-bean-scope> </managed-bean> <managed-bean> <managed-bean-name>launchDialog</managed-bean-name> <managed-bean-class>jsfpkg.LaunchDialogBean</managed-bean-class> <managed-bean-scope> request </managed-bean-scope> </managed-bean> <navigation-rule> <from-view-id>/dialogdemo.jspx</from-view-id> <navigation-case> <from-outcome>dialog:chooseInteger</from-outcome> <to-view-id>/dialogbox.jspx</to-view-id> </navigation-case> </navigation-rule>

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  • Signals and threads - good or bad design decision?

    - by Jens
    I have to write a program that performs highly computationally intensive calculations. The program might run for several days. The calculation can be separated easily in different threads without the need of shared data. I want a GUI or a web service that informs me of the current status. My current design uses BOOST::signals2 and BOOST::thread. It compiles and so far works as expected. If a thread finished one iteration and new data is available it calls a signal which is connected to a slot in the GUI class. My question(s): Is this combination of signals and threads a wise idea? I another forum somebody advised someone else not to "go down this road". Are there potential deadly pitfalls nearby that I failed to see? Is my expectation realistic that it will be "easy" to use my GUI class to provide a web interface or a QT, a VTK or a whatever window? Is there a more clever alternative (like other boost libs) that I overlooked? following code compiles with g++ -Wall -o main -lboost_thread-mt <filename>.cpp code follows: #include <boost/signals2.hpp> #include <boost/thread.hpp> #include <boost/bind.hpp> #include <iostream> #include <iterator> #include <string> using std::cout; using std::cerr; using std::string; /** * Called when a CalcThread finished a new bunch of data. */ boost::signals2::signal<void(string)> signal_new_data; /** * The whole data will be stored here. */ class DataCollector { typedef boost::mutex::scoped_lock scoped_lock; boost::mutex mutex; public: /** * Called by CalcThreads call the to store their data. */ void push(const string &s, const string &caller_name) { scoped_lock lock(mutex); _data.push_back(s); signal_new_data(caller_name); } /** * Output everything collected so far to std::out. */ void out() { typedef std::vector<string>::const_iterator iter; for (iter i = _data.begin(); i != _data.end(); ++i) cout << " " << *i << "\n"; } private: std::vector<string> _data; }; /** * Several of those can calculate stuff. * No data sharing needed. */ struct CalcThread { CalcThread(string name, DataCollector &datcol) : _name(name), _datcol(datcol) { } /** * Expensive algorithms will be implemented here. * @param num_results how many data sets are to be calculated by this thread. */ void operator()(int num_results) { for (int i = 1; i <= num_results; ++i) { std::stringstream s; s << "["; if (i == num_results) s << "LAST "; s << "DATA " << i << " from thread " << _name << "]"; _datcol.push(s.str(), _name); } } private: string _name; DataCollector &_datcol; }; /** * Maybe some VTK or QT or both will be used someday. */ class GuiClass { public: GuiClass(DataCollector &datcol) : _datcol(datcol) { } /** * If the GUI wants to present or at least count the data collected so far. * @param caller_name is the name of the thread whose data is new. */ void slot_data_changed(string caller_name) const { cout << "GuiClass knows: new data from " << caller_name << std::endl; } private: DataCollector & _datcol; }; int main() { DataCollector datcol; GuiClass mc(datcol); signal_new_data.connect(boost::bind(&GuiClass::slot_data_changed, &mc, _1)); CalcThread r1("A", datcol), r2("B", datcol), r3("C", datcol), r4("D", datcol), r5("E", datcol); boost::thread t1(r1, 3); boost::thread t2(r2, 1); boost::thread t3(r3, 2); boost::thread t4(r4, 2); boost::thread t5(r5, 3); t1.join(); t2.join(); t3.join(); t4.join(); t5.join(); datcol.out(); cout << "\nDone" << std::endl; return 0; }

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