datacontext - Page 18 - Developer IT

Foreach loop problem for Iqueyable object

- by Vikas

Hi, Can we use foreach loop for Iqueryable object? I'd like to do something as follow: query = Iqueryable<Myclass> = objDataContext.Myclass; // objDataContext is an object of LINQ datacontext class int[] arr1 = new int[] { 3, 4, 5 }; foreach (int i in arr1) { query = query.Where(q => (q.f_id1 == i || q.f_id2 == i || q.f_id3 == i)); } It gives me wrong output as each time value if i is changed.

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How to bind a property defined as usercontrol in XAML?

- by EricSch

In XAML (Root is a UserControl), I have defined a grid with two columns. In a ViewModel layer, I have defined a property as UserControl. The ViewModel is set as DataContext of the XAML. How I can bind this property of type UserControl declarative to the grid? Thanks

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wpf how to bind a listbox to a list (two ways) - c#

- by user429400

Hi, I want to create a 2 way bind between a listbox and a .NET list. In my GUI, I have a listbox, a textbox and add and remove buttons. The listbox displays cars, and my goal is to create a 2way bind between the .Net car list and the listbox: when the user enters a car into the textbox, it gets updated only in the .Net list, and the listbox is updated automatically. When the user press the GUI "remove" button, a car gets removed from the GUI and the .Net list is updated automatically. I've started to write the xaml code, but figured that I don't actually know how to do the binding on both sides (c# and xaml): <Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:c="clr-namespace:WpfApplication1" Title="Window1" Height="300" Width="369" Loaded="Window_Loaded"> <Window.Resources> <ObjectDataProvider x:Key="carsData" ObjectType="{x:Type c:Window1}" /> </Window.Resources> <Grid Width="332"> <ListBox Margin="10,62,0,100" Name="myListBox" HorizontalAlignment="Left" Width="120" ItemsSource="{Binding Source={StaticResource CarsData}}"/> <Button Height="23" Margin="66,0,0,65" Name="addBtn" VerticalAlignment="Bottom" Click="addBtn_Click" HorizontalAlignment="Left" Width="64">add</Button> <TextBox Margin="10,0,0,64.48" Name="myTextBox" Height="23" VerticalAlignment="Bottom" HorizontalAlignment="Left" Width="47" /> <Button Height="23" Margin="66,0,0,33" Name="removeButton" VerticalAlignment="Bottom" HorizontalAlignment="Left" Width="64" Click="removeButton_Click">Remove</Button> </Grid> </Window> There is my c# code: namespace WpfApplication1 { public partial class Window1 : Window { MyModel listMgr; ObservableCollection carList; public Window1() { InitializeComponent(); listMgr = new MyModel(); } private void addBtn_Click(object sender, RoutedEventArgs e) { listMgr.add(new Car(0, myTextBox.Text, 2011)); } private void removeButton_Click(object sender, RoutedEventArgs e) { //myListBox.Items.RemoveAt(0); } private void Window_Loaded(object sender, RoutedEventArgs e) { carList = listMgr.getList(); myListBox.DataContext = carList; //secondListBox.DataContext = carList; } } } Thanks, Li

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Translate LINQ to sql statement

- by zielu1

Hi, I want to translate LINQ expression tree to SQL statement and I don't want to write my own code for this. Example: var query = from c in Customers where c.Country == "UK" && c.City == "London" select c); To SELECT ... FROM Customers AS c WHERE c.Country = "UK" AND c.City = "London" I know DataContext.Log, but I want to use: query.ToSqlStatementString() Thanks

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Validation in Silverlight

- by Timmy Kokke

Getting started with the basics Validation in Silverlight can get very complex pretty easy. The DataGrid control is the only control that does data validation automatically, but often you want to validate your own entry form. Values a user may enter in this form can be restricted by the customer and have to fit an exact fit to a list of requirements or you just want to prevent problems when saving the data to the database. Showing a message to the user when a value is entered is pretty straight forward as I’ll show you in the following example. This (default) Silverlight textbox is data-bound to a simple data class. It has to be bound in “Two-way” mode to be sure the source value is updated when the target value changes. The INotifyPropertyChanged interface must be implemented by the data class to get the notification system to work. When the property changes a simple check is performed and when it doesn’t match some criteria an ValidationException is thrown. The ValidatesOnExceptions binding attribute is set to True to tell the textbox it should handle the thrown ValidationException. Let’s have a look at some code now. The xaml should contain something like below. The most important part is inside the binding. In this case the Text property is bound to the “Name” property in TwoWay mode. It is also told to validate on exceptions. This property is false by default. <StackPanel Orientation="Horizontal"> <TextBox Width="150" x:Name="Name" Text="{Binding Path=Name, Mode=TwoWay, ValidatesOnExceptions=True}"/> <TextBlock Text="Name"/> </StackPanel> The data class in this first example is a very simplified person class with only one property: string Name. The INotifyPropertyChanged interface is implemented and the PropertyChanged event is fired when the Name property changes. When the property changes a check is performed to see if the new string is null or empty. If this is the case a ValidationException is thrown explaining that the entered value is invalid. public class PersonData:INotifyPropertyChanged { private string _name; public string Name { get { return _name; } set { if (_name != value) { if(string.IsNullOrEmpty(value)) throw new ValidationException("Name is required"); _name = value; if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Name")); } } } public event PropertyChangedEventHandler PropertyChanged=delegate { }; } The last thing that has to be done is letting binding an instance of the PersonData class to the DataContext of the control. This is done in the code behind file. public partial class Demo1 : UserControl { public Demo1() { InitializeComponent(); this.DataContext = new PersonData() {Name = "Johnny Walker"}; } } Error Summary In many cases you would have more than one entry control. A summary of errors would be nice in such case. With a few changes to the xaml an error summary, like below, can be added. First, add a namespace to the xaml so the control can be used. Add the following line to the header of the .xaml file. xmlns:Controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.Input" Next, add the control to the layout. To get the result as in the image showed earlier, add the control right above the StackPanel from the first example. It’s got a small margin to separate it from the textbox a little. <Controls:ValidationSummary Margin="8"/> The ValidationSummary control has to be notified that an ValidationException occurred. This can be done with a small change to the xaml too. Add the NotifyOnValidationError to the binding expression. By default this value is set to false, so nothing would be notified. Set the property to true to get it to work. <TextBox Width="150" x:Name="Name" Text="{Binding Name, Mode=TwoWay, ValidatesOnExceptions=True, NotifyOnValidationError=True}"/> Data annotation Validating data in the setter is one option, but not my personal favorite. It’s the easiest way if you have a single required value you want to check, but often you want to validate more. Besides, I don’t consider it best practice to write logic in setters. The way used by frameworks like WCF Ria Services is the use of attributes on the properties. Instead of throwing exceptions you have to call the static method ValidateProperty on the Validator class. This call stays always the same for a particular property, not even when you change the attributes on the property. To mark a property “Required” you can use the RequiredAttribute. This is what the Name property is going to look like: [Required] public string Name { get { return _name; } set { if (_name != value) { Validator.ValidateProperty(value, new ValidationContext(this, null, null){ MemberName = "Name" }); _name = value; if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Name")); } } } The ValidateProperty method takes the new value for the property and an instance of ValidationContext. The properties passed to the constructor of the ValidationContextclass are very straight forward. This part is the same every time. The only thing that changes is the MemberName property of the ValidationContext. Property has to hold the name of the property you want to validate. It’s the same value you provide the PropertyChangedEventArgs with. The System.ComponentModel.DataAnnotation contains eight different validation attributes including a base class to create your own. They are: RequiredAttribute Specifies that a value must be provided. RangeAttribute The provide value must fall in the specified range. RegularExpressionAttribute Validates is the value matches the regular expression. StringLengthAttribute Checks if the number of characters in a string falls between a minimum and maximum amount. CustomValidationAttribute Use a custom method to validate the value. DataTypeAttribute Specify a data type using an enum or a custom data type. EnumDataTypeAttribute Makes sure the value is found in a enum. ValidationAttribute A base class for custom validation attributes All of these will ensure that an validation exception is thrown, except the DataTypeAttribute. This attribute is used to provide some additional information about the property. You can use this information in your own code. [Required] [Range(0,125,ErrorMessage = "Value is not a valid age")] public int Age { It’s no problem to stack different validation attributes together. For example, when an Age is required and must fall in the range from 0 to 125: [Required, StringLength(255,MinimumLength = 3)] public string Name { Or in one row like this, for a required Name with at least 3 characters and a maximum of 255: Delayed validation Having properties marked as required can be very useful. The only downside to the technique described earlier is that you have to change the value in order to get it validated. What if you start out with empty an empty entry form? All fields are empty and thus won’t be validated. With this small trick you can validate at the moment the user click the submit button. <TextBox Width="150" x:Name="NameField" Text="{Binding Name, Mode=TwoWay, ValidatesOnExceptions=True, NotifyOnValidationError=True, UpdateSourceTrigger=Explicit}"/> By default, when a TwoWay bound control looses focus the value is updated. When you added validation like I’ve shown you earlier, the value is validated. To overcome this, you have to tell the binding update explicitly by setting the UpdateSourceTrigger binding property to Explicit: private void SubmitButtonClick(object sender, RoutedEventArgs e) { NameField.GetBindingExpression(TextBox.TextProperty).UpdateSource(); } This way, the binding is in two direction but the source is only updated, thus validated, when you tell it to. In the code behind you have to call the UpdateSource method on the binding expression, which you can get from the TextBox. Conclusion Data validation is something you’ll probably want on almost every entry form. I always thought it was hard to do, but it wasn’t. If you can throw an exception you can do validation. If you want to know anything more in depth about something I talked about in this article let me know. I might write an entire post to that.

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Adding Volcanos and Options - Earthquake Locator, part 2

- by Bobby Diaz

Since volcanos are often associated with earthquakes, and vice versa, I decided to show recent volcanic activity on the Earthquake Locator map. I am pulling the data from a website created for a joint project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program, found here. They provide a Weekly Volcanic Activity Report as an RSS feed. I started implementing this new functionality by creating a new Volcano entity in the domain model and adding the following to the EarthquakeService class (I also factored out the common reading/parsing helper methods to a separate FeedReader class that can be used by multiple domain service classes): private static readonly string VolcanoFeedUrl = ConfigurationManager.AppSettings["VolcanoFeedUrl"]; /// <summary> /// Gets the volcano data for the previous week. /// </summary> /// <returns>A queryable collection of <see cref="Volcano"/> objects.</returns> public IQueryable<Volcano> GetVolcanos() { var feed = FeedReader.Load(VolcanoFeedUrl); var list = new List<Volcano>(); if ( feed != null ) { foreach ( var item in feed.Items ) { var quake = CreateVolcano(item); if ( quake != null ) { list.Add(quake); } } } return list.AsQueryable(); } /// <summary> /// Creates a <see cref="Volcano"/> object for each item in the RSS feed. /// </summary> /// <param name="item">The RSS item.</param> /// <returns></returns> private Volcano CreateVolcano(SyndicationItem item) { Volcano volcano = null; string title = item.Title.Text; string desc = item.Summary.Text; double? latitude = null; double? longitude = null; FeedReader.GetGeoRssPoint(item, out latitude, out longitude); if ( !String.IsNullOrEmpty(title) ) { title = title.Substring(0, title.IndexOf('-')); } if ( !String.IsNullOrEmpty(desc) ) { desc = String.Join("\n\n", desc .Replace("<p>", "") .Split( new string[] { "</p>" }, StringSplitOptions.RemoveEmptyEntries) .Select(s => s.Trim()) .ToArray()) .Trim(); } if ( latitude != null && longitude != null ) { volcano = new Volcano() { Id = item.Id, Title = title, Description = desc, Url = item.Links.Select(l => l.Uri.OriginalString).FirstOrDefault(), Latitude = latitude.GetValueOrDefault(), Longitude = longitude.GetValueOrDefault() }; } return volcano; } I then added the corresponding LoadVolcanos() method and Volcanos collection to the EarthquakeViewModel class in much the same way I did with the Earthquakes in my previous article in this series. Now that I am starting to add more information to the map, I wanted to give the user some options as to what is displayed and allowing them to choose what gets turned off. I have updated the MainPage.xaml to look like this: <UserControl x:Class="EarthquakeLocator.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:basic="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls" xmlns:bing="clr-namespace:Microsoft.Maps.MapControl;assembly=Microsoft.Maps.MapControl" xmlns:vm="clr-namespace:EarthquakeLocator.ViewModel" mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480" > <UserControl.Resources> <DataTemplate x:Key="EarthquakeTemplate"> <Ellipse Fill="Red" Stroke="Black" StrokeThickness="1" Width="{Binding Size}" Height="{Binding Size}" bing:MapLayer.Position="{Binding Location}" bing:MapLayer.PositionOrigin="Center"> <ToolTipService.ToolTip> <StackPanel> <TextBlock Text="{Binding Title}" FontSize="14" FontWeight="Bold" /> <TextBlock Text="{Binding UtcTime}" /> <TextBlock Text="{Binding LocalTime}" /> <TextBlock Text="{Binding DepthDesc}" /> </StackPanel> </ToolTipService.ToolTip> </Ellipse> </DataTemplate> <DataTemplate x:Key="VolcanoTemplate"> <Polygon Fill="Gold" Stroke="Black" StrokeThickness="1" Points="0,10 5,0 10,10" bing:MapLayer.Position="{Binding Location}" bing:MapLayer.PositionOrigin="Center" MouseLeftButtonUp="Volcano_MouseLeftButtonUp"> <ToolTipService.ToolTip> <StackPanel> <TextBlock Text="{Binding Title}" FontSize="14" FontWeight="Bold" /> <TextBlock Text="Click icon for more information..." /> </StackPanel> </ToolTipService.ToolTip> </Polygon> </DataTemplate> </UserControl.Resources> <UserControl.DataContext> <vm:EarthquakeViewModel AutoLoadData="True" /> </UserControl.DataContext> <Grid x:Name="LayoutRoot"> <bing:Map x:Name="map" CredentialsProvider="--Your-Bing-Maps-Key--" Center="{Binding MapCenter, Mode=TwoWay}" ZoomLevel="{Binding ZoomLevel, Mode=TwoWay}"> <bing:MapItemsControl ItemsSource="{Binding Earthquakes}" ItemTemplate="{StaticResource EarthquakeTemplate}" /> <bing:MapItemsControl ItemsSource="{Binding Volcanos}" ItemTemplate="{StaticResource VolcanoTemplate}" /> </bing:Map> <basic:TabControl x:Name="tabs" VerticalAlignment="Bottom" MaxHeight="25" Opacity="0.7"> <basic:TabItem Margin="90,0,-90,0" MouseLeftButtonUp="TabItem_MouseLeftButtonUp"> <basic:TabItem.Header> <TextBlock x:Name="txtHeader" Text="Options" FontSize="13" FontWeight="Bold" /> </basic:TabItem.Header> <StackPanel Orientation="Horizontal"> <TextBlock Text="Earthquakes:" FontWeight="Bold" Margin="3" /> <StackPanel Margin="3"> <CheckBox Content=" < 4.0" IsChecked="{Binding ShowLt4, Mode=TwoWay}" /> <CheckBox Content="4.0 - 4.9" IsChecked="{Binding Show4s, Mode=TwoWay}" /> <CheckBox Content="5.0 - 5.9" IsChecked="{Binding Show5s, Mode=TwoWay}" /> </StackPanel> <StackPanel Margin="10,3,3,3"> <CheckBox Content="6.0 - 6.9" IsChecked="{Binding Show6s, Mode=TwoWay}" /> <CheckBox Content="7.0 - 7.9" IsChecked="{Binding Show7s, Mode=TwoWay}" /> <CheckBox Content="8.0 +" IsChecked="{Binding ShowGe8, Mode=TwoWay}" /> </StackPanel> <TextBlock Text="Other:" FontWeight="Bold" Margin="50,3,3,3" /> <StackPanel Margin="3"> <CheckBox Content="Volcanos" IsChecked="{Binding ShowVolcanos, Mode=TwoWay}" /> </StackPanel> </StackPanel> </basic:TabItem> </basic:TabControl> </Grid> </UserControl> Notice that I added a VolcanoTemplate that uses a triangle-shaped Polygon to represent the Volcano locations, and I also added a second <bing:MapItemsControl /> tag to the map to bind to the Volcanos collection. The TabControl found below the map houses the options panel that will present the user with several checkboxes so they can filter the different points based on type and other properties (i.e. Magnitude). Initially, the TabItem is collapsed to reduce it's footprint, but the screen shot below shows the options panel expanded to reveal the available settings: I have updated the Source Code and Live Demo to include these new features. Happy Mapping!

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Parallel LINQ - PLINQ

- by nmarun

Turns out now with .net 4.0 we can run a query like a multi-threaded application. Say you want to query a collection of objects and return only those that meet certain conditions. Until now, we basically had one ‘control’ that iterated over all the objects in the collection, checked the condition on each object and returned if it passed. We obviously agree that if we can ‘break’ this task into smaller ones, assign each task to a different ‘control’ and ask all the controls to do their job - in-parallel, the time taken the finish the entire task will be much lower. Welcome to PLINQ. Let’s take some examples. I have the following method that uses our good ol’ LINQ. 1: private static void Linq(int lowerLimit, int upperLimit) 2: { 3: // populate an array with int values from lowerLimit to the upperLimit 4: var source = Enumerable.Range(lowerLimit, upperLimit); 5: 6: // Start a timer 7: Stopwatch stopwatch = new Stopwatch(); 8: stopwatch.Start(); 9: 10: // set the expectation => build the expression tree 11: var evenNumbers = from num in source 12: where IsDivisibleBy(num, 2) 13: select num; 14: 15: // iterate over and print the returned items 16: foreach (var number in evenNumbers) 17: { 18: Console.WriteLine(string.Format("** {0}", number)); 19: } 20: 21: stopwatch.Stop(); 22: 23: // check the metrics 24: Console.WriteLine(String.Format("Elapsed {0}ms", stopwatch.ElapsedMilliseconds)); 25: } I’ve added comments for the major steps, but the only thing I want to talk about here is the IsDivisibleBy() method. I know I could have just included the logic directly in the where clause. I called a method to add ‘delay’ to the execution of the query - to simulate a loooooooooong operation (will be easier to compare the results). 1: private static bool IsDivisibleBy(int number, int divisor) 2: { 3: // iterate over some database query 4: // to add time to the execution of this method; 5: // the TableB has around 10 records 6: for (int i = 0; i < 10; i++) 7: { 8: DataClasses1DataContext dataContext = new DataClasses1DataContext(); 9: var query = from b in dataContext.TableBs select b; 10: 11: foreach (var row in query) 12: { 13: // Do NOTHING (wish my job was like this) 14: } 15: } 16: 17: return number % divisor == 0; 18: } Now, let’s look at how to modify this to PLINQ. 1: private static void Plinq(int lowerLimit, int upperLimit) 2: { 3: // populate an array with int values from lowerLimit to the upperLimit 4: var source = Enumerable.Range(lowerLimit, upperLimit); 5: 6: // Start a timer 7: Stopwatch stopwatch = new Stopwatch(); 8: stopwatch.Start(); 9: 10: // set the expectation => build the expression tree 11: var evenNumbers = from num in source.AsParallel() 12: where IsDivisibleBy(num, 2) 13: select num; 14: 15: // iterate over and print the returned items 16: foreach (var number in evenNumbers) 17: { 18: Console.WriteLine(string.Format("** {0}", number)); 19: } 20: 21: stopwatch.Stop(); 22: 23: // check the metrics 24: Console.WriteLine(String.Format("Elapsed {0}ms", stopwatch.ElapsedMilliseconds)); 25: } That’s it, this is now in PLINQ format. Oh and if you haven’t found the difference, look line 11 a little more closely. You’ll see an extension method ‘AsParallel()’ added to the ‘source’ variable. Couldn’t be more simpler right? So this is going to improve the performance for us. Let’s test it. So in my Main method of the Console application that I’m working on, I make a call to both. 1: static void Main(string[] args) 2: { 3: // set lower and upper limits 4: int lowerLimit = 1; 5: int upperLimit = 20; 6: // call the methods 7: Console.WriteLine("Calling Linq() method"); 8: Linq(lowerLimit, upperLimit); 9: 10: Console.WriteLine(); 11: Console.WriteLine("Calling Plinq() method"); 12: Plinq(lowerLimit, upperLimit); 13: 14: Console.ReadLine(); // just so I get enough time to read the output 15: } YMMV, but here are the results that I got: It’s quite obvious from the above results that the Plinq() method is taking considerably less time than the Linq() version. I’m sure you’ve already noticed that the output of the Plinq() method is not in order. That’s because, each of the ‘control’s we sent to fetch the results, reported with values as and when they obtained them. This is something about parallel LINQ that one needs to remember – the collection cannot be guaranteed to be undisturbed. This could be counted as a negative about PLINQ (emphasize ‘could’). Nevertheless, if we want the collection to be sorted, we can use a SortedSet (.net 4.0) or build our own custom ‘sorter’. Either way we go, there’s a good chance we’ll end up with a better performance using PLINQ. And there’s another negative of PLINQ (depending on how you see it). This is regarding the CPU cycles. See the usage for Linq() method (used ResourceMonitor): I have dual CPU’s and see the height of the peak in the bottom two blocks and now compare to what happens when I run the Plinq() method. The difference is obvious. Higher usage, but for a shorter duration (width of the peak). Both these points make sense in both cases. Linq() runs for a longer time, but uses less resources whereas Plinq() runs for a shorter time and consumes more resources. Even after knowing all these, I’m still inclined towards PLINQ. PLINQ rocks! (no hard feelings LINQ)

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Implementing a generic repository for WCF data services

- by cibrax

The repository implementation I am going to discuss here is not exactly what someone would call repository in terms of DDD, but it is an abstraction layer that becomes handy at the moment of unit testing the code around this repository. In other words, you can easily create a mock to replace the real repository implementation. The WCF Data Services update for .NET 3.5 introduced a nice feature to support two way data bindings, which is very helpful for developing WPF or Silverlight based application but also for implementing the repository I am going to talk about. As part of this feature, the WCF Data Services Client library introduced a new collection DataServiceCollection<T> that implements INotifyPropertyChanged to notify the data context (DataServiceContext) about any change in the association links. This means that it is not longer necessary to manually set or remove the links in the data context when an item is added or removed from a collection. Before having this new collection, you basically used the following code to add a new item to a collection. Order order = new Order { Name = "Foo" }; OrderItem item = new OrderItem { Name = "bar", UnitPrice = 10, Qty = 1 }; var context = new OrderContext(); context.AddToOrders(order); context.AddToOrderItems(item); context.SetLink(item, "Order", order); context.SaveChanges(); Now, thanks to this new collection, everything is much simpler and similar to what you have in other ORMs like Entity Framework or L2S. Order order = new Order { Name = "Foo" }; OrderItem item = new OrderItem { Name = "bar", UnitPrice = 10, Qty = 1 }; order.Items.Add(item); var context = new OrderContext(); context.AddToOrders(order); context.SaveChanges(); In order to use this new feature, you first need to enable V2 in the data service, and then use some specific arguments in the datasvcutil tool (You can find more information about this new feature and how to use it in this post). DataSvcUtil /uri:"http://localhost:3655/MyDataService.svc/" /out:Reference.cs /dataservicecollection /version:2.0 Once you use those two arguments, the generated proxy classes will use DataServiceCollection<T> rather than a simple ObjectCollection<T>, which was the default collection in V1. There are some aspects that you need to know to use this feature correctly. 1. All the entities retrieved directly from the data context with a query track the changes and report those to the data context automatically. 2. A entity created with “new” does not track any change in the properties or associations. In order to enable change tracking in this entity, you need to do the following trick. public Order CreateOrder() { var collection = new DataServiceCollection<Order>(this.context); var order = new Order(); collection.Add(order); return order; } You basically need to create a collection, and add the entity to that collection with the “Add” method to enable change tracking on that entity. 3. If you need to attach an existing entity (For example, if you created the entity with the “new” operator rather than retrieving it from the data context with a query) to a data context for tracking changes, you can use the “Load” method in the DataServiceCollection. var order = new Order { Id = 1 }; var collection = new DataServiceCollection<Order>(this.context); collection.Load(order); In this case, the order with Id = 1 must exist on the data source exposed by the Data service. Otherwise, you will get an error because the entity did not exist. These cool extensions methods discussed by Stuart Leeks in this post to replace all the magic strings in the “Expand” operation with Expression Trees represent another feature I am going to use to implement this generic repository. Thanks to these extension methods, you could replace the following query with magic strings by a piece of code that only uses expressions. Magic strings, var customers = dataContext.Customers .Expand("Orders") .Expand("Orders/Items") Expressions, var customers = dataContext.Customers .Expand(c => c.Orders.SubExpand(o => o.Items)) That query basically returns all the customers with their orders and order items. Ok, now that we have the automatic change tracking support and the expression support for explicitly loading entity associations, we are ready to create the repository. The interface for this repository looks like this,public interface IRepository { T Create<T>() where T : new(); void Update<T>(T entity); void Delete<T>(T entity); IQueryable<T> RetrieveAll<T>(params Expression<Func<T, object>>[] eagerProperties); IQueryable<T> Retrieve<T>(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] eagerProperties); void Attach<T>(T entity); void SaveChanges(); } The Retrieve and RetrieveAll methods are used to execute queries against the data service context. While both methods receive an array of expressions to load associations explicitly, only the Retrieve method receives a predicate representing the “where” clause. The following code represents the final implementation of this repository.public class DataServiceRepository: IRepository { ResourceRepositoryContext context; public DataServiceRepository() : this (new DataServiceContext()) { } public DataServiceRepository(DataServiceContext context) { this.context = context; } private static string ResolveEntitySet(Type type) { var entitySetAttribute = (EntitySetAttribute)type.GetCustomAttributes(typeof(EntitySetAttribute), true).FirstOrDefault(); if (entitySetAttribute != null) return entitySetAttribute.EntitySet; return null; } public T Create<T>() where T : new() { var collection = new DataServiceCollection<T>(this.context); var entity = new T(); collection.Add(entity); return entity; } public void Update<T>(T entity) { this.context.UpdateObject(entity); } public void Delete<T>(T entity) { this.context.DeleteObject(entity); } public void Attach<T>(T entity) { var collection = new DataServiceCollection<T>(this.context); collection.Load(entity); } public IQueryable<T> Retrieve<T>(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] eagerProperties) { var entitySet = ResolveEntitySet(typeof(T)); var query = context.CreateQuery<T>(entitySet); foreach (var e in eagerProperties) { query = query.Expand(e); } return query.Where(predicate); } public IQueryable<T> RetrieveAll<T>(params Expression<Func<T, object>>[] eagerProperties) { var entitySet = ResolveEntitySet(typeof(T)); var query = context.CreateQuery<T>(entitySet); foreach (var e in eagerProperties) { query = query.Expand(e); } return query; } public void SaveChanges() { this.context.SaveChanges(SaveChangesOptions.Batch); } } For instance, you can use the following code to retrieve customers with First name equal to “John”, and all their orders in a single call. repository.Retrieve<Customer>( c => c.FirstName == “John”, //Where c => c.Orders.SubExpand(o => o.Items)); In case, you want to have some pre-defined queries that you are going to use across several places, you can put them in an specific class. public static class CustomerQueries { public static Expression<Func<Customer, bool>> LastNameEqualsTo(string lastName) { return c => c.LastName == lastName; } } And then, use it with the repository. repository.Retrieve<Customer>( CustomerQueries.LastNameEqualsTo("foo"), c => c.Orders.SubExpand(o => o.Items));

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Connect ViewModel and View using Unity

- by brainbox

In this post i want to describe the approach of connecting View and ViewModel which I'm using in my last project.The main idea is to do it during resolve inside of unity container. It can be achived using InjectionFactory introduced in Unity 2.0 public static class MVVMUnityExtensions{ public static void RegisterView<TView, TViewModel>(this IUnityContainer container) where TView : FrameworkElement { container.RegisterView<TView, TView, TViewModel>(); } public static void RegisterView<TViewFrom, TViewTo, TViewModel>(this IUnityContainer container) where TViewTo : FrameworkElement, TViewFrom { container.RegisterType<TViewFrom>(new InjectionFactory( c => { var model = c.Resolve<TViewModel>(); var view = Activator.CreateInstance<TViewTo>(); view.DataContext = model; return view; } )); }}}And here is the sample how it could be used:var unityContainer = new UnityContainer();unityContainer.RegisterView<IFooView, FooView, FooViewModel>();IFooView view = unityContainer.Resolve<IFooView>(); // view with injected viewmodel in its datacontextPlease tell me your prefered way to connect viewmodel and view.

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Designing a Database Application with OOP

- by Tim C

I often develop SQL database applications using Linq, and my methodology is to build model classes to represent each table, and each table that needs inserting or updating gets a Save() method (which either does an InsertOnSubmit() or SubmitChanges(), depending on the state of the object). Often, when I need to represent a collection of records, I'll create a class that inherits from a List-like object of the atomic class. ex. public class CustomerCollection : CoreCollection<Customer> { } Recently, I was working on an application where end-users were experiencing slowness, where each of the objects needed to be saved to the database if they met a certain criteria. My Save() method was slow, presumably because I was making all kinds of round-trips to the server, and calling DataContext.SubmitChanges() after each atomic save. So, the code might have looked something like this foreach(Customer c in customerCollection) { if(c.ShouldSave()) { c.Save(); } } I worked through multiple strategies to optimize, but ultimately settled on passing a big string of data to a SQL stored procedure, where the string has all the data that represents the records I was working with - it might look something like this: CustomerID:34567;CurrentAddress:23 3rd St;CustomerID:23456;CurrentAddress:123 4th St So, SQL server parses the string, performs the logic to determine appropriateness of save, and then Inserts, Updates, or Ignores. With C#/Linq doing this work, it saved 5-10 records / s. When SQL does it, I get 100 records / s, so there is no denying the Stored Proc is more efficient; however, I hate the solution because it doesn't seem nearly as clean or safe. My real concern is that I don't have any better solutions that hold a candle to the performance of the stored proc solution. Am I doing something obviously wrong in how I'm thinking about designing database applications? Are there better ways of designing database applications?

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Generic Repository with SQLite and SQL Compact Databases

- by Andrew Petersen

I am creating a project that has a mobile app (Xamarin.Android) using a SQLite database and a WPF application (Code First Entity Framework 5) using a SQL Compact database. This project will even eventually have a SQL Server database as well. Because of this I am trying to create a generic repository, so that I can pass in the correct context depending on which application is making the request. The issue I ran into is my DataContext for the SQL Compact database inherits from DbContext and the SQLite database inherits from SQLiteConnection. What is the best way to make this generic, so that it doesn't matter what kind of database is on the back end? This is what I have tried so far on the SQL Compact side: public interface IRepository<TEntity> { TEntity Add(TEntity entity); } public class Repository<TEntity, TContext> : IRepository<TEntity>, IDisposable where TEntity : class where TContext : DbContext { private readonly TContext _context; public Repository(DbContext dbContext) { _context = dbContext as TContext; } public virtual TEntity Add(TEntity entity) { return _context.Set<TEntity>().Add(entity); } } And on the SQLite side: public class ElverDatabase : SQLiteConnection { static readonly object Locker = new object(); public ElverDatabase(string path) : base(path) { CreateTable<Ticket>(); } public int Add<T>(T item) where T : IBusinessEntity { lock (Locker) { return Insert(item); } } }

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How can I bind a custom color to WPF toolkit ColorPicker? [on hold]

- by tube-builder

I need to bind the SelectedColor property of ColorPicker to a custom color which is not present in available colors. I created a simple test to show my problem. My xaml: <xctk:ColorPicker SelectedColor="{Binding Path=Test}"></xctk:ColorPicker> Code behind (CurrentStyle.PenColor returns an integer value which equals 13109765): public Color Test { get; set; } public MyClass() { DataContext = this; Test = Color.FromArgb((byte)((CurrentStyle.PenColor >> 24) & 0xFF), (byte)((CurrentStyle.PenColor >> 16) & 0xFF), (byte)((CurrentStyle.PenColor >> 8) & 0xFF), (byte)(CurrentStyle.PenColor & 0xFF)); InitializeComponent(); } And that's how my ColorPicker looks like when the window is loaded (I don't have enough rep to post images so it's just links): http://s22.postimg.org/frzh2fgy9/image.png Though, when I go to Advanced colors I can see that the color has been recognized and set correctly. Here is a pic: http://s13.postimg.org/gjv4cmy07/image.png Hope for your help. Thanks a lot! EDIT I implemented INotifyPropertyChanged, still to no avail. Here's the code: public Color Test { get { return test; } set { if (test != value) { test = value; OnPropertyChanged("Test"); } } } public event PropertyChangedEventHandler PropertyChanged; protected void OnPropertyChanged(string prop) { if (this.PropertyChanged != null) this.PropertyChanged(this, new PropertyChangedEventArgs(prop)); } Maybe I'm doing smth wrong here.

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Adventures in Windows 8: Placing items in a GridView with a ColumnSpan or RowSpan

- by Laurent Bugnion

Currently working on a Windows 8 app for an important client, I will be writing about small issues, tips and tricks, ideas and whatever occurs to me during the development and the integration of this app. When working with a GridView, it is quite common to use a VariableSizedWrapGrid as the ItemsPanel. This creates a nice flowing layout which will auto-adapt for various resolutions. This is ideal when you want to build views like the Windows 8 start menu. However immediately we notice that the Start menu allows to place items on one column (Smaller) or two columns (Larger). This switch happens through the AppBar. So how do we implement that in our app? Using ColumnSpan and RowSpan When you use a VariableSizedWrapGrid directly in your XAML, you can attach the VariableSizedWrapGrid.ColumnSpan and VariableSizedWrapGrid.RowSpan attached properties directly to an item to create the desired effect. For instance this code create this output (shown in Blend but it runs just the same): <VariableSizedWrapGrid ItemHeight="100" ItemWidth="100" Width="200" Orientation="Horizontal"> <Rectangle Fill="Purple" /> <Rectangle Fill="Orange" /> <Rectangle Fill="Yellow" VariableSizedWrapGrid.ColumnSpan="2" /> <Rectangle Fill="Red" VariableSizedWrapGrid.ColumnSpan="2" VariableSizedWrapGrid.RowSpan="2" /> <Rectangle Fill="Green" VariableSizedWrapGrid.RowSpan="2" /> <Rectangle Fill="Blue" /> <Rectangle Fill="LightGray" /> </VariableSizedWrapGrid> Using the VariableSizedWrapGrid as ItemsPanel When you use a GridView however, you typically bind the ItemsSource property to a collection, for example in a viewmodel. In that case, you want to be able to switch the ColumnSpan and RowSpan depending on properties on the item. I tried to find a way to bind the VariableSizedWrapGrid.ColumnSpan attached property on the GridView’s ItemContainerStyle template to an observable property on the item, but it didn’t work. Instead, I decided to use a StyleSelector to switch the GridViewItem’s style. Here’s how: First I added my two GridViews to my XAML as follows: <Page.Resources> <local:MainViewModel x:Key="Main" /> <DataTemplate x:Key="DataTemplate1"> <Grid Background="{Binding Brush}"> <TextBlock Text="{Binding BrushCode}" /> </Grid> </DataTemplate> </Page.Resources> <Page.DataContext> <Binding Source="{StaticResource Main}" /> </Page.DataContext> <Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}" Margin="20"> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" /> <ColumnDefinition Width="*" /> </Grid.ColumnDefinitions> <GridView ItemsSource="{Binding Items}" ItemTemplate="{StaticResource DataTemplate1}" VerticalAlignment="Top"> <GridView.ItemsPanel> <ItemsPanelTemplate> <VariableSizedWrapGrid ItemHeight="150" ItemWidth="150" /> </ItemsPanelTemplate> </GridView.ItemsPanel> </GridView> <GridView Grid.Column="1" ItemsSource="{Binding Items}" ItemTemplate="{StaticResource DataTemplate1}" VerticalAlignment="Top"> <GridView.ItemsPanel> <ItemsPanelTemplate> <VariableSizedWrapGrid ItemHeight="100" ItemWidth="100" /> </ItemsPanelTemplate> </GridView.ItemsPanel> </GridView> </Grid> The MainViewModel looks like this: public class MainViewModel { public IList<Item> Items { get; private set; } public MainViewModel() { Items = new List<Item> { new Item { Brush = new SolidColorBrush(Colors.Red) }, new Item { Brush = new SolidColorBrush(Colors.Blue) }, new Item { Brush = new SolidColorBrush(Colors.Green), }, // And more... }; } } As for the Item class, I am using an MVVM Light ObservableObject but you can use your own simple implementation of INotifyPropertyChanged of course: public class Item : ObservableObject { public const string ColSpanPropertyName = "ColSpan"; private int _colSpan = 1; public int ColSpan { get { return _colSpan; } set { Set(ColSpanPropertyName, ref _colSpan, value); } } public SolidColorBrush Brush { get; set; } public string BrushCode { get { return Brush.Color.ToString(); } } } Then I copied the GridViewItem’s style locally. To do this, I use Expression Blend’s functionality. It has the disadvantage to copy a large portion of XAML to your application, but the HUGE advantage to allow you to change the look and feel of your GridViewItem everywhere in the application. For example, you can change the selection chrome, the item’s alignments and many other properties. Actually everytime I use a ListBox, ListView or any other data control, I typically copy the item style to a resource dictionary in my application and I tweak it. Note that Blend for Windows 8 apps is automatically installed with every edition of Visual Studio 2012 (including Express) so you have no excuses anymore not to use Blend :) Open MainPage.xaml in Expression Blend by right clicking on the MainPage.xaml file in the Solution Explorer and selecting Open in Blend from the context menu. Note that the items do not look very nice! The reason is that the default ItemContainerStyle sets the content’s alignment to “Center” which I never quite understood. Seems to me that you rather want the content to be stretched, but anyway it is easy to change. Right click on the GridView on the left and select Edit Additional Templates, Edit Generated Item Container (ItemContainerStyle), Edit a Copy. In the Create Style Resource dialog, enter the name “DefaultGridViewItemStyle”, select “Application” and press OK. Side note 1: You need to save in a global resource dictionary because later we will need to retrieve that Style from a global location. Side note 2": I would rather copy the style to an external resource dictionary that I link into the App.xaml file, but I want to keep things simple here. Blend switches in Template edit mode. The template you are editing now is inside the ItemContainerStyle and will govern the appearance of your items. This is where, for instance, the “checked” chrome is defined, and where you can alter it if you need to. Note that you can reuse this style for all your GridViews even if you use a different DataTemplate for your items. Makes sense? I probably need to think about writing another blog post dedicated to the ItemContainerStyle :) In the breadcrumb bar on top of the page, click on the style icon. The property we want to change now can be changed in the Style instead of the Template, which is a better idea. Blend is not in Style edit mode, as you can see in the Objects and Timeline pane. In the Properties pane, in the Search box, enter the word “content”. This will filter all the properties containing that partial string, including the two we are interested in: HorizontalContentAlignment and VerticalContentAlignment. Set these two values to “Stretch” instead of the default “Center”. Using the breadcrumb bar again, set the scope back to the Page (by clicking on the first crumb on the left). Notice how the items are now showing as squares in the first GridView. We will now use the same ItemContainerStyle for the second GridView. To do this, right click on the second GridView and select Edit Additional Templates, Edit Generate Item Container, Apply Resource, DefaultGridViewItemStyle. The page now looks nicer: And now for the ColumnSpan! So now, let’s change the ColumnSpan property. First, let’s define a new Style that inherits the ItemContainerStyle we created before. Make sure that you save everything in Blend by pressing Ctrl-Shift-S. Open App.xaml in Visual Studio. Below the newly created DefaultGridViewItemStyle resource, add the following style: <Style x:Key="WideGridViewItemStyle" TargetType="GridViewItem" BasedOn="{StaticResource DefaultGridViewItemStyle}"> <Setter Property="VariableSizedWrapGrid.ColumnSpan" Value="2" /> </Style> Add a new class to the project, and name it MainItemStyleSelector. Implement the class as follows: public class MainItemStyleSelector : StyleSelector { protected override Style SelectStyleCore(object item, DependencyObject container) { var i = (Item)item; if (i.ColSpan == 2) { return Application.Current.Resources["WideGridViewItemStyle"] as Style; } return Application.Current.Resources["DefaultGridViewItemStyle"] as Style; } } In MainPage.xaml, add a resource to the Page.Resources section: <local:MainItemStyleSelector x:Key="MainItemStyleSelector" /> In MainPage.xaml, replace the ItemContainerStyle property on the first GridView with the ItemContainerStyleSelector property, pointing to the StaticResource we just defined. <GridView ItemsSource="{Binding Items}" ItemTemplate="{StaticResource DataTemplate1}" VerticalAlignment="Top" ItemContainerStyleSelector="{StaticResource MainItemStyleSelector}"> <GridView.ItemsPanel> <ItemsPanelTemplate> <VariableSizedWrapGrid ItemHeight="150" ItemWidth="150" /> </ItemsPanelTemplate> </GridView.ItemsPanel> </GridView> Do the same for the second GridView as well. Finally, in the MainViewModel, change the ColumnSpan property on the 3rd Item to 2. new Item { Brush = new SolidColorBrush(Colors.Green), ColSpan = 2 }, Running the application now creates the following image, which is what we wanted. Notice how the green item is now a “wide tile”. You can also experiment by creating different Styles, all inheriting the DefaultGridViewItemStyle and using different values of RowSpan for instance. This will allow you to create any layout you want, while leaving the heavy lifting of “flowing the layout” to the GridView control. What about changing these values dynamically? Of course as we can see in the Start menu, it would be nice to be able to change the ColumnSpan and maybe even the RowSpan values at runtime. Unfortunately at this time I have not found a good way to do that. I am investigating however and will make sure to post a follow up when I find what I am looking for! Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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Correct way to inject dependencies in Business logic service?

- by Sri Harsha Velicheti

Currently the structure of my application is as below Web App -- WCF Service (just a facade) -- Business Logic Services -- Repository - Entity Framework Datacontext Now each of my Business logic service is dependent on more than 5 repositories ( I have interfaces defined for all the repos) and I am doing a Constructor injection right now(poor mans DI instead of using a proper IOC as it was determined that it would be a overkill for our project). Repositories have references to EF datacontexts. Now some of the methods in the Business logic service require only one of the 5 repositories, so If I need to call that method I would end up instantiating a Service which will instatiate all 5 repositories which is a waste. An example: public class SomeService : ISomeService { public(IFirstRepository repo1, ISecondRepository repo2, IThirdRepository repo3) {} // My DoSomething method depends only on repo1 and doesn't use repo2 and repo3 public DoSomething() { //uses repo1 to do some stuff, doesn't use repo2 and repo3 } public DoSomething2() { //uses repo2 and repo3 to do something, doesn't require repo1 } public DoSomething3() { //uses repo3 to do something, doesn't require repo1 and repo2 } } Now if my I have to use DoSomething method on SomeService I end up creating both IFirstRepository,ISecondRepository and IThirdRepository but using only IFirstRepository, now this is bugging me, I can seem to accept that I am un-necessarily creating repositories and not using them. Is this a correct design? Are there any better alternatives? Should I be looking at Lazy instantiation Lazy<T> ?

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WPF, UserControl, and Commands? Oh my!

- by Greg D

(This question is related to another one, but different enough that I think it warrants placement here.) Here's a (heavily snipped) Window: <Window x:Class="Gmd.TimeTracker2.TimeTrackerMainForm" xmlns:local="clr-namespace:Gmd.TimeTracker2" xmlns:localcommands="clr-namespace:Gmd.TimeTracker2.Commands" x:Name="This" DataContext="{Binding ElementName=This}"> <Window.CommandBindings> <CommandBinding Command="localcommands:TaskCommands.ViewTaskProperties" Executed="HandleViewTaskProperties" CanExecute="CanViewTaskPropertiesExecute" /> </Window.CommandBindings> <DockPanel>  <Grid> <Grid.RowDefinitions> <RowDefinition /> <RowDefinition Height="Auto" /> </Grid.RowDefinitions>  <Button Content="_Create a new task" Grid.Row="1" x:Name="btnAddTask" Click="HandleNewTaskClick" /> </Grid> </DockPanel> </Window> and here's a (heavily snipped) UserControl: <UserControl x:Class="Gmd.TimeTracker2.TaskStopwatchControl" xmlns:local="clr-namespace:Gmd.TimeTracker2" xmlns:localcommands="clr-namespace:Gmd.TimeTracker2.Commands" x:Name="This" DataContext="{Binding ElementName=This}"> <UserControl.ContextMenu> <ContextMenu> <MenuItem x:Name="mnuProperties" Header="_Properties" Command="{x:Static localcommands:TaskCommands.ViewTaskProperties}" CommandTarget="What goes here?" /> </ContextMenu> </UserControl.ContextMenu> <StackPanel> <TextBlock MaxWidth="100" Text="{Binding Task.TaskName, Mode=TwoWay}" TextWrapping="WrapWithOverflow" TextAlignment="Center" /> <TextBlock Text="{Binding Path=ElapsedTime}" TextAlignment="Center" /> <Button Content="{Binding Path=IsRunning, Converter={StaticResource boolToString}, ConverterParameter='Stop Start'}" Click="HandleStartStopClicked" /> </StackPanel> </UserControl> Through various techniques, a UserControl can be dynamically added to the Window. Perhaps via the Button in the window. Perhaps, more problematically, from a persistent backing store when the application is started. As can be seen from the xaml, I've decided that it makes sense for me to try to use Commands as a way to handle various operations that the user can perform with Tasks. I'm doing this with the eventual goal of factoring all command logic into a more formally-defined Controller layer, but I'm trying to refactor one step at a time. The problem that I'm encountering is related to the interaction between the command in the UserControl's ContextMenu and the command's CanExecute, defined in the Window. When the application first starts and the saved Tasks are restored into TaskStopwatches on the Window, no actual UI elements are selected. If I then immediately r-click a UserControl in the Window in an attempt to execute the ViewTaskProperties command, the CanExecute handler never runs and the menu item remains disabled. If I then click some UI element (e.g., the button) just to give something focus, the CanExecute handlers are run with the CanExecuteRoutedEventArgs's Source property set to the UI element that has the focus. In some respect, this behavior seems to be known-- I've learned that menus automat

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How is WPF Data Binding using Object Data Source in Visual Studio 2010 done?

- by Rob Perkins

This is probably mostly a question about how to use the VS 2010 IDE tools in a way the Microsofties didn't specifically intend. But since this is something I immediately tried without success. I have defined a .NET 4.0 WPF Application project with a simple class that looks like this: Public Class Class1 Public Property One As String = "OneString" Public Property Two As String = "TwoString" End Class I then defined it as an "Object Data Source" in VS2010, using the IDE's "Add New Data Source..." feature. This exposes the class members in a GUI element in the IDE as given in this image: Dragging "Class1" from that tool to the surface of "Window1.xaml" in a default "WPF Application" results in the design view looking like this: And generated XAML like this: <Window x:Class="Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="133" Width="170" xmlns:my="clr-namespace:WpfApplication1" mc:Ignorable="d" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" > <Window.Resources> <CollectionViewSource x:Key="Class1ViewSource" d:DesignSource="{d:DesignInstance my:Class1, CreateList=True}" /> </Window.Resources> <Grid DataContext="{StaticResource Class1ViewSource}" HorizontalAlignment="Left" Name="Grid1" VerticalAlignment="Top"> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" /> <ColumnDefinition Width="Auto" /> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="Auto" /> <RowDefinition Height="Auto" /> </Grid.RowDefinitions> <Label Content="One:" Grid.Column="0" Grid.Row="0" HorizontalAlignment="Left" Margin="3" VerticalAlignment="Center" /> <TextBlock Grid.Column="1" Grid.Row="0" Height="23" HorizontalAlignment="Left" Margin="3" Name="OneTextBlock" Text="{Binding Path=One}" VerticalAlignment="Center" /> <Label Content="Two:" Grid.Column="0" Grid.Row="1" HorizontalAlignment="Left" Margin="3" VerticalAlignment="Center" /> <TextBlock Grid.Column="1" Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="3" Name="TwoTextBlock" Text="{Binding Path=Two}" VerticalAlignment="Center" /> </Grid> Note the data bindings Text="{Binding Path=One}" and Text="{Binding Path=Two}" in the TextBlock elements. Code-behind for Window1.xaml has this in Window_Loaded: Class Window1 Private m_c1 As New Class1 Private Sub Window1_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles Me.Loaded Dim Class1ViewSource As System.Windows.Data.CollectionViewSource = CType(Me.FindResource("Class1ViewSource"), System.Windows.Data.CollectionViewSource) 'Load data by setting the CollectionViewSource.Source property: 'Class1ViewSource.Source = [generic data source] Me.DataContext = m_c1 End Sub End Class Running the application produces this output: The expected result was that "OneString" would appear next to "One" and "TwoString" next to "Two" in the running window. The question is: Why didn't this work? What will work instead? If I put bindings in a DataTemplate, it works. Blend, with its sample data stuff, implied that this should work, but it doesn't. I know I'm missing something pretty fundamental here; what is it?

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WFP: How do you properly Bind a DependencyProperty to the GUI

- by Robert Ross

I have the following class (abreviated for simplicity). The app it multi-threaded so the Set and Get are a bit more complicated but should be ok. namespace News.RSS { public class FeedEngine : DependencyObject { public static readonly DependencyProperty _processing = DependencyProperty.Register("Processing", typeof(bool), typeof(FeedEngine), new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsRender)); public bool Processing { get { return (bool)this.Dispatcher.Invoke( DispatcherPriority.Normal, (DispatcherOperationCallback)delegate { return GetValue(_processing); }, Processing); } set { this.Dispatcher.BeginInvoke(DispatcherPriority.Normal, (SendOrPostCallback)delegate { SetValue(_processing, value); }, value); } } public void Poll() { while (Running) { Processing = true; //Do my work to read the data feed from remote source Processing = false; Thread.Sleep(PollRate); } // } } } Next I have my main form as the following: <Window x:Class="News.Main" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:converter="clr-namespace:News.Converters" xmlns:local="clr-namespace:News.Lookup" xmlns:rss="clr-namespace:News.RSS" Title="News" Height="521" Width="927" Initialized="Window_Initialized" Closing="Window_Closing" > <Window.Resources> <ResourceDictionary> <converter:BooleanConverter x:Key="boolConverter" /> <converter:ArithmeticConverter x:Key="arithConverter" /> ... </ResourceDictionary> </Window.Resources> <DockPanel Name="dockPanel1" SnapsToDevicePixels="False" > <ToolBarPanel Height="37" Name="toolBarPanel" Orientation="Horizontal" DockPanel.Dock="Top" > <ToolBarPanel.Children> <Button DataContext="{DynamicResource FeedEngine}" HorizontalAlignment="Right" Name="btnSearch" ToolTip="Search" Click="btnSearch_Click" IsEnabled="{Binding Path=Processing, Converter={StaticResource boolConverter}}"> <Image Width="32" Height="32" Name="imgSearch" Source="{Resx ResxName=News.Properties.Resources, Key=Search}" /> </Button> ... </DockPanel> </Window> As you can see I set the DataContext to FeedEngine and Bind IsEnabled to Processing. I have also tested the boolConverter separately and it functions (just applies ! (Not) to a bool). Here is my Main window code behind in case it helps to debug. namespace News { /// <summary> /// Interaction logic for Main.xaml /// </summary> public partial class Main : Window { public FeedEngine _engine; List<NewsItemControl> _newsItems = new List<NewsItemControl>(); Thread _pollingThread; public Main() { InitializeComponent(); this.Show(); } private void Window_Initialized(object sender, EventArgs e) { // Load current Feed data. _engine = new FeedEngine(); ThreadStart start = new ThreadStart(_engine.Poll); _pollingThread = new Thread(start); _pollingThread.Start(); } } } Hope someone can see where I missed a step. Thanks.

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CommandBinding broken in inner Custom Control when nesting two Custom Controls of the same type.

- by Fredrik Eriksson

I've done a Custom Control in form of a GroupBox but with an extra header which purpose is to hold a button or a stackpanel with buttons at the other side. I've added the a Dependency Property to hold the extra header and I've connected the customized template. Everything works fine until I put one of these controls in another one. Now the wierd stuff begins(at least in my eyes xP), the command binding in the inner control simply isn't set. I tried to use Snoop to gather some data, the see if the inherits is broken and when I clicked on the buttons which isn't doing what I want it to, boom, breakpoint triggered. So in some wierd way the Command isn't set until something that I don't know what it is, happens, which snoops triggers. I've also tried to put the buttons in the regular Header property and that works fine, but not with my own made. I could just switch places with them to make it like I want but now I'm curious to know where the problem lies... Now I wonder, what can I've missed? The control class: public class TwoHeaderedGroupBox : GroupBox { static TwoHeaderedGroupBox() { DefaultStyleKeyProperty.OverrideMetadata(typeof(TwoHeaderedGroupBox), new FrameworkPropertyMetadata(typeof(TwoHeaderedGroupBox))); } public static DependencyProperty HeaderTwoProperty = DependencyProperty.Register("HeaderTwo", typeof(object), typeof(TwoHeaderedGroupBox), new FrameworkPropertyMetadata()); public object HeaderTwo { get { return (object)GetValue(HeaderTwoProperty); } set { SetValue(HeaderTwoProperty, value);} } } And here is the Template (which by the way is created by blend from the beginning): <ControlTemplate TargetType="{x:Type Controls:TwoHeaderedGroupBox}"> <Grid SnapsToDevicePixels="true"> <Grid.ColumnDefinitions> <ColumnDefinition Width="6"/> <ColumnDefinition Width="Auto"/> <ColumnDefinition Width="*"/> <ColumnDefinition Width="6"/> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> <RowDefinition Height="6"/> </Grid.RowDefinitions> <Border BorderBrush="Transparent" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Grid.ColumnSpan="4" Grid.Column="0" CornerRadius="4" Grid.Row="1" Grid.RowSpan="3"/> <Border x:Name="Header" Grid.Column="1" Padding="3,1,3,0" Grid.Row="0" Grid.RowSpan="2" VerticalAlignment="Center"> <ContentControl Content="{TemplateBinding Header}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/> </Border> <ContentPresenter Grid.ColumnSpan="2" Grid.Column="1" Margin="{TemplateBinding Padding}" Grid.Row="2" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/> <Border BorderBrush="White" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="4" CornerRadius="4" Grid.Row="1" Grid.RowSpan="3"> <Border.OpacityMask> <MultiBinding ConverterParameter="7" Converter="{StaticResource BorderGapMaskConverter}"> <Binding ElementName="Header" Path="ActualWidth"/> <Binding Path="ActualWidth" RelativeSource="{RelativeSource Self}"/> <Binding Path="ActualHeight" RelativeSource="{RelativeSource Self}"/> </MultiBinding> </Border.OpacityMask> <Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="3"> <Border BorderBrush="White" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="2"/> </Border> </Border> <Border x:Name="HeaderTwo" Grid.Column="2" Padding="3,5,3,5" Grid.Row="0" Grid.RowSpan="2" HorizontalAlignment="Right"> <ContentControl Content="{TemplateBinding HeaderTwo}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" DataContext="{TemplateBinding DataContext}"/> </Border> </Grid> </ControlTemplate>

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WPF: Focus in a Window and UserControl

- by Echilon

I'm trying to get a UserControl to tab properly and am baffled. The logical tree looks like this. |-Window -Grid -TabControl -TabItem -StackPanel -MyUserControl |-StackPanel -GroupBox -Grid -ComboBox -Textbox1 -Textbox2 Everything works fine, except when the visibility converter for the ComboBox returns Visibility.Collapsed (don't allow user to change database mode), then when textbox1 is selected, instead of being able to tab through the controls in the UserControl, the focus shifts to a button declared at the bottom of the window. Nothing else apart from the controls displayed has TabIndex or FocusManager properties set. I'm banging my head against a brick wall and I must be missing something. I've tried IsFocusScope=True/False, played with FocusedElement and nothing works if that ComboBox is invisible (Visibility.Collapsed). <Window x:Class="MyNamespace.Client.WinInstaller" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" FocusManager.FocusedElement="{Binding ElementName=tabWizard}"> <Window.Resources> <props:Settings x:Key="settings" /> </Window.Resources> <Grid Grid.IsSharedSizeScope="True">  <loc:SmallHeader Grid.Row="0" x:Name="headerBranding" HeaderText="Setup" /> <TabControl x:Name="tabWizard" DataContext="{StaticResource settings}" SelectedIndex="0" FocusManager.IsFocusScope="True"> <TabItem x:Name="tbStart" Height="0"> <StackPanel> <TextBlock Text="Database Mode"/> <loc:DatabaseSelector x:Name="dbSelector" AllowChangeMode="False" TabIndex="1" AvailableDatabaseModes="SQLServer" IsPortRequired="False" DatabaseMode="{Binding Default.DbMode,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" DatabasePath="{Binding Default.DatabasePath,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"/> </StackPanel> </TabItem> ... The top of the user control is below: <UserControl x:Class="MyNamespace.Client.DatabaseSelector" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Name="root" FocusManager.IsFocusScope="True" FocusManager.FocusedElement="{Binding ElementName=cboDbMode}"> <UserControl.Resources> <conv:DatabaseModeIsFileBased x:Key="DatabaseModeIsFileBased"/> <BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/> </UserControl.Resources> <StackPanel DataContext="{Binding}"> <GroupBox> <Grid>  <Label Content="Database Mode"/> <ComboBox x:Name="cboDbMode" SelectedValue="{Binding ElementName=root,Path=DatabaseMode,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" DisplayMemberPath="Value" SelectedValuePath="Key" TabIndex="1" Visibility="{Binding AllowChangeMode,ElementName=root,Converter={StaticResource BooleanToVisibilityConverter}}" />  <Grid> <Label "Host"/> <TextBox x:Name="txtDBHost" Text="{Binding ElementName=root,Path=DatabaseHost,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" TabIndex="2" /> <TextBox x:Name="txtDBPort" Text="{Binding ElementName=root,Path=DatabasePortString,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" TabIndex="3" />

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WPF DataTemplateKey can not find ListBox key

- by Ryan

I am fairly new to WPF and am having trouble getting the DataTemplateKey to find my ListBox. <Window.Resources> <ControlTemplate x:Key="FocusTemplate" > <Rectangle Fill="Azure" Width="290" Height="55" /> </ControlTemplate> <Style x:Key="FocusStyle" TargetType="{x:Type Control}"> <Setter Property="Template" Value="{StaticResource FocusTemplate}"/> </Style> <Style TargetType="ListBoxItem"> <EventSetter Event="GotFocus" Handler="ListItem_GotFocus"></EventSetter> </Style> <DataTemplate DataType="{x:Type TextBlock}"> </DataTemplate> <DataTemplate x:Key="CustomListData" DataType="{x:Type ListBox}"> <Border BorderBrush="Black" BorderThickness="1" Margin="-2,0,0,-1"> <Grid> <Grid.RowDefinitions> <RowDefinition Height="55*" /> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" /> <ColumnDefinition Width="*" /> </Grid.ColumnDefinitions> <Grid.RenderTransform> <TransformGroup> <ScaleTransform ScaleX="1" ScaleY="1"/> <SkewTransform AngleX="0" AngleY="0"/> <RotateTransform Angle="0"/> <TranslateTransform X="0" Y="0"/> </TransformGroup> </Grid.RenderTransform>  <TextBox Width="290" TextAlignment="Left" VerticalContentAlignment="Center" BorderThickness="0" BorderBrush="Transparent" Foreground="#FF6FB8FD" FontSize="18" FocusVisualStyle="{StaticResource FocusStyle}" Name="editingBox" TextWrapping="Wrap" Text="{Binding .}" Grid.Column="1" Grid.Row="1" MinHeight="55" Cursor="Hand" IsReadOnly="True" > <TextBox.Background> <LinearGradientBrush EndPoint="0,1" StartPoint="0,0"> <LinearGradientBrush.RelativeTransform> <TransformGroup> <ScaleTransform CenterX="0.5" CenterY="0.5"/> <SkewTransform CenterX="0.5" CenterY="0.5"/> <RotateTransform Angle="0" CenterX="0.5" CenterY="0.5"/> <TranslateTransform/> </TransformGroup> </LinearGradientBrush.RelativeTransform> <GradientStop Color="#FF2D4984"/> <GradientStop Color="#FF182D56" Offset="0.042"/> </LinearGradientBrush> </TextBox.Background> </TextBox> </Grid> </Border> </DataTemplate> <Style TargetType="{x:Type ListBox}"> <Setter Property="ItemTemplate" Value="{StaticResource CustomListData }" /> <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Disabled" /> </Style> </Window.Resources> <Window.DataContext> <ObjectDataProvider ObjectType="{x:Type local:ImageLoader}" MethodName="LoadImages" /> </Window.DataContext> <ListBox ItemsSource="{Binding}" Width="320" Background="#FF021422" BorderBrush="#FF1C4B79"> <ListBox.Resources> <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}">Transparent</SolidColorBrush> </ListBox.Resources> </ListBox> The following code will find a TextBlock var key = new System.Windows.DataTemplateKey(typeof(TextBlock)); var r = (DataTemplate)this.FindResource(key); However, when I change the type to ListBox, the key can not be found. What have I missed? Thanks Ryan

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Silverlight: Binding a custom control to an arbitrary object

- by Ryan Bates

I am planning on writing a hierarchical organizational control, similar to an org chart. Several org chart implementations are out there, but not quite fit what I have in mind. Binding fields in a DataTemplate to a custom object does not seem to work. I started with a generic, custom control, i.e. public class NodeBodyBlock : ContentControl { public NodeBodyBlock() { this.DefaultStyleKey = typeof(NodeBodyBlock); } } It has a simple style in generic.xaml: <Style TargetType="org:NodeBodyBlock"> <Setter Property="Width" Value="200" /> <Setter Property="Height" Value="100" /> <Setter Property="Background" Value="Lavender" /> <Setter Property="FontSize" Value="11" /> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="org:NodeBodyBlock"> <Border Width="{TemplateBinding Width}" Height="{TemplateBinding Height}" Background="{TemplateBinding Background}" CornerRadius="4" BorderBrush="Black" BorderThickness="1" > <Grid> <VisualStateManager/> ... clipped for brevity </VisualStateManager.VisualStateGroups> <ContentPresenter Content="{TemplateBinding Content}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" /> </Grid> </Border> </ControlTemplate> </Setter.Value> </Setter> </Style> My plan now is to be able to use this common definition as a base definition of sorts, with customized version of it used to display different types of content. A simple example would be to use this on a user control with the following style: <Style TargetType="org:NodeBodyBlock" x:Key="TOCNode2"> <Setter Property="ContentTemplate"> <Setter.Value> <DataTemplate> <StackPanel> <TextBlock Text="{Binding Path=NodeTitle}"/> </StackPanel> </DataTemplate> </Setter.Value> </Setter> </Style> and an instance defined as <org:NodeBodyBlock Style="{StaticResource TOCNode2}" x:Name="stTest" DataContext="{StaticResource DummyData}" /> The DummyData is defined as <toc:Node NodeNumber="mynum" NodeStatus="A" NodeTitle="INLine Node Title!" x:Key="DummyData"/> With a simple C# class behind it, where each of the fields is a public property. When running the app, the Dummy Data values simply do not show up in the GUI. A trivial test such as <TextBlock Text="{Binding NodeTitle}" DataContext="{StaticResource DummyData}"/> works just fine. Any ideas around where I am missing the plot?

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WP7 listbox binding not working properly

- by Marco

A noob error for sure (I started yesterday afternoon developing in WP7), but I'm wasting a lot time on it. I post my class and a little part of my code: public class ChronoLaps : INotifyPropertyChanged { private ObservableCollection<ChronoLap> laps = null; public int CurrentLap { get { return lap; } set { if (value == lap) return; // Some code here .... ChronoLap newlap = new ChronoLap() { // Some code here ... }; Laps.Insert(0, newlap); lap = value; NotifyPropertyChanged("CurrentLap"); NotifyPropertyChanged("Laps"); } } public ObservableCollection<ChronoLap> Laps { get { return laps; } set { if (value == laps) return; laps = value; if (laps != null) { laps.CollectionChanged += delegate { MeanTime = Laps.Sum(p => p.Time.TotalMilliseconds) / (Laps.Count * 1000); NotifyPropertyChanged("MeanTime"); }; } NotifyPropertyChanged("Laps"); } } } MainPage.xaml.cs public partial class MainPage : PhoneApplicationPage { public ChronoLaps History { get; private set; } private void butStart_Click(object sender, EventArgs e) { History = new ChronoLaps(); // History.Laps.Add(new ChronoLap() { Distance = 0 }); LayoutRoot.DataContext = History; } } MainPage.xaml <phone:PhoneApplicationPage> <Grid x:Name="LayoutRoot" Background="Transparent"> <Grid Grid.Row="2"> <ScrollViewer Margin="-5,13,3,36" Height="758"> <ListBox Name="lbHistory" ItemContainerStyle="{StaticResource ListBoxStyle}" ItemsSource="{Binding Laps}" HorizontalAlignment="Left" Margin="5,25,0,0" VerticalAlignment="Top" Width="444"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <TextBlock Text="{Binding Lap}" Width="40" /> <TextBlock Text="{Binding Time}" Width="140" /> <TextBlock Text="{Binding TotalTime}" Width="140" /> <TextBlock Text="{Binding Distance}" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> </ScrollViewer> </Grid> </Grid> </phone:PhoneApplicationPage> Problem is that when I add one or more items to History.Laps collection, my listbox is not refreshed and these items don't appear. But if I remove comment on // History.Laps.Add(new ChronoLap()... line, this item appear and so every other inserted later. More: if I remove that comment and then write History.Laps.Clear() (before or after setting binding) binding is not working anymore. It's like it gets crazy if collection is empty. I really don't understand the reason... UPDATE AND SOLUTION: If i move History = new ChronoLaps(); LayoutRoot.DataContext = History; from butStart_Click to public MainPage() everything works as expected. Can someone explain me the reason?

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Getting code-first Entity Framework to build tables on SQL Azure

- by NER1808

I am new the code-first Entity Framework. I have tried a few things now, but can't get EF to construct any tables in the my SQL Azure database. Can anyone advise of some steps and settings I should check. The membership provider has no problems create it's tables. I have added the PersistSecurityInfo=True in the connection string. The connection string is using the main user account for the server. When I implement the tables in the database using sql everything works fine. I have the following in the WebRole.cs //Initialize the database Database.SetInitializer<ReykerSCPContext>(new DbInitializer()); My DbInitializer (which does not get run before I get a "Invalid object name 'dbo.ClientAccountIFAs'." when I try to access the table for the first time. Sometime after startup. public class DbInitializer:DropCreateDatabaseIfModelChanges<ReykerSCPContext> { protected override void Seed(ReykerSCPContext context) { using (context) { //Add Doc Types context.DocTypes.Add(new DocType() { DocTypeId = 1, Description = "Statement" }); context.DocTypes.Add(new DocType() { DocTypeId = 2, Description = "Contract note" }); context.DocTypes.Add(new DocType() { DocTypeId = 3, Description = "Notification" }); context.DocTypes.Add(new DocType() { DocTypeId = 4, Description = "Invoice" }); context.DocTypes.Add(new DocType() { DocTypeId = 5, Description = "Document" }); context.DocTypes.Add(new DocType() { DocTypeId = 6, Description = "Newsletter" }); context.DocTypes.Add(new DocType() { DocTypeId = 7, Description = "Terms and Conditions" }); //Add ReykerAccounttypes context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 1, Description = "ISA" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 2, Description = "Trading" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 3, Description = "SIPP" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 4, Description = "CTF" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 5, Description = "JISA" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 6, Description = "Direct" }); context.ReykerAccountTypes.Add(new ReykerAccountType() { ReykerAccountTypeID = 7, Description = "ISA & Direct" }); //Save the changes context.SaveChanges(); } and my DBContext class looks like public class ReykerSCPContext : DbContext { //set the connection explicitly public ReykerSCPContext():base("ReykerSCPContext"){} //define tables public DbSet<ClientAccountIFA> ClientAccountIFAs { get; set; } public DbSet<Document> Documents { get; set; } public DbSet<DocType> DocTypes { get; set; } public DbSet<ReykerAccountType> ReykerAccountTypes { get; set; } protected override void OnModelCreating(DbModelBuilder modelBuilder) { //Runs when creating the model. Can use to define special relationships, such as many-to-many. } The code used to access the is public List<ClientAccountIFA> GetAllClientAccountIFAs() { using (DataContext) { var caiCollection = from c in DataContext.ClientAccountIFAs select c; return caiCollection.ToList(); } } and it errors on the last line. Help!

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Binding Combobox to XML (wpf)

- by mortor

<EssenceList> <Essence GUID="464"> <Properties> <Property Name="Name"> <value>mt-1232-1. (1-1-3)</value> </Property> </Properties> <Characteristics> <Characteristic GUID="78"> <value>gadget</value> </Characteristic> <Characteristic GUID="79"> <value>measures</value> </Characteristic> </Characteristics> <LinkedEssences> <LinkType Type="ObjGroup"> <LinkedEssence GUID="369" /> </LinkType> <LinkType Type="ObjGroupProp" /> <LinkType Type="RoleObject"> <LinkedEssence GUID="5747"/> </LinkType> </LinkedEssences> </Essence> ... <Essence GUID="5747" Type="Role"> <Properties> <Property Name="Name"> <value>????-22</value> </Property> <Property Name="ShortName"> <value>UKPG-22</value> </Property> <Property Name="TagPrefix"> <value>UKPG22</value> </Property> <Property Name="useParentTagPrefix"> <value>0</value> </Property> </Properties> </Essence> ... <Essence GUID="5748" Type="Role"> </Essence> ... in example is a xml file with data from database. now i need to bind it to some fields... i use the XMLDataProvider here <Grid.DataContext> <XmlDataProvider x:Name="dataxml" XPath="EssenceList/Essence" Source="464.xml"/> </Grid.DataContext> and mostof simple texboxes i bind like <TextBox Text="{Binding XPath=/EssenceList/Essence/LinkedEssences/LinkType[1]/LinkedEssence/@GUID}" /> but now i need to bind a combobox this way: - the first Essence in the document contains LinkedEssences, that contains and - in document below there is a full description for it that contains the NAME property i need ????-22 UKPG22 0 and many other available Essences for this combobox i managed to bind the list of thems to combobox <ComboBox ItemTemplate="{StaticResource rolelistTemplate}" ItemsSource="{Binding XPath=/EssenceList/Essence[@Type]}" /> so it displays it well, but i can't bind it to my LinkedEssences.

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strange sqares like hints in Silverlight application?

- by lina

Good day! Strange square appears on mouse hover on text boxes, buttons, etc (something like hint) in a silverlight navigation application - how can I remove it? a scrin shot an example .xaml page: <Code:BasePage x:Class="CAP.Views.Main" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" mc:Ignorable="d" xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation" xmlns:Code="clr-namespace:CAP.Code" d:DesignWidth="640" d:DesignHeight="480" Title="?????? ??????? ???????? ??? ?????"> <Grid x:Name="LayoutRoot"> <Grid.RowDefinitions> <RowDefinition Height="103*" /> <RowDefinition Height="377*" /> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="120*" /> <ColumnDefinition Width="520*" /> </Grid.ColumnDefinitions> <Image Height="85" HorizontalAlignment="Left" Name="image1" Stretch="Fill" VerticalAlignment="Top" Width="84" Margin="12,0,0,0" ImageFailed="image1_ImageFailed" Source="/CAP;component/Images/My-Computer.png" /> <TextBlock Grid.Column="1" Height="Auto" TextWrapping="Wrap" HorizontalAlignment="Left" Margin="0,12,0,0" Name="textBlock1" Text="Good day!" VerticalAlignment="Top" FontFamily="Verdana" FontSize="16" Width="345" FontWeight="Bold" /> <TextBlock Grid.Column="1" Grid.Row="1" TextWrapping="Wrap" Height="299" HorizontalAlignment="Left" Name="textBlock2" VerticalAlignment="Top" FontFamily="Verdana" FontSize="14" Width="441" > <Run Text="Some text "/><LineBreak/><LineBreak/><Run Text="and so on"/> <LineBreak/> </TextBlock> </Grid> xaml.cs: using System; using System.Collections.Generic; using System.Linq; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; using System.Windows.Navigation; using CAP.Code; namespace CAP.Views { public partial class Main : BasePage { public Main() : base() { InitializeComponent(); MapBuilder.AddToMap(new SiteMapUnit() { Caption = "???????", RelativeUrl = "Main" },true); ((App)Application.Current).Mainpage.tvMainMenu.SelectedItems.Clear(); } // Executes when the user navigates to this page. protected override void OnNavigatedTo(NavigationEventArgs e) { } private void image1_ImageFailed(object sender, ExceptionRoutedEventArgs e) { } protected override string[] NeededPermission() { return new string[0]; } } } MainPage.xaml <UserControl x:Class="CAP.MainPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Code="clr-namespace:CAP.Code" xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation" xmlns:uriMapper="clr-namespace:System.Windows.Navigation;assembly=System.Windows.Controls.Navigation" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:telerik="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls" xmlns:telerikNavigation="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Navigation" mc:Ignorable="d" Margin="0,0,0,0" Width="auto" Height="auto" xmlns:dataInput="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.Input"> <ScrollViewer Width="auto" Height="auto" BorderBrush="White" BorderThickness="0" Margin="0,0,0,0" x:Name="sV" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto" > <ScrollViewer.Content> <Grid Width="auto" Height="auto" x:Name="LayoutRoot" Style="{StaticResource LayoutRootGridStyle}" Margin="0,0,0,0"> <StackPanel Width="auto" Height="auto" Orientation="Vertical" Margin="250,0,0,50"> <Border x:Name="ContentBorder2" Margin="0,0,0,0" >  <StackPanel Orientation="Vertical" Height="82" Width="Auto" HorizontalAlignment="Right" Margin="0,0,0,0" DataContext="{Binding}"> <TextBlock HorizontalAlignment="Right" Foreground="White" x:Name="ApplicationNameTextBlock4" Style="{StaticResource ApplicationNameStyle}" FontSize="20" Text="?????? ???????" Margin="20,16,20,0"/> <StackPanel Orientation="Horizontal" HorizontalAlignment="Right"> <Image x:Name="imDoor" Visibility="Collapsed" MouseEnter="imDoor_MouseEnter" MouseLeave="imDoor_MouseLeave" Height="24" Stretch="Fill" Width="25" Margin="10,0,10,0" Source="/CAP;component/Images/sm_white_doors.png" MouseLeftButtonDown="bTest_Click" /> <TextBlock x:Name="bLogout" MouseEnter="bLogout_MouseEnter" MouseLeave="bLogout_MouseLeave" TextDecorations="Underline" Margin="0,6,20,4" Height="23" Text="?????" HorizontalAlignment="Right" Visibility="Collapsed" MouseLeftButtonDown="bTest_Click" FontFamily="Verdana" FontSize="13" FontWeight="Normal" Foreground="#FF1C1C92" /> </StackPanel> </StackPanel> </Border> <Border x:Name="bSiteMap" Margin="0,0,0,0" > <StackPanel x:Name="spSiteMap" Orientation="Horizontal" Height="20" Width="Auto" HorizontalAlignment="Left" Margin="0,0,0,0" DataContext="{Binding}">  </StackPanel> </Border> <Border Width="auto" Height="auto" x:Name="ContentBorder" Margin="0,0,0,0" > <navigation:Frame x:Name="ContentFrame" Style="{StaticResource ContentFrameStyle}" Source="Main" Navigated="ContentFrame_Navigated" NavigationFailed="ContentFrame_NavigationFailed" ToolTipService.ToolTip=" " Margin="0,0,0,0"> <navigation:Frame.UriMapper> <uriMapper:UriMapper>  <uriMapper:UriMapping Uri="RegistrateClient" MappedUri="/Views/Client/RegistrateClient.xaml"/>  </uriMapper:UriMapper> </navigation:Frame.UriMapper> </navigation:Frame> </Border> </StackPanel> <Grid x:Name="NavigationGrid" Style="{StaticResource NavigationGridStyle}" Margin="0,0,0,0" Background="{x:Null}" > <StackPanel Orientation="Vertical" Height="Auto" Width="250" HorizontalAlignment="Center" Margin="0,0,0,50" DataContext="{Binding}"> <Image Width="150" Height="90" HorizontalAlignment="Center" VerticalAlignment="Top" Source="/CAP;component/Images/logo__au.png" Margin="0,20,0,70"/> <Border x:Name="BrandingBorder" MinHeight="222" Width="250" Style="{StaticResource BrandingBorderStyle3}" HorizontalAlignment="Center" Opacity="60" Margin="0,0,0,0"> <Border.Background> <ImageBrush ImageSource="/CAP;component/Images/papka.png"/> </Border.Background> <Grid Width="250" x:Name="LichniyCabinet" Margin="0,10,0,0" HorizontalAlignment="Center" Height="211"> <Grid.ColumnDefinitions> <ColumnDefinition Width="19*" /> <ColumnDefinition Width="62*" /> <ColumnDefinition Width="151*" /> <ColumnDefinition Width="18*" /> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="13" /> <RowDefinition Height="24" /> <RowDefinition Height="35" /> <RowDefinition Height="35" /> <RowDefinition Height="43" /> <RowDefinition Height="28" /> <RowDefinition Height="32*" /> </Grid.RowDefinitions> <TextBlock Visibility="Visible" Grid.Row="2" Height="23" HorizontalAlignment="Left" x:Name="tLogin" Text="?????" VerticalAlignment="Top" FontFamily="Verdana" FontSize="13" Foreground="White" Margin="1,0,0,0" Grid.Column="1" /> <TextBlock Visibility="Visible" FontFamily="Verdana" FontSize="13" Foreground="White" Height="23" HorizontalAlignment="Left" x:Name="tPassw" Text="??????" VerticalAlignment="Top" Grid.Row="3" Grid.Column="1" /> <TextBox Visibility="Visible" Grid.Column="2" Grid.Row="2" Height="24" HorizontalAlignment="Left" x:Name="logLogin" VerticalAlignment="Top" Width="150" /> <PasswordBox Visibility="Visible" Code:DefaultButtonService.DefaultButton="{Binding ElementName=bLogin}" PasswordChar="*" Height="24" HorizontalAlignment="Left" x:Name="logPassword" VerticalAlignment="Top" Width="150" Grid.Column="2" Grid.Row="3" /> <Button x:Name="bLogin" MouseEnter="bLogin_MouseEnter" MouseLeave="bLogin_MouseLeave" Visibility="Visible" Content="?????" Grid.Column="2" Grid.Row="4" Click="Button_Click" Height="23" HorizontalAlignment="Left" Margin="81,0,0,0" VerticalAlignment="Top" Width="70" /> <TextBlock MouseLeftButtonDown="ForgotPassword_MouseLeftButtonDown" MouseEnter="ForgotPassword_MouseEnter" MouseLeave="ForgotPassword_MouseLeave" Visibility="Visible" TextDecorations="Underline" Grid.ColumnSpan="2" Grid.Row="4" Height="23" HorizontalAlignment="Left" x:Name="ForgotPassword" Text="?????? ???????" VerticalAlignment="Top" Foreground="White" FontFamily="Verdana" FontSize="13" Grid.Column="1" /> <TextBlock MouseEnter="tbRegistration_MouseEnter" MouseLeave="tbRegistration_MouseLeave" MouseLeftButtonDown="tbRegistration_MouseLeftButtonDown" Grid.Column="2" Grid.Row="6" Height="23" x:Name="tbRegistration" TextDecorations="Underline" Text="???????????" VerticalAlignment="Top" FontFamily="Verdana" FontSize="13" TextAlignment="Center" HorizontalAlignment="Center" Foreground="#FF1C1C92" FontWeight="Normal" Margin="0,0,57,0" /> <TextBlock Cursor="Arrow" Height="23" HorizontalAlignment="Left" Margin="11,-3,0,0" Text="?????? ???????" VerticalAlignment="Top" Grid.ColumnSpan="3" Grid.RowSpan="2" FontFamily="Verdana" FontSize="13" FontWeight="Bold" Foreground="White" /> <Image Visibility="Collapsed" Height="70" x:Name="imUser" Stretch="Fill" Width="70" Grid.ColumnSpan="2" Margin="11,0,0,0" Grid.Row="2" Grid.RowSpan="2" Source="/CAP;component/Images/user2.png" /> <TextBlock x:Name="tbHello" Grid.Column="2" Visibility="Collapsed" Grid.Row="2" Height="auto" TextWrapping="Wrap" HorizontalAlignment="Left" Margin="6,0,0,0" Text="" VerticalAlignment="Top" FontFamily="Verdana" FontSize="13" Foreground="White" Width="145" /> </Grid> </Border> <Border x:Name="MenuBorder" Margin="0,0,0,50" Width="250" Visibility="Collapsed"> <StackPanel x:Name="spMenu" Width="240" HorizontalAlignment="Left"> <telerikNavigation:RadTreeView x:Name="tvMainMenu" Width="240" Selected="TreeView1_Selected" SelectedValuePath="Text" telerik:Theming.Theme="Windows7" FontFamily="Verdana" FontSize="12"/> </StackPanel> </Border> </StackPanel> </Grid> <Border x:Name="FooterBorder" VerticalAlignment="Bottom" Width="auto" Height="76"> <Border.Background> <ImageBrush ImageSource="/CAP;component/Images/footer2.png" /> </Border.Background> <TextBlock x:Name="tbFooter" Height="24" Width="auto" Margin="0,20,0,0" TextAlignment="Center" HorizontalAlignment="Stretch" VerticalAlignment="Center" Foreground="White" FontFamily="Verdana" FontSize="11"> </TextBlock> </Border> </Grid> </ScrollViewer.Content> </ScrollViewer> </UserControl> MainPage.xaml.cs using System; using System.Collections.Generic; using System.Linq; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Navigation; using CAP.Code; using CAP.Registrator; using System.Windows.Input; using System.ComponentModel.DataAnnotations; using System.Windows.Browser; using Telerik.Windows.Controls; using System.Net; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Navigation; using System.Windows.Shapes; namespace CAP { public partial class MainPage { public App Appvars = Application.Current as App; private readonly RegistratorClient registrator; public SiteMapBuilder builder; public MainPage() { InitializeComponent(); sV.SetIsMouseWheelScrollingEnabled(true); builder = new SiteMapBuilder(spSiteMap); try { //working with service } catch { this.ContentFrame.Navigate(new Uri(String.Format("ErrorPage"), UriKind.RelativeOrAbsolute)); } } /// Recursive method to update the correct scrollviewer (if exists) private ScrollViewer CheckParent(FrameworkElement element) { ScrollViewer _result = element as ScrollViewer; if (element != null && _result == null) { FrameworkElement _temp = element.Parent as FrameworkElement; _result = CheckParent(_temp); } return _result; } // If an error occurs during navigation, show an error window private void ContentFrame_NavigationFailed(object sender, NavigationFailedEventArgs e) { e.Handled = true; ChildWindow errorWin = new ErrorWindow(e.Uri); errorWin.Show(); } } }

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