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  • These are few objective type questions which i was not able to find the solution [closed]

    - by Tarun
    1. Which of the following advantages does System.Collections.IDictionaryEnumerator provide over System.Collections.IEnumerator? a. It adds properties for direct access to both the Key and the Value b. It is optimized to handle the structure of a Dictionary. c. It provides properties to determine if the Dictionary is enumerated in Key or Value order d. It provides reverse lookup methods to distinguish a Key from a specific Value 2. When Implementing System.EnterpriseServices.ServicedComponent derived classes, which of the following statements are true? a. Enabling object pooling requires an attribute on the class and the enabling of pooling in the COM+ catalog. b. Methods can be configured to automatically mark a transaction as complete by the use of attributes. c. You can configure authentication using the AuthenticationOption when the ActivationMode is set to Library. d. You can control the lifecycle policy of an individual instance using the SetLifetimeService method. 3. Which of the following are true regarding event declaration in the code below? class Sample { event MyEventHandlerType MyEvent; } a. MyEventHandlerType must be derived from System.EventHandler or System.EventHandler<TEventArgs> b. MyEventHandlerType must take two parameters, the first of the type Object, and the second of a class derived from System.EventArgs c. MyEventHandlerType may have a non-void return type d. If MyEventHandlerType is a generic type, event declaration must use a specialization of that type. e. MyEventHandlerType cannot be declared static 4. Which of the following statements apply to developing .NET code, using .NET utilities that are available with the SDK or Visual Studio? a. Developers can create assemblies directly from the MSIL Source Code. b. Developers can examine PE header information in an assembly. c. Developers can generate XML Schemas from class definitions contained within an assembly. d. Developers can strip all meta-data from managed assemblies. e. Developers can split an assembly into multiple assemblies. 5. Which of the following characteristics do classes in the System.Drawing namespace such as Brush,Font,Pen, and Icon share? a. They encapsulate native resource and must be properly Disposed to prevent potential exhausting of resources. b. They are all MarshalByRef derived classes, but functionality across AppDomains has specific limitations. c. You can inherit from these classes to provide enhanced or customized functionality 6. Which of the following are required to be true by objects which are going to be used as keys in a System.Collections.HashTable? a. They must handle case-sensitivity identically in both the GetHashCode() and Equals() methods. b. Key objects must be immutable for the duration they are used within a HashTable. c. Get HashCode() must be overridden to provide the same result, given the same parameters, regardless of reference equalityl unless the HashTable constructor is provided with an IEqualityComparer parameter. d. Each Element in a HashTable is stored as a Key/Value pair of the type System.Collections.DictionaryElement e. All of the above 7. Which of the following are true about Nullable types? a. A Nullable type is a reference type. b. A Nullable type is a structure. c. An implicit conversion exists from any non-nullable value type to a nullable form of that type. d. An implicit conversion exists from any nullable value type to a non-nullable form of that type. e. A predefined conversion from the nullable type S? to the nullable type T? exists if there is a predefined conversion from the non-nullable type S to the non-nullable type T 8. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is a private instance member with a leading underscore that can be programmatically referenced. c. The compiler generates a backing field that is accessible via reflection d. The compiler generates a code that will store the information separately from the instance to ensure its security. 9. Which of the following does using Initializer Syntax with a collection as shown below require? CollectionClass numbers = new CollectionClass { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; a. The Collection Class must implement System.Collections.Generic.ICollection<T> b. The Collection Class must implement System.Collections.Generic.IList<T> c. Each of the Items in the Initializer List will be passed to the Add<T>(T item) method d. The items in the initializer will be treated as an IEnumerable<T> and passed to the collection constructor+K110 10. What impact will using implicitly typed local variables as in the following example have? var sample = "Hello World"; a. The actual type is determined at compilation time, and has no impact on the runtime b. The actual type is determined at runtime, and late binding takes effect c. The actual type is based on the native VARIANT concept, and no binding to a specific type takes place. d. "var" itself is a specific type defined by the framework, and no special binding takes place 11. Which of the following is not supported by remoting object types? a. well-known singleton b. well-known single call c. client activated d. context-agile 12. In which of the following ways do structs differ from classes? a. Structs can not implement interfaces b. Structs cannot inherit from a base struct c. Structs cannot have events interfaces d. Structs cannot have virtual methods 13. Which of the following is not an unboxing conversion? a. void Sample1(object o) { int i = (int)o; } b. void Sample1(ValueType vt) { int i = (int)vt; } c. enum E { Hello, World} void Sample1(System.Enum et) { E e = (E) et; } d. interface I { int Value { get; set; } } void Sample1(I vt) { int i = vt.Value; } e. class C { public int Value { get; set; } } void Sample1(C vt) { int i = vt.Value; } 14. Which of the following are characteristics of the System.Threading.Timer class? a. The method provided by the TimerCallback delegate will always be invoked on the thread which created the timer. b. The thread which creates the timer must have a message processing loop (i.e. be considered a UI thread) c. The class contains protection to prevent reentrancy to the method provided by the TimerCallback delegate d. You can receive notification of an instance being Disposed by calling an overload of the Dispose method. 15. What is the proper declaration of a method which will handle the following event? Class MyClass { public event EventHandler MyEvent; } a. public void A_MyEvent(object sender, MyArgs e) { } b. public void A_MyEvent(object sender, EventArgs e) { } c. public void A_MyEvent(MyArgs e) { } d. public void A_MyEvent(MyClass sender,EventArgs e) { } 16. Which of the following scenarios are applicable to Window Workflow Foundation? a. Document-centric workflows b. Human workflows c. User-interface page flows d. Builtin support for communications across multiple applications and/or platforms e. All of the above 17. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is a private instance member with a leading underscore that can be programmatically referenced. c. The compiler generates a backing field that is accessible via reflection d. The compiler generates a code that will store the information separately from the instance to ensure its security. 18 While using the capabilities supplied by the System.Messaging classes, which of the following are true? a. Information must be explicitly converted to/from a byte stream before it uses the MessageQueue class b. Invoking the MessageQueue.Send member defaults to using the System.Messaging.XmlMessageFormatter to serialize the object. c. Objects must be XMLSerializable in order to be transferred over a MessageQueue instance. d. The first entry in a MessageQueue must be removed from the queue before the next entry can be accessed e. Entries removed from a MessageQueue within the scope of a transaction, will be pushed back into the front of the queue if the transaction fails. 19. Which of the following are true about declarative attributes? a. They must be inherited from the System.Attribute. b. Attributes are instantiated at the same time as instances of the class to which they are applied. c. Attribute classes may be restricted to be applied only to application element types. d. By default, a given attribute may be applied multiple times to the same application element. 20. When using version 3.5 of the framework in applications which emit a dynamic code, which of the following are true? a. A Partial trust code can not emit and execute a code b. A Partial trust application must have the SecurityCriticalAttribute attribute have called Assert ReflectionEmit permission c. The generated code no more permissions than the assembly which emitted it. d. It can be executed by calling System.Reflection.Emit.DynamicMethod( string name, Type returnType, Type[] parameterTypes ) without any special permissions Within Windows Workflow Foundation, Compensating Actions are used for: a. provide a means to rollback a failed transaction b. provide a means to undo a successfully committed transaction later c. provide a means to terminate an in process transaction d. achieve load balancing by adapting to the current activity 21. What is the proper declaration of a method which will handle the following event? Class MyClass { public event EventHandler MyEvent; } a. public void A_MyEvent(object sender, MyArgs e) { } b. public void A_MyEvent(object sender, EventArgs e) { } c. public void A_MyEvent(MyArgs e) { } d. public void A_MyEvent(MyClass sender,EventArgs e) { } 22. Which of the following controls allows the use of XSL to transform XML content into formatted content? a. System.Web.UI.WebControls.Xml b. System.Web.UI.WebControls.Xslt c. System.Web.UI.WebControls.Substitution d. System.Web.UI.WebControls.Transform 23. To which of the following do automatic properties refer? a. You declare (explicitly or implicitly) the accessibility of the property and get and set accessors, but do not provide any implementation or backing field b. You attribute a member field so that the compiler will generate get and set accessors c. The compiler creates properties for your class based on class level attributes d. They are properties which are automatically invoked as part of the object construction process 24. Which of the following are true about Nullable types? a. A Nullable type is a reference type. b. An implicit conversion exists from any non-nullable value type to a nullable form of that type. c. A predefined conversion from the nullable type S? to the nullable type T? exists if there is a predefined conversion from the non-nullable type S to the non-nullable type T 25. When using an automatic property, which of the following statements is true? a. The compiler generates a backing field that is completely inaccessible from the application code. b. The compiler generates a backing field that is accessible via reflection. c. The compiler generates a code that will store the information separately from the instance to ensure its security. 26. When using an implicitly typed array, which of the following is most appropriate? a. All elements in the initializer list must be of the same type. b. All elements in the initializer list must be implicitly convertible to a known type which is the actual type of at least one member in the initializer list c. All elements in the initializer list must be implicitly convertible to common type which is a base type of the items actually in the list 27. Which of the following is false about anonymous types? a. They can be derived from any reference type. b. Two anonymous types with the same named parameters in the same order declared in different classes have the same type. c. All properties of an anonymous type are read/write. 28. Which of the following are true about Extension methods. a. They can be declared either static or instance members b. They must be declared in the same assembly (but may be in different source files) c. Extension methods can be used to override existing instance methods d. Extension methods with the same signature for the same class may be declared in multiple namespaces without causing compilation errors

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  • Pure Server-Side Filtering with RadGridView and WCF RIA Services

    Those of you who are familiar with WCF RIA Services know that the DomainDataSource control provides a FilterDescriptors collection that enables you to filter data returned by the query on the server. We have been using this DomainDataSource feature in our RIA Services with DomainDataSource online example for almost an year now. In the example, we are listening for RadGridViews Filtering event in order to intercept any filtering that is performed on the client and translate it to something that the DomainDataSource will understand, in this case a System.Windows.Data.FilterDescriptor being added or removed from its FilterDescriptors collection. Think of RadGridView.FilterDescriptors as client-side filtering and of DomainDataSource.FilterDescriptors as server-side filtering. We no longer need the client-side one. With the introduction of the Custom Filtering Controls feature many new possibilities have opened. With these custom controls we no longer need to do any filtering on the client. I have prepared a very small project that demonstrates how to filter solely on the server by using a custom filtering control. As I have already mentioned filtering on the server is done through the FilterDescriptors collection of the DomainDataSource control. This collection holds instances of type System.Windows.Data.FilterDescriptor. The FilterDescriptor has three important properties: PropertyPath: Specifies the name of the property that we want to filter on (the left operand). Operator: Specifies the type of comparison to use when filtering. An instance of FilterOperator Enumeration. Value: The value to compare with (the right operand). An instance of the Parameter Class. By adding filters, you can specify that only entities which meet the condition in the filter are loaded from the domain context. In case you are not familiar with these concepts you might find Brad Abrams blog interesting. Now, our requirements are to create some kind of UI that will manipulate the DomainDataSource.FilterDescriptors collection. When it comes to collections, my first choice of course would be RadGridView. If you are not familiar with the Custom Filtering Controls concept I would strongly recommend getting acquainted with my step-by-step tutorial Custom Filtering with RadGridView for Silverlight and checking the online example out. I have created a simple custom filtering control that contains a RadGridView and several buttons. This control is aware of the DomainDataSource instance, since it is operating on its FilterDescriptors collection. In fact, the RadGridView that is inside it is bound to this collection. In order to display filters that are relevant for the current column only, I have applied a filter to the grid. This filter is a Telerik.Windows.Data.FilterDescriptor and is used to filter the little grid inside the custom control. It should not be confused with the DomainDataSource.FilterDescriptors collection that RadGridView is actually bound to. These are the RIA filters. Additionally, I have added several other features. For example, if you have specified a DataFormatString on your original column, the Value column inside the custom control will pick it up and format the filter values accordingly. Also, I have transferred the data type of the column that you are filtering to the Value column of the custom control. This will help the little RadGridView determine what kind of editor to show up when you begin edit, for example a date picker for DateTime columns. Finally, I have added four buttons two of them can be used to add or remove filters and the other two will communicate the changes you have made to the server. Here is the full source code of the DomainDataSourceFilteringControl. The XAML: <UserControl x:Class="PureServerSideFiltering.DomainDataSourceFilteringControl"    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     xmlns:telerikGrid="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView"     xmlns:telerik="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls"     Width="300">     <Border x:Name="LayoutRoot"             BorderThickness="1"             BorderBrush="#FF8A929E"             Padding="5"             Background="#FFDFE2E5">           <Grid>             <Grid.RowDefinitions>                 <RowDefinition Height="Auto"/>                 <RowDefinition Height="150"/>                 <RowDefinition Height="Auto"/>             </Grid.RowDefinitions>               <StackPanel Grid.Row="0"                         Margin="2"                         Orientation="Horizontal"                         HorizontalAlignment="Center">                 <telerik:RadButton Name="addFilterButton"                                   Click="OnAddFilterButtonClick"                                   Content="Add Filter"                                   Margin="2"                                   Width="96"/>                 <telerik:RadButton Name="removeFilterButton"                                   Click="OnRemoveFilterButtonClick"                                   Content="Remove Filter"                                   Margin="2"                                   Width="96"/>             </StackPanel>               <telerikGrid:RadGridView Name="filtersGrid"                                     Grid.Row="1"                                     Margin="2"                                     ItemsSource="{Binding FilterDescriptors}"                                     AddingNewDataItem="OnFilterGridAddingNewDataItem"                                     ColumnWidth="*"                                     ShowGroupPanel="False"                                     AutoGenerateColumns="False"                                     CanUserResizeColumns="False"                                     CanUserReorderColumns="False"                                     CanUserFreezeColumns="False"                                     RowIndicatorVisibility="Collapsed"                                     IsFilteringAllowed="False"                                     CanUserSortColumns="False">                 <telerikGrid:RadGridView.Columns>                     <telerikGrid:GridViewComboBoxColumn DataMemberBinding="{Binding Operator}"                                                         UniqueName="Operator"/>                     <telerikGrid:GridViewDataColumn Header="Value"                                                     DataMemberBinding="{Binding Value.Value}"                                                     UniqueName="Value"/>                 </telerikGrid:RadGridView.Columns>             </telerikGrid:RadGridView>               <StackPanel Grid.Row="2"                         Margin="2"                         Orientation="Horizontal"                         HorizontalAlignment="Center">                 <telerik:RadButton Name="filterButton"                                   Click="OnApplyFiltersButtonClick"                                   Content="Apply Filters"                                   Margin="2"                                   Width="96"/>                 <telerik:RadButton Name="clearButton"                                   Click="OnClearFiltersButtonClick"                                   Content="Clear Filters"                                   Margin="2"                                   Width="96"/>             </StackPanel>           </Grid>       </Border> </UserControl>   And the code-behind: 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 Telerik.Windows.Controls.GridView; using System.Windows.Data; using Telerik.Windows.Controls; using Telerik.Windows.Data;   namespace PureServerSideFiltering {     /// <summary>     /// A custom filtering control capable of filtering purely server-side.     /// </summary>     public partial class DomainDataSourceFilteringControl : UserControl, IFilteringControl     {         // The main player here.         DomainDataSource domainDataSource;           // This is the name of the property that this column displays.         private string dataMemberName;           // This is the type of the property that this column displays.         private Type dataMemberType;           /// <summary>         /// Identifies the <see cref="IsActive"/> dependency property.         /// </summary>         /// <remarks>         /// The state of the filtering funnel (i.e. full or empty) is bound to this property.         /// </remarks>         public static readonly DependencyProperty IsActiveProperty =             DependencyProperty.Register(                 "IsActive",                 typeof(bool),                 typeof(DomainDataSourceFilteringControl),                 new PropertyMetadata(false));           /// <summary>         /// Gets or sets a value indicating whether the filtering is active.         /// </summary>         /// <remarks>         /// Set this to true if you want to lit-up the filtering funnel.         /// </remarks>         public bool IsActive         {             get { return (bool)GetValue(IsActiveProperty); }             set { SetValue(IsActiveProperty, value); }         }           /// <summary>         /// Gets or sets the domain data source.         /// We need this in order to work on its FilterDescriptors collection.         /// </summary>         /// <value>The domain data source.</value>         public DomainDataSource DomainDataSource         {             get { return this.domainDataSource; }             set { this.domainDataSource = value; }         }           public System.Windows.Data.FilterDescriptorCollection FilterDescriptors         {             get { return this.DomainDataSource.FilterDescriptors; }         }           public DomainDataSourceFilteringControl()         {             InitializeComponent();         }           public void Prepare(GridViewBoundColumnBase column)         {             this.LayoutRoot.DataContext = this;               if (this.DomainDataSource == null)             {                 // Sorry, but we need a DomainDataSource. Can't do anything without it.                 return;             }               // This is the name of the property that this column displays.             this.dataMemberName = column.GetDataMemberName();               // This is the type of the property that this column displays.             // We need this in order to see which FilterOperators to feed to the combo-box column.             this.dataMemberType = column.DataType;               // We will use our magic Type extension method to see which operators are applicable for             // this data type. You can go to the extension method body and see what it does.             ((GridViewComboBoxColumn)this.filtersGrid.Columns["Operator"]).ItemsSource                 = this.dataMemberType.ApplicableFilterOperators();               // This is very nice as well. We will tell the Value column its data type. In this way             // RadGridView will pick up the best editor according to the data type. For example,             // if the data type of the value is DateTime, you will be editing it with a DatePicker.             // Nice!             ((GridViewDataColumn)this.filtersGrid.Columns["Value"]).DataType = this.dataMemberType;               // Yet another nice feature. We will transfer the original DataFormatString (if any) to             // the Value column. In this way if you have specified a DataFormatString for the original             // column, you will see all filter values formatted accordingly.             ((GridViewDataColumn)this.filtersGrid.Columns["Value"]).DataFormatString = column.DataFormatString;               // This is important. Since our little filtersGrid will be bound to the entire collection             // of this.domainDataSource.FilterDescriptors, we need to set a Telerik filter on the             // grid so that it will display FilterDescriptor which are relevane to this column ONLY!             Telerik.Windows.Data.FilterDescriptor columnFilter = new Telerik.Windows.Data.FilterDescriptor("PropertyPath"                 , Telerik.Windows.Data.FilterOperator.IsEqualTo                 , this.dataMemberName);             this.filtersGrid.FilterDescriptors.Add(columnFilter);               // We want to listen for this in order to activate and de-activate the UI funnel.             this.filtersGrid.Items.CollectionChanged += this.OnFilterGridItemsCollectionChanged;         }           /// <summary>         // Since the DomainDataSource is a little bit picky about adding uninitialized FilterDescriptors         // to its collection, we will prepare each new instance with some default values and then         // the user can change them later. Go to the event handler to see how we do this.         /// </summary>         void OnFilterGridAddingNewDataItem(object sender, GridViewAddingNewEventArgs e)         {             // We need to initialize the new instance with some values and let the user go on from here.             System.Windows.Data.FilterDescriptor newFilter = new System.Windows.Data.FilterDescriptor();               // This is a must. It should know what member it is filtering on.             newFilter.PropertyPath = this.dataMemberName;               // Initialize it with one of the allowed operators.             // TypeExtensions.ApplicableFilterOperators method for more info.             newFilter.Operator = this.dataMemberType.ApplicableFilterOperators().First();               if (this.dataMemberType == typeof(DateTime))             {                 newFilter.Value.Value = DateTime.Now;             }             else if (this.dataMemberType == typeof(string))             {                 newFilter.Value.Value = "<enter text>";             }             else if (this.dataMemberType.IsValueType)             {                 // We need something non-null for all value types.                 newFilter.Value.Value = Activator.CreateInstance(this.dataMemberType);             }               // Let the user edit the new filter any way he/she likes.             e.NewObject = newFilter;         }           void OnFilterGridItemsCollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)         {             // We are active only if we have any filters define. In this case the filtering funnel will lit-up.             this.IsActive = this.filtersGrid.Items.Count > 0;         }           private void OnApplyFiltersButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // Comment this if you want the popup to stay open after the button is clicked.             this.ClosePopup();               // Since this.domainDataSource.AutoLoad is false, this will take into             // account all filtering changes that the user has made since the last             // Load() and pull the new data to the client.             this.DomainDataSource.Load();         }           private void OnClearFiltersButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // We want to remove ONLY those filters from the DomainDataSource             // that this control is responsible for.             this.DomainDataSource.FilterDescriptors                 .Where(fd => fd.PropertyPath == this.dataMemberName) // Only "our" filters.                 .ToList()                 .ForEach(fd => this.DomainDataSource.FilterDescriptors.Remove(fd)); // Bye-bye!               // Comment this if you want the popup to stay open after the button is clicked.             this.ClosePopup();               // After we did our housekeeping, get the new data to the client.             this.DomainDataSource.Load();         }           private void OnAddFilterButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // Let the user enter his/or her requirements for a new filter.             this.filtersGrid.BeginInsert();             this.filtersGrid.UpdateLayout();         }           private void OnRemoveFilterButtonClick(object sender, RoutedEventArgs e)         {             if (this.DomainDataSource.IsLoadingData)             {                 return;             }               // Find the currently selected filter and destroy it.             System.Windows.Data.FilterDescriptor filterToRemove = this.filtersGrid.SelectedItem as System.Windows.Data.FilterDescriptor;             if (filterToRemove != null                 && this.DomainDataSource.FilterDescriptors.Contains(filterToRemove))             {                 this.DomainDataSource.FilterDescriptors.Remove(filterToRemove);             }         }           private void ClosePopup()         {             System.Windows.Controls.Primitives.Popup popup = this.ParentOfType<System.Windows.Controls.Primitives.Popup>();             if (popup != null)             {                 popup.IsOpen = false;             }         }     } }   Finally, we need to tell RadGridViews Columns to use this custom control instead of the default one. Here is how to do it: 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.Data; using Telerik.Windows.Data; using Telerik.Windows.Controls; using Telerik.Windows.Controls.GridView;   namespace PureServerSideFiltering {     public partial class MainPage : UserControl     {         public MainPage()         {             InitializeComponent();             this.grid.AutoGeneratingColumn += this.OnGridAutoGeneratingColumn;               // Uncomment this if you want the DomainDataSource to start pre-filtered.             // You will notice how our custom filtering controls will correctly read this information,             // populate their UI with the respective filters and lit-up the funnel to indicate that             // filtering is active. Go ahead and try it.             this.employeesDataSource.FilterDescriptors.Add(new System.Windows.Data.FilterDescriptor("Title", System.Windows.Data.FilterOperator.Contains, "Assistant"));             this.employeesDataSource.FilterDescriptors.Add(new System.Windows.Data.FilterDescriptor("HireDate", System.Windows.Data.FilterOperator.IsGreaterThan, new DateTime(1998, 12, 31)));             this.employeesDataSource.FilterDescriptors.Add(new System.Windows.Data.FilterDescriptor("HireDate", System.Windows.Data.FilterOperator.IsLessThanOrEqualTo, new DateTime(1999, 12, 31)));               this.employeesDataSource.Load();         }           /// <summary>         /// First of all, we will need to replace the default filtering control         /// of each column with out custom filtering control DomainDataSourceFilteringControl         /// </summary>         private void OnGridAutoGeneratingColumn(object sender, GridViewAutoGeneratingColumnEventArgs e)         {             GridViewBoundColumnBase dataColumn = e.Column as GridViewBoundColumnBase;             if (dataColumn != null)             {                 // We do not like ugly dates.                 if (dataColumn.DataType == typeof(DateTime))                 {                     dataColumn.DataFormatString = "{0:d}"; // Short date pattern.                       // Notice how this format will be later transferred to the Value column                     // of the grid that we have inside the DomainDataSourceFilteringControl.                 }                   // Replace the default filtering control with our.                 dataColumn.FilteringControl = new DomainDataSourceFilteringControl()                 {                     // Let the control know about the DDS, after all it will work directly on it.                     DomainDataSource = this.employeesDataSource                 };                   // Finally, lit-up the filtering funnel through the IsActive dependency property                 // in case there are some filters on the DDS that match our column member.                 string dataMemberName = dataColumn.GetDataMemberName();                 dataColumn.FilteringControl.IsActive =                     this.employeesDataSource.FilterDescriptors                     .Where(fd => fd.PropertyPath == dataMemberName)                     .Count() > 0;             }         }     } } The best part is that we are not only writing filters for the DomainDataSource we can read and load them. If the DomainDataSource has some pre-existing filters (like I have created in the code above), our control will read them and will populate its UI accordingly. Even the filtering funnel will light-up! Remember, the funnel is controlled by the IsActive property of our control. While this is just a basic implementation, the source code is absolutely yours and you can take it from here and extend it to match your specific business requirements. Below the main grid there is another debug grid. With its help you can monitor what filter descriptors are added and removed to the domain data source. Download Source Code. (You will have to have the AdventureWorks sample database installed on the default SQLExpress instance in order to run it.) Enjoy!Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Sensible Way to Pass Web Data in XML to a SQL Server Database

    - by Emtucifor
    After exploring several different ways to pass web data to a database for update purposes, I'm wondering if XML might be a good strategy. The database is currently SQL 2000. In a few months it will move to SQL 2005 and I will be able to change things if needed, but I need a SQL 2000 solution now. First of all, the database in question uses the EAV model. I know that this kind of database is generally highly frowned on, so for the purposes of this question, please just accept that this is not going to change. The current update method has the web server inserting values (that have all been converted first to their correct underlying types, then to sql_variant) to a temp table. A stored procedure is then run which expects the temp table to exist and it takes care of updating, inserting, or deleting things as needed. So far, only a single element has needed to be updated at a time. But now, there is a requirement to be able to edit multiple elements at once, and also to support hierarchical elements, each of which can have its own list of attributes. Here's some example XML I hand-typed to demonstrate what I'm thinking of. Note that in this database the Entity is Element and an ID of 0 signifies "create" aka an insert of a new item. <Elements> <Element ID="1234"> <Attr ID="221">Value</Attr> <Attr ID="225">287</Attr> <Attr ID="234"> <Element ID="99825"> <Attr ID="7">Value1</Attr> <Attr ID="8">Value2</Attr> <Attr ID="9" Action="delete" /> </Element> <Element ID="99826" Action="delete" /> <Element ID="0" Type="24"> <Attr ID="7">Value4</Attr> <Attr ID="8">Value5</Attr> <Attr ID="9">Value6</Attr> </Element> <Element ID="0" Type="24"> <Attr ID="7">Value7</Attr> <Attr ID="8">Value8</Attr> <Attr ID="9">Value9</Attr> </Element> </Attr> <Rel ID="3827" Action="delete" /> <Rel ID="2284" Role="parent"> <Element ID="3827" /> <Element ID="3829" /> <Attr ID="665">1</Attr> </Rel> <Rel ID="0" Type="23" Role="child"> <Element ID="3830" /> <Attr ID="67" </Rel> </Element> <Element ID="0" Type="87"> <Attr ID="221">Value</Attr> <Attr ID="225">569</Attr> <Attr ID="234"> <Element ID="0" Type="24"> <Attr ID="7">Value10</Attr> <Attr ID="8">Value11</Attr> <Attr ID="9">Value12</Attr> </Element> </Attr> </Element> <Element ID="1235" Action="delete" /> </Elements> Some Attributes are straight value types, such as AttrID 221. But AttrID 234 is a special "multi-value" type that can have a list of elements underneath it, and each one can have one or more values. Types only need to be presented when a new item is created, since the ElementID fully implies the type if it already exists. I'll probably support only passing in changed items (as detected by javascript). And there may be an Action="Delete" on Attr elements as well, since NULLs are treated as "unselected"--sometimes it's very important to know if a Yes/No question has intentionally been answered No or if no one's bothered to say Yes yet. There is also a different kind of data, a Relationship. At this time, those are updated through individual AJAX calls as things are edited in the UI, but I'd like to include those so that changes to relationships can be canceled (right now, once you change it, it's done). So those are really elements, too, but they are called Rel instead of Element. Relationships are implemented as ElementID1 and ElementID2, so the RelID 2284 in the XML above is in the database as: ElementID 2284 ElementID1 1234 ElementID2 3827 Having multiple children in one relationship isn't currently supported, but it would be nice later. Does this strategy and the example XML make sense? Is there a more sensible way? I'm just looking for some broad critique to help save me from going down a bad path. Any aspect that you'd like to comment on would be helpful. The web language happens to be Classic ASP, but that could change to ASP.Net at some point. A persistence engine like Linq or nHibernate is probably not acceptable right now--I just want to get this already working application enhanced without a huge amount of development time. I'll choose the answer that shows experience and has a balance of good warnings about what not to do, confirmations of what I'm planning to do, and recommendations about something else to do. I'll make it as objective as possible. P.S. I'd like to handle unicode characters as well as very long strings (10k +). UPDATE I have had this working for some time and I used the ADO Recordset Save-To-Stream trick to make creating the XML really easy. The result seems to be fairly fast, though if speed ever becomes a problem I may revisit this. In the meantime, my code works to handle any number of elements and attributes on the page at once, including updating, deleting, and creating new items all in one go. I settled on a scheme like so for all my elements: Existing data elements Example: input name e12345_a678 (element 12345, attribute 678), the input value is the value of the attribute. New elements Javascript copies a hidden template of the set of HTML elements needed for the type into the correct location on the page, increments a counter to get a new ID for this item, and prepends the number to the names of the form items. var newid = 0; function metadataAdd(reference, nameid, value) { var t = document.createElement('input'); t.setAttribute('name', nameid); t.setAttribute('id', nameid); t.setAttribute('type', 'hidden'); t.setAttribute('value', value); reference.appendChild(t); } function multiAdd(target, parentelementid, attrid, elementtypeid) { var proto = document.getElementById('a' + attrid + '_proto'); var instance = document.createElement('p'); target.parentNode.parentNode.insertBefore(instance, target.parentNode); var thisid = ++newid; instance.innerHTML = proto.innerHTML.replace(/{prefix}/g, 'n' + thisid + '_'); instance.id = 'n' + thisid; instance.className += ' new'; metadataAdd(instance, 'n' + thisid + '_p', parentelementid); metadataAdd(instance, 'n' + thisid + '_c', attrid); metadataAdd(instance, 'n' + thisid + '_t', elementtypeid); return false; } Example: Template input name _a678 becomes n1_a678 (a new element, the first one on the page, attribute 678). all attributes of this new element are tagged with the same prefix of n1. The next new item will be n2, and so on. Some hidden form inputs are created: n1_t, value is the elementtype of the element to be created n1_p, value is the parent id of the element (if it is a relationship) n1_c, value is the child id of the element (if it is a relationship) Deleting elements A hidden input is created in the form e12345_t with value set to 0. The existing controls displaying that attribute's values are disabled so they are not included in the form post. So "set type to 0" is treated as delete. With this scheme, every item on the page has a unique name and can be distinguished properly, and every action can be represented properly. When the form is posted, here's a sample of building one of the two recordsets used (classic ASP code): Set Data = Server.CreateObject("ADODB.Recordset") Data.Fields.Append "ElementID", adInteger, 4, adFldKeyColumn Data.Fields.Append "AttrID", adInteger, 4, adFldKeyColumn Data.Fields.Append "Value", adLongVarWChar, 2147483647, adFldIsNullable Or adFldMayBeNull Data.CursorLocation = adUseClient Data.CursorType = adOpenDynamic Data.Open This is the recordset for values, the other is for the elements themselves. I step through the posted form and for the element recordset use a Scripting.Dictionary populated with instances of a custom Class that has the properties I need, so that I can add the values piecemeal, since they don't always come in order. New elements are added as negative to distinguish them from regular elements (rather than requiring a separate column to indicate if it is new or addresses an existing element). I use regular expression to tear apart the form keys: "^(e|n)([0-9]{1,10})_(a|p|t|c)([0-9]{0,10})$" Then, adding an attribute looks like this. Data.AddNew ElementID.Value = DataID AttrID.Value = Integerize(Matches(0).SubMatches(3)) AttrValue.Value = Request.Form(Key) Data.Update ElementID, AttrID, and AttrValue are references to the fields of the recordset. This method is hugely faster than using Data.Fields("ElementID").Value each time. I loop through the Dictionary of element updates and ignore any that don't have all the proper information, adding the good ones to the recordset. Then I call my data-updating stored procedure like so: Set Cmd = Server.CreateObject("ADODB.Command") With Cmd Set .ActiveConnection = MyDBConn .CommandType = adCmdStoredProc .CommandText = "DataPost" .Prepared = False .Parameters.Append .CreateParameter("@ElementMetadata", adLongVarWChar, adParamInput, 2147483647, XMLFromRecordset(Element)) .Parameters.Append .CreateParameter("@ElementData", adLongVarWChar, adParamInput, 2147483647, XMLFromRecordset(Data)) End With Result.Open Cmd ' previously created recordset object with options set Here's the function that does the xml conversion: Private Function XMLFromRecordset(Recordset) Dim Stream Set Stream = Server.CreateObject("ADODB.Stream") Stream.Open Recordset.Save Stream, adPersistXML Stream.Position = 0 XMLFromRecordset = Stream.ReadText End Function Just in case the web page needs to know, the SP returns a recordset of any new elements, showing their page value and their created value (so I can see that n1 is now e12346 for example). Here are some key snippets from the stored procedure. Note this is SQL 2000 for now, though I'll be able to switch to 2005 soon: CREATE PROCEDURE [dbo].[DataPost] @ElementMetaData ntext, @ElementData ntext AS DECLARE @hdoc int --- snip --- EXEC sp_xml_preparedocument @hdoc OUTPUT, @ElementMetaData, '<xml xmlns:s="uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:rs="urn:schemas-microsoft-com:rowset" xmlns:z="#RowsetSchema" />' INSERT #ElementMetadata (ElementID, ElementTypeID, ElementID1, ElementID2) SELECT * FROM OPENXML(@hdoc, '/xml/rs:data/rs:insert/z:row', 0) WITH ( ElementID int, ElementTypeID int, ElementID1 int, ElementID2 int ) ORDER BY ElementID -- orders negative items (new elements) first so they begin counting at 1 for later ID calculation EXEC sp_xml_removedocument @hdoc --- snip --- UPDATE E SET E.ElementTypeID = M.ElementTypeID FROM Element E INNER JOIN #ElementMetadata M ON E.ElementID = M.ElementID WHERE E.ElementID >= 1 AND M.ElementTypeID >= 1 The following query does the correlation of the negative new element ids to the newly inserted ones: UPDATE #ElementMetadata -- Correlate the new ElementIDs with the input rows SET NewElementID = Scope_Identity() - @@RowCount + DataID WHERE ElementID < 0 Other set-based queries do all the other work of validating that the attributes are allowed, are the correct data type, and inserting, updating, and deleting elements and attributes. I hope this brief run-down is useful to others some day! Converting ADO Recordsets to an XML stream was a huge winner for me as it saved all sorts of time and had a namespace and schema already defined that made the results come out correctly. Using a flatter XML format with 2 inputs was also much easier than sticking to some ideal about having everything in a single XML stream.

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  • Sensible Way to Pass Web Data to Sql Server Database

    - by Emtucifor
    After exploring several different ways to pass web data to a database for update purposes, I'm wondering if XML might be a good strategy. The database is currently SQL 2000. In a few months it will move to SQL 2005 and I will be able to change things if needed, but I need a SQL 2000 solution now. First of all, the database in question uses the EAV model. I know that this kind of database is generally highly frowned on, so for the purposes of this question, please just accept that this is not going to change. The current update method has the web server inserting values (that have all been converted first to their correct underlying types, then to sql_variant) to a temp table. A stored procedure is then run which expects the temp table to exist and it takes care of updating, inserting, or deleting things as needed. So far, only a single element has needed to be updated at a time. But now, there is a requirement to be able to edit multiple elements at once, and also to support hierarchical elements, each of which can have its own list of attributes. Here's some example XML I hand-typed to demonstrate what I'm thinking of. Note that in this database the Entity is Element and an ID of 0 signifies "create" aka an insert of a new item. <Elements> <Element ID="1234"> <Attr ID="221">Value</Attr> <Attr ID="225">287</Attr> <Attr ID="234"> <Element ID="99825"> <Attr ID="7">Value1</Attr> <Attr ID="8">Value2</Attr> <Attr ID="9" Action="delete" /> </Element> <Element ID="99826" Action="delete" /> <Element ID="0" Type="24"> <Attr ID="7">Value4</Attr> <Attr ID="8">Value5</Attr> <Attr ID="9">Value6</Attr> </Element> <Element ID="0" Type="24"> <Attr ID="7">Value7</Attr> <Attr ID="8">Value8</Attr> <Attr ID="9">Value9</Attr> </Element> </Attr> <Rel ID="3827" Action="delete" /> <Rel ID="2284" Role="parent"> <Element ID="3827" /> <Element ID="3829" /> <Attr ID="665">1</Attr> </Rel> <Rel ID="0" Type="23" Role="child"> <Element ID="3830" /> <Attr ID="67" </Rel> </Element> <Element ID="0" Type="87"> <Attr ID="221">Value</Attr> <Attr ID="225">569</Attr> <Attr ID="234"> <Element ID="0" Type="24"> <Attr ID="7">Value10</Attr> <Attr ID="8">Value11</Attr> <Attr ID="9">Value12</Attr> </Element> </Attr> </Element> <Element ID="1235" Action="delete" /> </Elements> Some Attributes are straight value types, such as AttrID 221. But AttrID 234 is a special "multi-value" type that can have a list of elements underneath it, and each one can have one or more values. Types only need to be presented when a new item is created, since the ElementID fully implies the type if it already exists. I'll probably support only passing in changed items (as detected by javascript). And there may be an Action="Delete" on Attr elements as well, since NULLs are treated as "unselected"--sometimes it's very important to know if a Yes/No question has intentionally been answered No or if no one's bothered to say Yes yet. There is also a different kind of data, a Relationship. At this time, those are updated through individual AJAX calls as things are edited in the UI, but I'd like to include those so that changes to relationships can be canceled (right now, once you change it, it's done). So those are really elements, too, but they are called Rel instead of Element. Relationships are implemented as ElementID1 and ElementID2, so the RelID 2284 in the XML above is in the database as: ElementID 2284 ElementID1 1234 ElementID2 3827 Having multiple children in one relationship isn't currently supported, but it would be nice later. Does this strategy and the example XML make sense? Is there a more sensible way? I'm just looking for some broad critique to help save me from going down a bad path. Any aspect that you'd like to comment on would be helpful. The web language happens to be Classic ASP, but that could change to ASP.Net at some point. A persistence engine like Linq or nHibernate is probably not acceptable right now--I just want to get this already working application enhanced without a huge amount of development time. I'll choose the answer that shows experience and has a balance of good warnings about what not to do, confirmations of what I'm planning to do, and recommendations about something else to do. I'll make it as objective as possible. P.S. I'd like to handle unicode characters as well as very long strings (10k +). UPDATE I have had this working for some time and I used the ADO Recordset Save-To-Stream trick to make creating the XML really easy. The result seems to be fairly fast, though if speed ever becomes a problem I may revisit this. In the meantime, my code works to handle any number of elements and attributes on the page at once, including updating, deleting, and creating new items all in one go. I settled on a scheme like so for all my elements: Existing data elements Example: input name e12345_a678 (element 12345, attribute 678), the input value is the value of the attribute. New elements Javascript copies a hidden template of the set of HTML elements needed for the type into the correct location on the page, increments a counter to get a new ID for this item, and prepends the number to the names of the form items. var newid = 0; function metadataAdd(reference, nameid, value) { var t = document.createElement('input'); t.setAttribute('name', nameid); t.setAttribute('id', nameid); t.setAttribute('type', 'hidden'); t.setAttribute('value', value); reference.appendChild(t); } function multiAdd(target, parentelementid, attrid, elementtypeid) { var proto = document.getElementById('a' + attrid + '_proto'); var instance = document.createElement('p'); target.parentNode.parentNode.insertBefore(instance, target.parentNode); var thisid = ++newid; instance.innerHTML = proto.innerHTML.replace(/{prefix}/g, 'n' + thisid + '_'); instance.id = 'n' + thisid; instance.className += ' new'; metadataAdd(instance, 'n' + thisid + '_p', parentelementid); metadataAdd(instance, 'n' + thisid + '_c', attrid); metadataAdd(instance, 'n' + thisid + '_t', elementtypeid); return false; } Example: Template input name _a678 becomes n1_a678 (a new element, the first one on the page, attribute 678). all attributes of this new element are tagged with the same prefix of n1. The next new item will be n2, and so on. Some hidden form inputs are created: n1_t, value is the elementtype of the element to be created n1_p, value is the parent id of the element (if it is a relationship) n1_c, value is the child id of the element (if it is a relationship) Deleting elements A hidden input is created in the form e12345_t with value set to 0. The existing controls displaying that attribute's values are disabled so they are not included in the form post. So "set type to 0" is treated as delete. With this scheme, every item on the page has a unique name and can be distinguished properly, and every action can be represented properly. When the form is posted, here's a sample of building one of the two recordsets used (classic ASP code): Set Data = Server.CreateObject("ADODB.Recordset") Data.Fields.Append "ElementID", adInteger, 4, adFldKeyColumn Data.Fields.Append "AttrID", adInteger, 4, adFldKeyColumn Data.Fields.Append "Value", adLongVarWChar, 2147483647, adFldIsNullable Or adFldMayBeNull Data.CursorLocation = adUseClient Data.CursorType = adOpenDynamic Data.Open This is the recordset for values, the other is for the elements themselves. I step through the posted form and for the element recordset use a Scripting.Dictionary populated with instances of a custom Class that has the properties I need, so that I can add the values piecemeal, since they don't always come in order. New elements are added as negative to distinguish them from regular elements (rather than requiring a separate column to indicate if it is new or addresses an existing element). I use regular expression to tear apart the form keys: "^(e|n)([0-9]{1,10})_(a|p|t|c)([0-9]{0,10})$" Then, adding an attribute looks like this. Data.AddNew ElementID.Value = DataID AttrID.Value = Integerize(Matches(0).SubMatches(3)) AttrValue.Value = Request.Form(Key) Data.Update ElementID, AttrID, and AttrValue are references to the fields of the recordset. This method is hugely faster than using Data.Fields("ElementID").Value each time. I loop through the Dictionary of element updates and ignore any that don't have all the proper information, adding the good ones to the recordset. Then I call my data-updating stored procedure like so: Set Cmd = Server.CreateObject("ADODB.Command") With Cmd Set .ActiveConnection = MyDBConn .CommandType = adCmdStoredProc .CommandText = "DataPost" .Prepared = False .Parameters.Append .CreateParameter("@ElementMetadata", adLongVarWChar, adParamInput, 2147483647, XMLFromRecordset(Element)) .Parameters.Append .CreateParameter("@ElementData", adLongVarWChar, adParamInput, 2147483647, XMLFromRecordset(Data)) End With Result.Open Cmd ' previously created recordset object with options set Here's the function that does the xml conversion: Private Function XMLFromRecordset(Recordset) Dim Stream Set Stream = Server.CreateObject("ADODB.Stream") Stream.Open Recordset.Save Stream, adPersistXML Stream.Position = 0 XMLFromRecordset = Stream.ReadText End Function Just in case the web page needs to know, the SP returns a recordset of any new elements, showing their page value and their created value (so I can see that n1 is now e12346 for example). Here are some key snippets from the stored procedure. Note this is SQL 2000 for now, though I'll be able to switch to 2005 soon: CREATE PROCEDURE [dbo].[DataPost] @ElementMetaData ntext, @ElementData ntext AS DECLARE @hdoc int --- snip --- EXEC sp_xml_preparedocument @hdoc OUTPUT, @ElementMetaData, '<xml xmlns:s="uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882" xmlns:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" xmlns:rs="urn:schemas-microsoft-com:rowset" xmlns:z="#RowsetSchema" />' INSERT #ElementMetadata (ElementID, ElementTypeID, ElementID1, ElementID2) SELECT * FROM OPENXML(@hdoc, '/xml/rs:data/rs:insert/z:row', 0) WITH ( ElementID int, ElementTypeID int, ElementID1 int, ElementID2 int ) ORDER BY ElementID -- orders negative items (new elements) first so they begin counting at 1 for later ID calculation EXEC sp_xml_removedocument @hdoc --- snip --- UPDATE E SET E.ElementTypeID = M.ElementTypeID FROM Element E INNER JOIN #ElementMetadata M ON E.ElementID = M.ElementID WHERE E.ElementID >= 1 AND M.ElementTypeID >= 1 The following query does the correlation of the negative new element ids to the newly inserted ones: UPDATE #ElementMetadata -- Correlate the new ElementIDs with the input rows SET NewElementID = Scope_Identity() - @@RowCount + DataID WHERE ElementID < 0 Other set-based queries do all the other work of validating that the attributes are allowed, are the correct data type, and inserting, updating, and deleting elements and attributes. I hope this brief run-down is useful to others some day! Converting ADO Recordsets to an XML stream was a huge winner for me as it saved all sorts of time and had a namespace and schema already defined that made the results come out correctly. Using a flatter XML format with 2 inputs was also much easier than sticking to some ideal about having everything in a single XML stream.

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