ControlFilterExpression Class

Modifies a database query by using the data key of the item that is selected in a data-bound control.

Namespace:  System.Web.DynamicData
Assembly:  System.Web.DynamicData (in System.Web.DynamicData.dll)

public class ControlFilterExpression : DataSourceExpression

The ControlFilterExpression type exposes the following members.

  NameDescription
Public methodControlFilterExpressionInitializes a new instance of the ControlFilterExpression class.
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  NameDescription
Public propertyColumnGets or sets the name of the column that the query is based on.
Protected propertyContextGets the HttpContext instance of the owner control. (Inherited from DataSourceExpression.)
Public propertyControlIDGets or sets the ID of the source data-bound control.
Public propertyDataSourceGets the data source object that is associated with the owner control. (Inherited from DataSourceExpression.)
Protected propertyIsTrackingViewStateGets a value that indicates whether a data source expression object is tracking its view state changes. (Inherited from DataSourceExpression.)
Protected propertyOwnerGets the owner control. (Inherited from DataSourceExpression.)
Protected propertyViewStateGets an instance of the StateBag class that contains the current view state information. (Inherited from DataSourceExpression.)
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  NameDescription
Public methodEquals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetQueryableGets the data source query to modify. (Overrides DataSourceExpression.GetQueryable(IQueryable).)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodLoadViewStateRestores the previously saved view state. (Overrides DataSourceExpression.LoadViewState(Object).)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodSaveViewStateSaves the changes to view state since the time the page was posted to the server. (Overrides DataSourceExpression.SaveViewState().)
Public methodSetContextInitializes the filter expression with data source information. (Overrides DataSourceExpression.SetContext(Control, HttpContext, IQueryableDataSource).)
Public methodSetDirtyMarks the DataSourceExpression object so that its state will be saved in view state. (Inherited from DataSourceExpression.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Protected methodTrackViewStateCauses the ControlFilterExpression object to track changes to its view state so they can be stored in the control's view state object and to be persisted across requests for the same page. (Overrides DataSourceExpression.TrackViewState().)
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  NameDescription
Explicit interface implemetationPrivate propertyIStateManager.IsTrackingViewStateWhen implemented by a class, gets a value that indicates whether a data source expression object is tracking its view state changes. (Inherited from DataSourceExpression.)
Explicit interface implemetationPrivate methodIStateManager.LoadViewStateWhen implemented by a class, loads the previously saved view state of the data source expression object. (Inherited from DataSourceExpression.)
Explicit interface implemetationPrivate methodIStateManager.SaveViewStateWhen implemented by a class, saves the current view state of the DataSourceExpression object. (Inherited from DataSourceExpression.)
Explicit interface implemetationPrivate methodIStateManager.TrackViewStateWhen implemented by a class, tracks view state changes of the DataSourceExpression object so that the changes can be stored in the StateBag object for the data source expression object. (Inherited from DataSourceExpression.)
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The ControlFilterExpression class that is designed to be used when a page contains two data-bound controls such as a GridView control and a ListView control. One control is the source, where a data key (row) is selected. The other control is the target where the data is displayed based on the selected data key. The target data is obtained by a data source control that executes the query that is defined in the QueryExtender class and that is built by using the selected data key.

To use the ControlFilterExpression class in a page, you follow these steps:

  • Add the QueryExtender control to the page.

  • Set the TargetControlID property of the QueryExtender control to the ID of the target data source control.

  • Add a ControlFilterExpression instance to the QueryExtender control.

  • Set the ControlID property of the ControlFilterExpression element to the source data-bound control.

The following example shows how to use the ControlFilterExpression class to reference a source data-bound control, where the data key is selected. The QueryExtender control points to a target data source control that obtains data that is filtered by using the selected data key. In the example, the source data-bound control references a parent table and the target data-bound control references a child table.

<asp:QueryExtender ID="QueryExtenderID" 
    TargetControlID="TargetDataSourceID" runat="server">
    <asp:ControlFilterExpression ControlID="SourceGridViewID" />
</asp:QueryExtender>

.NET Framework

Supported in: 4

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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