DynamicFilterExpression Class
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DynamicFilterExpression Class

.NET Framework (current version)
 

Modifies a database query by using a value from specified filter control.

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

System.Object
  System.Web.UI.WebControls.Expressions.DataSourceExpression
    System.Web.DynamicData.DynamicFilterExpression

public class DynamicFilterExpression : DataSourceExpression

NameDescription
System_CAPS_pubmethodDynamicFilterExpression()

Initializes a new instance of the DynamicFilterExpression class.

NameDescription
System_CAPS_protpropertyContext

Gets the HttpContext instance of the owner control.(Inherited from DataSourceExpression.)

System_CAPS_pubpropertyControlID

Gets or sets the filter control identifier.

System_CAPS_pubpropertyDataSource

Gets the data source object that is associated with the owner control.(Inherited from DataSourceExpression.)

System_CAPS_protpropertyIsTrackingViewState

Gets a value that indicates whether a data source expression object is tracking its view state changes.(Inherited from DataSourceExpression.)

System_CAPS_protpropertyOwner

Gets the owner control.(Inherited from DataSourceExpression.)

System_CAPS_protpropertyViewState

Gets an instance of the StateBag class that contains the current view state information.(Inherited from DataSourceExpression.)

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetQueryable(IQueryable)

Gets the modified query using the current filter value.(Overrides DataSourceExpression.GetQueryable(IQueryable).)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_protmethodLoadViewState(Object)

Loads the state of the values in the DataSourceExpression object that must be persisted.(Inherited from DataSourceExpression.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_protmethodSaveViewState()

Saves the current view state of the DataSourceExpression object.(Inherited from DataSourceExpression.)

System_CAPS_pubmethodSetContext(Control, HttpContext, IQueryableDataSource)

Initializes the expression with data source information.(Overrides DataSourceExpression.SetContext(Control, HttpContext, IQueryableDataSource).)

System_CAPS_pubmethodSetDirty()

Marks the DataSourceExpression object so that its state will be saved in view state.(Inherited from DataSourceExpression.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_protmethodTrackViewState()

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.)

NameDescription
System_CAPS_pubinterfaceSystem_CAPS_privmethodIStateManager.LoadViewState(Object)

When implemented by a class, loads the previously saved view state of the data source expression object.(Inherited from DataSourceExpression.)

System_CAPS_pubinterfaceSystem_CAPS_privmethodIStateManager.SaveViewState()

When implemented by a class, saves the current view state of the DataSourceExpression object.(Inherited from DataSourceExpression.)

System_CAPS_pubinterfaceSystem_CAPS_privmethodIStateManager.TrackViewState()

When 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.)

System_CAPS_pubinterfaceSystem_CAPS_privpropertyIStateManager.IsTrackingViewState

When implemented by a class, gets a value that indicates whether a data source expression object is tracking its view state changes.(Inherited from DataSourceExpression.)

The DynamicFilterExpression class enables you to modify a database query using the values that are assigned in a DynamicFilter control. This control delegates the task of building of the IQueryable query to a specialized control such as QueryableFilterRepeater control or DynamicFilter control.

The filter controls in turn delegate the building of the query to the filter template that they reference. The query is then executed by the data source control that is referenced by the QueryExtender control.

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

  • Add a QueryExtender control to the page.

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

  • Add a DynamicFilterExpression object as a child of the QueryExtender control.

  • Set the ControlID property of the DynamicFilterExpression object to reference the filter control.

In the previous steps it is assumed that the related filter controls, data-bound controls, and data source control are defined in the page.

The following example shows how to use the DynamicFilterExpression control to select a filter template in a page. The filter template is selected by the DynamicFilter control that is identified by DynamicFilterExpression control through its ControID property.

<asp:QueryExtender ID="QueryExtender1" 
    TargetControlID="GridDataSource" runat="server">
    <asp:DynamicFilterExpression ControlID="CategoryFilterID" />
</asp:QueryExtender>

.NET Framework
Available since 4.0

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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