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DataBoundControl.PerformSelect Method

Retrieves data from the associated data source.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)

'Declaration
Protected Overrides Sub PerformSelect

The PerformDataBinding method is called after data is retrieved to bind data to elements of the data-bound control. Derived types override this method to retrieve data only if the default implementation is not adequate. Typically, it is sufficient to provide a DataSourceViewSelectCallback delegate that performs any custom data work, rather than implementing the PerformDataBinding method.

The following code example demonstrates how to override the PerformSelect method to retrieve data from an associated data source using the GetData method and bind it to the elements of the control. This code example is part of a larger example provided for the DataBoundControl class.

    Protected Overrides Sub PerformSelect()

        ' Call OnDataBinding here if bound to a data source using the  
        ' DataSource property (instead of a DataSourceID) because the  
        ' data-binding statement is evaluated before the call to GetData. 
        If Not IsBoundUsingDataSourceID Then
            OnDataBinding(EventArgs.Empty)
        End If 

        ' The GetData method retrieves the DataSourceView object from the  
        ' IDataSource associated with the data-bound control.            
        GetData().Select(CreateDataSourceSelectArguments(), _
            AddressOf OnDataSourceViewSelectCallback)

        ' The PerformDataBinding method has completed.
        RequiresDataBinding = False
        MarkAsDataBound()

        ' Raise the DataBound event.
            OnDataBound(EventArgs.Empty)

    End Sub 'PerformSelect

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0
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