DataBoundControl.PerformSelect Method
Definition
Important
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Retrieves data from the associated data source.
protected:
override void PerformSelect();protected override void PerformSelect ();override this.PerformSelect : unit -> unitProtected Overrides Sub PerformSelect ()Examples
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 override void PerformSelect() {
// Call OnDataBinding here if bound to a data source using the
// DataSource property (instead of a DataSourceID), because the
// databinding statement is evaluated before the call to GetData.
if (!IsBoundUsingDataSourceID) {
OnDataBinding(EventArgs.Empty);
}
// The GetData method retrieves the DataSourceView object from
// the IDataSource associated with the data-bound control.
GetData().Select(CreateDataSourceSelectArguments(),
OnDataSourceViewSelectCallback);
// The PerformDataBinding method has completed.
RequiresDataBinding = false;
MarkAsDataBound();
// Raise the DataBound event.
OnDataBound(EventArgs.Empty);
}
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
Remarks
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.
