.NET Framework Class Library
ControlOnDataBinding Method

Raises the DataBinding event.

Namespace:   System.Web.UI
Assembly:  System.Web (in System.Web.dll)
Syntax
Protected Overridable Sub OnDataBinding ( _
	e As [%$TOPIC/f9e7sbxh_en-us_VS_110_2_0_0_0_0%] _
)
protected virtual void OnDataBinding(
	[%$TOPIC/f9e7sbxh_en-us_VS_110_2_0_1_0_0%] e
)
protected:
virtual void OnDataBinding(
	[%$TOPIC/f9e7sbxh_en-us_VS_110_2_0_2_0_0%]^ e
)
abstract OnDataBinding : 
        e:[%$TOPIC/f9e7sbxh_en-us_VS_110_2_0_3_0_0%] -> unit  
override OnDataBinding : 
        e:[%$TOPIC/f9e7sbxh_en-us_VS_110_2_0_3_0_1%] -> unit

Parameters

e
Type: SystemEventArgs

An EventArgs object that contains the event data.

Remarks

This method notifies a server control to perform any logic for binding data that is associated with it.

If you want to handle the DataBinding event, you should override this event-handling method. This ensures that all delegates attached to the DataBinding event are invoked.

Examples

The following example demonstrates how to override the OnDataBinding method to add child controls to the parent control from a data source.

' Override to create the repeated items from the DataSource. 
Protected Overrides Sub OnDataBinding(E As EventArgs)
    MyBase.OnDataBinding(e)

    If Not DataSource Is Nothing 
        ' Clear any existing child controls.
        Controls.Clear()
        ' Clear any previous view state for the existing child controls.
        ClearChildViewState()

        ' Iterate over the DataSource, creating a new item for each data item. 
        Dim DataEnum As IEnumerator = DataSource.GetEnumerator()
        Dim I As Integer = 0
        Do While (DataEnum.MoveNext())

            ' Create an item. 
            Dim Item As RepeaterItemVB = New RepeaterItemVB(I, DataEnum.Current)
            ' Initialize the item from the template.
            ItemTemplate.InstantiateIn(Item)
            ' Add the item to the ControlCollection.
            Controls.Add(Item)

            I = I + 1
        Loop 

        ' Prevent child controls from being created again.
        ChildControlsCreated = true
        ' Store the number of items created in view state for postback scenarios.
        ViewState("NumItems") = I
    End If 
End Sub
// Override to create the repeated items from the DataSource. 
protected override void OnDataBinding(EventArgs e) {
    base.OnDataBinding(e);

    if (DataSource != null) {
        // Clear any existing child controls.
        Controls.Clear();
        // Clear any previous view state for the existing child controls.
        ClearChildViewState();

        // Iterate over the DataSource, creating a new item for each data item.
        IEnumerator dataEnum = DataSource.GetEnumerator();
        int i = 0;
        while(dataEnum.MoveNext()) {

            // Create an item.
            RepeaterItem item = new RepeaterItem(i, dataEnum.Current);
            // Initialize the item from the template.
            ItemTemplate.InstantiateIn(item);
            // Add the item to the ControlCollection.
            Controls.Add(item);

            i++;
        }

        // Prevent child controls from being created again.
        ChildControlsCreated = true;
        // Store the number of items created in view state for postback scenarios.
        ViewState["NumItems"] = i;
    }
}
Version Information

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0
Platforms

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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