Page.RegisterRequiresPostBack Method
Assembly: System.Web (in system.web.dll)
'Declaration Public Sub RegisterRequiresPostBack ( _ control As Control _ ) 'Usage Dim instance As Page Dim control As Control instance.RegisterRequiresPostBack(control)
public void RegisterRequiresPostBack ( Control control )
public function RegisterRequiresPostBack ( control : Control )
Not applicable.
Parameters
- control
The control to be registered.
| Exception type | Condition |
|---|---|
|
The control to register does not implement the IPostBackDataHandler interface. |
The control to be registered must implement the IPostBackDataHandler interface or an HttpException is raised. When implemented by a control, the IPostBackDataHandler interface enables handling of post back data and raising of any post back data changed events. For more information on the server control event model, see ASP.NET Server Control Event Model.
Register controls with the page at or before the Page_PreRender event of the page life cycle.
The following code example uses the RegisterRequiresPostBack method to require a text box control, myTextBox, to be posted back before any code associated with the text box can execute. TextBox controls implement the IPostBackDataHandler interface.
Security Note: |
|---|
|
This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview (Visual Studio). |
Sub Text_Change(ByVal sender As Object, ByVal e As EventArgs) myLabel.Text = "<b>Welcome " + myTextBox.Text + " to ASP.NET</b>" End Sub 'Text_Change Protected Sub Page_PreRender(ByVal sender As Object, ByVal e As System.EventArgs) Me.RegisterRequiresPostBack(myTextBox) End Sub
void Text_Change(Object sender, EventArgs e)
{
myLabel.set_Text("<b>Welcome " + myTextBox.get_Text()
+ " to ASP.NET</b>");
}
void Page_Load(Object sender, EventArgs e)
{
this.RegisterRequiresPostBack(myTextBox);
}
Security Note: