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public:
void RegisterForEventValidation(System::String ^ uniqueId, System::String ^ argument);
public void RegisterForEventValidation (string uniqueId, string argument);
member this.RegisterForEventValidation : string * string -> unit
Public Sub RegisterForEventValidation (uniqueId As String, argument As String)
Parameters
Examples
The following code example demonstrates using the
RegisterForEventValidation
method and the
ValidateEvent
method to register a callback for validation and to validate that the callback originated from the page. To improve on the validation shown in the example, you could modify the validation
argument
parameter to contain information specific to the user such as an identity or role
<%@ Page Language="C#" %>
<%@ Implements Interface="System.Web.UI.ICallbackEventHandler" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server" >
string _cbMessage = "";
// Define method that processes the callbacks on server.
public void RaiseCallbackEvent(String eventArgument)
Page.ClientScript.ValidateEvent(button1.UniqueID, this.ToString());
_cbMessage = "Correct event raised callback.";
catch (Exception ex)
_cbMessage = "Incorrect event raised callback.";
// Define method that returns callback result.
public string GetCallbackResult()
return _cbMessage;
protected void Page_Load(object sender, EventArgs e)
if (!IsPostBack)
ClientScriptManager cs = Page.ClientScript;
String cbReference = cs.GetCallbackEventReference("'" +
Page.UniqueID + "'", "arg", "ReceiveServerData", "",
"ProcessCallBackError", false);
String callbackScript = "function CallTheServer(arg, context) {" +
cbReference + "; }";
cs.RegisterClientScriptBlock(this.GetType(), "CallTheServer",
callbackScript, true);
protected override void Render(HtmlTextWriter writer)
Page.ClientScript.RegisterForEventValidation(button1.UniqueID, this.ToString());
base.Render(writer);
</script>
<script type="text/javascript">
var value1 = new Date();
function ReceiveServerData(arg, context)
Message.innerText = arg;
Label1.innerText = "Callback completed at " + value1;
value1 = new Date();
function ProcessCallBackError(arg, context)
Message.innerText = 'An error has occurred.';
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>CallBack Event Validation Example</title>
</head>
<form id="Form1" runat="server">
Callback result: <span id="Message"></span>
<br /> <br />
<input type="button"
id="button1"
runat="server"
value="ClientCallBack"
onclick="CallTheServer(value1, null )"/>
<br /> <br />
<asp:Label id="Label1" runat="server"/>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<%@ Implements Interface="System.Web.UI.ICallbackEventHandler" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Dim _cbMessage As String = ""
' Define method that processes the callbacks on server.
Public Sub RaiseCallbackEvent(ByVal eventArgument As String) _
Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent
Page.ClientScript.ValidateEvent(button1.UniqueID, Me.ToString())
_cbMessage = "Correct event raised callback."
Catch ex As Exception
_cbMessage = "Incorrect event raised callback."
End Try
End Sub
' Define method that returns callback result.
Public Function GetCallbackResult() _
As String Implements _
System.Web.UI.ICallbackEventHandler.GetCallbackResult
Return _cbMessage
End Function
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
If (Not IsPostBack) Then
Dim cs As ClientScriptManager = Page.ClientScript
Dim cbReference As String = cs.GetCallbackEventReference("'" & _
Page.UniqueID & "'", "arg", "ReceiveServerData", "", _
"ProcessCallBackError", False)
Dim callbackScript As String = "function CallTheServer(arg, context) {" & _
cbReference & "; }"
cs.RegisterClientScriptBlock(Me.GetType(), "CallTheServer", _
callbackScript, True)
End If
End Sub
Protected Overrides Sub Render(ByVal writer As System.Web.UI.HtmlTextWriter)
Page.ClientScript.RegisterForEventValidation(button1.UniqueID, Me.ToString())
MyBase.Render(writer)
End Sub
</script>
<script type="text/javascript">
var value1 = new Date();
function ReceiveServerData(arg, context)
Message.innerText = arg;
Label1.innerText = "Callback completed at " + value1;
value1 = new Date();
function ProcessCallBackError(arg, context)
Message.innerText = 'An error has occurred.';
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>CallBack Event Validation Example</title>
</head>
<form id="Form1" runat="server">
Callback result: <span id="Message"></span>
<br /> <br />
<input type="button"
id="button1"
runat="server"
value="ClientCallBack"
onclick="CallTheServer(value1, null )"/>
<br /> <br />
<asp:Label id="Label1" runat="server"/>
</form>
</body>
</html>
The following code example demonstrates using the
RegisterForEventValidation
method to register a callback for validation.
<%@ Page EnableEventValidation="true" Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Register an option for event validation</title>
<script runat="server">
protected override void Render(HtmlTextWriter writer)
ClientScript.RegisterForEventValidation("DropDownList1", "This is Option 1");
ClientScript.RegisterForEventValidation("DropDownList1", "This is Option 2");
ClientScript.RegisterForEventValidation("DropDownList1", "This is Option 3");
// Uncomment the line below when you want to specifically register the option for event validation.
// ClientScript.RegisterForEventValidation("DropDownList1", "Is this option registered for event validation?");
base.Render(writer);
</script>
<script type="text/javascript">
function Initialize()
var oOption = document.createElement("OPTION");
document.all("DropDownList1").options.add(oOption);
oOption.innerText = "This is Option 1";
oOption = document.createElement("OPTION");
document.all("DropDownList1").options.add(oOption);
oOption.innerText = "This is Option 2";
oOption = document.createElement("OPTION");
document.all("DropDownList1").options.add(oOption);
oOption.innerText = "This is Option 3";
oOption = document.createElement("OPTION");
document.all("DropDownList1").options.add(oOption);
oOption.innerText = "Is this option registered for event validation?";
</script>
</head>
<body onload="Initialize();">
<form id="form1" runat="server">
<asp:DropDownList ID="DropDownList1" runat="server"></asp:DropDownList>
<asp:Button ID="Button1" runat="server" Text="Postback to server for validation" />
</form>
</body>
</html>
<%@ Page EnableEventValidation="true" Language="VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>Register an option for event validation</title>
<script runat="server">
Protected Overrides Sub Render(ByVal writer As System.Web.UI.HtmlTextWriter)
ClientScript.RegisterForEventValidation("DropDownList1", "This is Option 1")
ClientScript.RegisterForEventValidation("DropDownList1", "This is Option 2")
ClientScript.RegisterForEventValidation("DropDownList1", "This is Option 3")
' Uncomment the line below when you want to specifically register the option for event validation.
' ClientScript.RegisterForEventValidation("DropDownList1", "Is this option registered for event validation?")
MyBase.Render(writer)
End Sub
</script>
<script type="text/javascript">
function Initialize()
var oOption = document.createElement("OPTION");
document.all("DropDownList1").options.add(oOption);
oOption.innerText = "This is Option 1";
oOption = document.createElement("OPTION");
document.all("DropDownList1").options.add(oOption);
oOption.innerText = "This is Option 2";
oOption = document.createElement("OPTION");
document.all("DropDownList1").options.add(oOption);
oOption.innerText = "This is Option 3";
oOption = document.createElement("OPTION");
document.all("DropDownList1").options.add(oOption);
oOption.innerText = "Is this option registered for event validation?";
</script>
</head>
<body onload="Initialize();">
<form id="form1" runat="server">
<asp:DropDownList ID="DropDownList1" runat="server">
</asp:DropDownList>
<asp:Button ID="Button1" runat="server" Text="Postback to server for validation" />
</form>
</body>
</html>
public:
void RegisterForEventValidation(System::String ^ uniqueId);
public void RegisterForEventValidation (string uniqueId);
member this.RegisterForEventValidation : string -> unit
Public Sub RegisterForEventValidation (uniqueId As String)
Parameters
Examples
The following example shows how to use the
RegisterForEventValidation
method and the
ValidateEvent
method in order to register a callback for validation, and how to validate that the callback originated from the page.
<%@ Page Language="C#" %>
<%@ Implements Interface="System.Web.UI.ICallbackEventHandler" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server" >
string _cbMessage = "";
// Define method that processes the callbacks on server.
public void RaiseCallbackEvent(String eventArgument)
Page.ClientScript.ValidateEvent(button1.UniqueID);
_cbMessage = "Correct event raised callback.";
catch (Exception ex)
_cbMessage = "Incorrect event raised callback.";
// Define method that returns callback result.
public string GetCallbackResult()
return _cbMessage;
protected void Page_Load(object sender, EventArgs e)
if (!IsPostBack)
ClientScriptManager cs = Page.ClientScript;
String cbReference = cs.GetCallbackEventReference("'" +
Page.UniqueID + "'", "arg", "ReceiveServerData", "",
"ProcessCallBackError", false);
String callbackScript = "function CallTheServer(arg, context) {" +
cbReference + "; }";
cs.RegisterClientScriptBlock(this.GetType(), "CallTheServer",
callbackScript, true);
protected override void Render(HtmlTextWriter writer)
Page.ClientScript.RegisterForEventValidation(button1.UniqueID);
base.Render(writer);
</script>
<script type="text/javascript">
var value1 = new Date();
function ReceiveServerData(arg, context) {
Message.innerText = arg;
Label1.innerText = "Callback completed at " + value1;
value1 = new Date();
function ProcessCallBackError(arg, context) {
Message.innerText = 'An error has occurred.';
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
<title>CallBack Event Validation Example</title>
</head>
<form id="Form1" runat="server">
Callback result: <span id="Message"></span>
<br /> <br />
<input type="button"
id="button1"
runat="server"
value="ClientCallBack"
onclick="CallTheServer(value1, null )"/>
<br /> <br />
<asp:Label id="Label1" runat="server"/>
</form>
</body>
</html>
<%@ Page Language="VB" %>
<%@ Implements Interface="System.Web.UI.ICallbackEventHandler" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
Dim _cbMessage As String = ""
' Define method that processes the callbacks on server.
Public Sub RaiseCallbackEvent(ByVal eventArgument As String) _
Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent
Page.ClientScript.ValidateEvent(button1.UniqueID)
_cbMessage = "Correct event raised callback."
Catch ex As Exception
_cbMessage = "Incorrect event raised callback."
End Try
End Sub
' Define method that returns callback result.
Public Function GetCallbackResult() _
As String Implements _
System.Web.UI.ICallbackEventHandler.GetCallbackResult
Return _cbMessage
End Function
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
If (Not IsPostBack) Then
Dim cs As ClientScriptManager = Page.ClientScript
Dim cbReference As String = cs.GetCallbackEventReference("'" & _
Page.UniqueID & "'", "arg", "ReceiveServerData", "", _
"ProcessCallBackError", False)
Dim callbackScript As String = "function CallTheServer(arg, context) {" & _
cbReference & "; }"
cs.RegisterClientScriptBlock(Me.GetType(), "CallTheServer", _
callbackScript, True)
End If
End Sub
Protected Overrides Sub Render(ByVal writer As System.Web.UI.HtmlTextWriter)
Page.ClientScript.RegisterForEventValidation(button1.UniqueID)
MyBase.Render(writer)
End Sub
</script>
<script type="text/javascript">
var value1 = new Date();
function ReceiveServerData(arg, context)
Message.innerText = arg;
Label1.innerText = "Callback completed at " + value1;
value1 = new Date();
function ProcessCallBackError(arg, context)
Message.innerText = 'An error has occurred.';
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>CallBack Event Validation Example</title>
</head>
<form id="Form1" runat="server">
Callback result: <span id="Message"></span>
<br /> <br />
<input type="button"
id="button1"
runat="server"
value="ClientCallBack"
onclick="CallTheServer(value1, null )"/>
<br /> <br />
<asp:Label id="Label1" runat="server"/>
</form>
</body>
</html>
Remarks
For more information and examples, see the
RegisterForEventValidation
method.
public:
void RegisterForEventValidation(System::Web::UI::PostBackOptions ^ options);
public void RegisterForEventValidation (System.Web.UI.PostBackOptions options);
member this.RegisterForEventValidation : System.Web.UI.PostBackOptions -> unit
Public Sub RegisterForEventValidation (options As PostBackOptions)
Parameters
