ClientScriptManager.RegisterForEventValidation Method

Reference

Definition

Namespace:: System.Web.UI

Assembly:: System.Web.dll

Important

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Registers an event reference for validation.

Overloads

RegisterForEventValidation(String, String)	Registers an event reference for validation with a unique control ID and event arguments representing the client control generating the event.
RegisterForEventValidation(String)	Registers an event reference for validation with a unique control ID representing the client control generating the event.
RegisterForEventValidation(PostBackOptions)	Registers an event reference for validation with PostBackOptions.

RegisterForEventValidation(String, String)

Registers an event reference for validation with a unique control ID and event arguments representing the client control generating the event.

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

uniqueId: String

A unique ID representing the client control generating the event.

argument: String

Event arguments passed with the client event.

Exceptions

InvalidOperationException

The method is called prior to the Render(HtmlTextWriter) method.

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)
    {
        try
        {
            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>
<body>
    <form id="Form1" runat="server">
    <div>
      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"/>
    </div>
    </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
        
        Try
            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>
<body>
    <form id="Form1" runat="server">
    <div>
      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"/>
    </div>
    </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">
    <div>
        <asp:DropDownList ID="DropDownList1" runat="server"></asp:DropDownList>
        <asp:Button ID="Button1" runat="server" Text="Postback to server for validation" />
    </div>
    </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">
    <div>
        <asp:DropDownList ID="DropDownList1" runat="server">
        </asp:DropDownList>
        <asp:Button ID="Button1" runat="server" Text="Postback to server for validation" />
    </div>
    </form>
</body>
</html>

Applies to

RegisterForEventValidation(String)

Registers an event reference for validation with a unique control ID representing the client control generating the event.

public:
 void RegisterForEventValidation(System::String ^ uniqueId);

public void RegisterForEventValidation (string uniqueId);

member this.RegisterForEventValidation : string -> unit

Public Sub RegisterForEventValidation (uniqueId As String)

Parameters

uniqueId: String

A unique ID representing the client control generating the event.

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)
    {
        try
        {
            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>
<body>
    <form id="Form1" runat="server">
    <div>
      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"/>
    </div>
    </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
        
        Try
            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>
<body>
    <form id="Form1" runat="server">
    <div>
      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"/>
    </div>
    </form>
</body>
</html>

Remarks

For more information and examples, see the RegisterForEventValidation method.

Applies to

RegisterForEventValidation(PostBackOptions)

Registers an event reference for validation with PostBackOptions.

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

options: PostBackOptions

A PostBackOptions object that specifies how client JavaScript is generated to initiate a postback event.

Remarks

For more information and examples, see the RegisterForEventValidation method.

Applies to

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ClientScriptManager.RegisterForEventValidation Method

Definition

Overloads

RegisterForEventValidation(String, String)

Parameters

Exceptions

Examples

See also

Applies to

RegisterForEventValidation(String)

Parameters

Examples

Remarks

See also

Applies to

RegisterForEventValidation(PostBackOptions)

Parameters

Remarks

See also

Applies to

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