<%@ 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">
Public cbCount As Integer = 0
' Define method that processes the callbacks on server.
Public Sub RaiseCallbackEvent(ByVal eventArgument As String) _
Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent
cbCount = Convert.ToInt32(eventArgument) + 1
End Sub
' Define method that returns callback result.
Public Function GetCallbackResult() _
As String Implements _
System.Web.UI.ICallbackEventHandler.GetCallbackResult
Return cbCount.ToString()
End Function
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
' Define a StringBuilder to hold messages to output.
Dim sb As New StringBuilder()
' Check if this is a postback.
sb.Append("No page postbacks have occurred.")
If (Page.IsPostBack) Then
sb.Append("A page postback has occurred.")
End If
' Write out any messages.
MyLabel.Text = sb.ToString()
' Get a ClientScriptManager reference from the Page class.
Dim cs As ClientScriptManager = Page.ClientScript
' Define one of the callback script's context.
' The callback script will be defined in a script block on the page.
Dim context1 As New StringBuilder()
context1.Append("function ReceiveServerData1(arg, context)")
context1.Append("{")
context1.Append("Message1.innerText = arg;")
context1.Append("value1 = arg;")
context1.Append("}")
' Define callback references.
Dim cbReference1 As String = cs.GetCallbackEventReference(Me, "arg", _
"ReceiveServerData1", context1.ToString())
Dim cbReference2 As String = cs.GetCallbackEventReference("'" & _
Page.UniqueID & "'", "arg", "ReceiveServerData2", "", "ProcessCallBackError", False)
Dim callbackScript1 As String = "function CallTheServer1(arg, context) {" + _
cbReference1 + "; }"
Dim callbackScript2 As String = "function CallTheServer2(arg, context) {" + _
cbReference2 + "; }"
' Register script blocks will perform call to the server.
cs.RegisterClientScriptBlock(Me.GetType(), "CallTheServer1", _
callbackScript1, True)
cs.RegisterClientScriptBlock(Me.GetType(), "CallTheServer2", _
callbackScript2, True)
End Sub
</script>
<script type="text/javascript">
var value1 = 0;
var value2 = 0;
function ReceiveServerData2(arg, context)
{
Message2.innerText = arg;
value2 = arg;
}
function ProcessCallBackError(arg, context)
{
Message2.innerText = 'An error has occurred.';
}
</script>
<html >
<head>
<title>ClientScriptManager Example</title>
</head>
<body>
<form id="Form1"
runat="server">
<div>
Callback 1 result: <span id="Message1">0</span>
<br />
Callback 2 result: <span id="Message2">0</span>
<br /> <br />
<input type="button"
value="ClientCallBack1"
onclick="CallTheServer1(value1, alert('Increment value'))"/>
<input type="button"
value="ClientCallBack2"
onclick="CallTheServer2(value2, alert('Increment value'))"/>
<br /> <br />
<asp:Label id="MyLabel"
runat="server"></asp:Label>
</div>
</form>
</body>
</html>
<%@ 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">
public int cbCount = 0;
// Define method that processes the callbacks on server.
public void RaiseCallbackEvent(String eventArgument)
{
cbCount = Convert.ToInt32(eventArgument) + 1;
}
// Define method that returns callback result.
public string GetCallbackResult()
{
return cbCount.ToString();
}
protected void Page_Load(object sender, EventArgs e)
{
// Define a StringBuilder to hold messages to output.
StringBuilder sb = new StringBuilder();
// Check if this is a postback.
sb.Append("No page postbacks have occurred.");
if (Page.IsPostBack)
{
sb.Append("A page postback has occurred.");
}
// Write out any messages.
MyLabel.Text = sb.ToString();
// Get a ClientScriptManager reference from the Page class.
ClientScriptManager cs = Page.ClientScript;
// Define one of the callback script's context.
// The callback script will be defined in a script block on the page.
StringBuilder context1 = new StringBuilder();
context1.Append("function ReceiveServerData1(arg, context)");
context1.Append("{");
context1.Append("Message1.innerText = arg;");
context1.Append("value1 = arg;");
context1.Append("}");
// Define callback references.
String cbReference1 = cs.GetCallbackEventReference(this, "arg",
"ReceiveServerData1", context1.ToString());
String cbReference2 = cs.GetCallbackEventReference("'" +
Page.UniqueID + "'", "arg", "ReceiveServerData2", "",
"ProcessCallBackError", false);
String callbackScript1 = "function CallTheServer1(arg, context) {" +
cbReference1 + "; }";
String callbackScript2 = "function CallTheServer2(arg, context) {" +
cbReference2 + "; }";
// Register script blocks will perform call to the server.
cs.RegisterClientScriptBlock(this.GetType(), "CallTheServer1",
callbackScript1, true);
cs.RegisterClientScriptBlock(this.GetType(), "CallTheServer2",
callbackScript2, true);
}
</script>
<script type="text/javascript">
var value1 = 0;
var value2 = 0;
function ReceiveServerData2(arg, context)
{
Message2.innerText = arg;
value2 = arg;
}
function ProcessCallBackError(arg, context)
{
Message2.innerText = 'An error has occurred.';
}
</script>
<html >
<head id="Head1" runat="server">
<title>ClientScriptManager Example</title>
</head>
<body>
<form id="Form1"
runat="server">
<div>
Callback 1 result: <span id="Message1">0</span>
<br />
Callback 2 result: <span id="Message2">0</span>
<br /> <br />
<input type="button"
value="ClientCallBack1"
onclick="CallTheServer1(value1, alert('Increment value'))"/>
<input type="button"
value="ClientCallBack2"
onclick="CallTheServer2(value2, alert('Increment value'))"/>
<br /> <br />
<asp:Label id="MyLabel"
runat="server"></asp:Label>
</div>
</form>
</body>
</html>