Calling ASP.Net WebMethod using jQuery AJAX

12:48:00 AM Mahesh Kumar Yadav 0 Comments


jQuery allows you to call Server Side ASP.net methods from client side without any PostBack. Actually it is an AJAX call to the server but it allows us to call the method or function defined server side.
Syntax
The following picture describes the syntax of the jQuery AJAX call.
WebMethod using jQuery AJAX
HTML Markup
The following HTML Markup consists of an ASP.Net TextBox and an HTML Button.
<div>
Your Name :
<asp:TextBox ID="txtUserName" runat="server"></asp:TextBox>
<input id="btnGetTime" type="button" value="Show Current Time"
    onclick = "ShowCurrentTime()" />
</div>
Client Side Script
When the Button is clicked the ShowCurrentTime JavaScript function is executed which makes an AJAX call to the GetCurrentTime WebMethod. The value of the TextBox is passed as parameter to the WebMethod.
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js" type="text/javascript"></script>
<script type = "text/javascript">
function ShowCurrentTime() {
    $.ajax({
        type: "POST",
        url: "CS.aspx/GetCurrentTime",
        data: '{name: "' + $("#<%=txtUserName.ClientID%>")[0].value + '" }',
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: OnSuccess,
        failure: function(response) {
            alert(response.d);
        }
    });
}
function OnSuccess(response) {
    alert(response.d);
}
</script>
The WebMethod
The following WebMethod returns a greeting message to the user along with the current server time. An important thing to note is that the method is declared as static(C#) and Shared (VB.Net) and is decorated with WebMethod attribute, this is necessary otherwise the method will not be called from client side jQuery AJAX call.
C#
[System.Web.Services.WebMethod]
public static string GetCurrentTime(string name)
{
    return "Hello " + name + Environment.NewLine + "The Current Time is: "
        + DateTime.Now.ToString();
}
VB.Net
<System.Web.Services.WebMethod()> _
Public Shared Function GetCurrentTime(ByVal name As StringAs String
   Return "Hello " & name & Environment.NewLine & "The Current Time is: " & _
            DateTime.Now.ToString()
End Function
Source: Internet

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