Question

I tried to call a c# function from JavaScript – I want to pass the parameter along with that method, but how do I pass the parameter?

Below is the javascript in the aspx page:

function CallCodeBehind(id) {
    var a = '<%=CallFromJS(--parameter need pass here --)%>';
}

The below method is in the code-behind

public string CallFromJS(id) {
    int id=id;
    getNames(id);    
    return null;
}

And the Button code is:

<Button ID="Button1" runat="server" OnClientClick="CallCodeBehind(<%=(id)%>)"     Text="Upload" />

Answer 1

WebMethods can have parameters, but method has to be static.

Server side (*.cs code behind) :

[WebMethod]
public static string Hello(string name)
{
  return "Hello " + name;
}

And then call it from javascript like this :

<script type="text/javascript">
    function SayHelloToMe(param) {
      PageMethods.Hello(param, OnSuccess, OnError);
    }

    function OnSuccess(response) {
      alert(response);
    }

    function OnError(error) {
      alert(error);  
    }  
</script>

and button :

<Button ID="Button1" runat="server" OnClientClick="SayHelloToMe('<%=(id)%>')"     Text="Upload" />

Of course id has to be public, and on that form you have to have ScriptManager with PageMethods enabled, like this :

<asp:ScriptManager ID="scMan" runat="server" EnablePageMethods="true"></asp:ScriptManager>