Using PageMethods to access MultiiView Control ASP.Net

Question

I have a multiview on my aspx page whose ActiveViewIndex I want to set using javascript. for this I have used UpdatePanel inside which the MultiView control is placed. I have enabled the EnablePageMethods="True" of the ScriptManager.

Whenever I am calling the Server Method I am getting "Object reference not set to an Instance of an Object"

 
function CallScreens(id) 
{

//var id,var type
//Call server side function
alert('Hello');
PageMethods.SetScreens("-1","screen",OnCallSumComplete,OnCallSumError,"");
}

The Server Side code is as given below

 
  [System.Web.Services.WebMethod]

    public static void SetScreens(string id,string Type)
    {

        try
        {
            TreeView obj = new TreeView();//Name of my Class
            obj.MultiView1.ActiveViewIndex=1;
        }

        catch (Exception ex)
        {

            throw ex;

        }

    }
 

Answer 1

Are you getting this error because MultiView1 has not been instantiated in the TreeView object? Also, webmethods don't have access to the page elements because they are treated as static.