将字符串从代码传递到ajax

Question

I am accessing a method on the server side. The only problem is that I don't have alot of experience in AJAx. I am unable to retrieve the returned string in the ajax from the .cs method

$.ajax({
  type: 'GET',
  url: '/frmGpsMap.aspx?name=load',
  dataType: 'text',
  success: function(data) {
    alert(data.d);
  }
});

 protected void Page_Load(object sender, EventArgs e)
        {
            string crrName = Request.QueryString["name"];
            if (!String.IsNullOrEmpty(crrName))
            {
                if (crrName.ToLower().Equals("load"))
                {
                 string fh=   loadKMLFileToString();
                 hdnUsername.Value = fh;
                }
            }
        }

        public string loadKMLFileToString()
        {
            return "hello world";
        }

The alert is returning the html of the page. I want to display the "Hello World" string

Answer 1

To get the code behind method to work with ajax you need to use System.Web.Services.WebMethod. By default you need to use POST unless you specify HTTP GET attribute in code behind

[System.Web.Services.WebMethod]
public static string LoadKMLFileToString()
{
    return "Hello World";
}

Here is the ajax method for call

$.ajax({
        type: "POST",
        url: "frmGpsMap.aspx/LoadKMLFileToString",
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        success: function(response) {
            alert(response.d),
        failure: function(response) {
            alert(response.d);
        }
    });

I hope it helps. More examples: http://weblogs.asp.net/karan/calling-server-side-method-using-jquery-ajax

Answer 2

I think you can decorate your cs method with the WebMethod attribute and call it directly from ajax. Like this:

 $.ajax({
  ...
  url: '/frmGpsMap.aspx?loadKMLFileToString',
  ...
});


  [System.Web.Services.WebMethod]
    public string loadKMLFileToString()
    {
        return "hello world";
    }

Cheers! =)