无法在JavaScript中调用C＃方法

Question

i want to call my webmethod( C# method) in aspx page in javascript ajax call. so in URL i can pass the Test.aspx/MyMethodName

[WebMethod]
[ScriptMethod(UseHttpGet = true, ResponseFormat = ResponseFormat.Json)]
public static string Loadsites() {
    var jsondata = JsonConvert.SerializeObject(lstsitename);
    // test.Visible = true; return jsondata;
} 

$(document).ready(function () {        
   LoadGrid = function () {
    alert('Loading Grid data');
    jQuery("#Grid").jqGrid({           
        mtype: 'POST',
        url: 'Test.aspx/Loadsites',
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        colNames: ['SiteName', 'Description' ],
        colModel: [
                    { name: 'SiteName', index: 'SiteName' },
                    { name: 'Description', index: 'Description' }
        ],
        sortname: "SiteName",
        rowNum: 10,
        viewrecords: true,
        sortorder: "asc",
        caption: "Site Details",
        width: "auto",
        height: "auto",
        pager: '#Pager'

    });

    jQuery("#Grid").jqGrid('navGrid', '#Pager', { edit: true, add: true, del: true });
 }
});

i tried static in method but didnt work as well

Answer 1

If you place this attribute [WebMethod] above your method signature, you could achieve that you want.

Furthermore, you method should be defined as static .

Answer 2

There are errors on both sides (on server side and on the client side).

On the server side you declare string as the result of Loadsites and you call JsonConvert.SerializeObject explicitly. It's wrong. WebMethod is designed so that it makes conversion to JSON or XML internally . So one should return object (just return lstsitename ;) instead of string . WebMethod will converts the results to JSON based on contentType of the HTTP request. If you call JsonConvert.SerializeObject additionally then the returned data is string which contains quotes, for example [{"myCol1": "value1"}] . Because of JSON standards such string will be converted to JSON once more and the resulting data returned from the server will be like "[{\\"myCol1\\": "value1\\"}]" . Conversion of correct JSON data [{"myCol1": "value1"}] would get array of objects in JavaSript on the client side. Parsing the twice converted data "[{\\"myCol1\\": "value1\\"}]" will produce the string '[{"myCol1": "value1"}]' instead of array of objects.

There are some important errors on the client side too (in the JavaScript code which creates jqGrid):

• you use unknown option dataType: "json" instead of datatype: "json" . As the result jqGrid will use default value datatype: "xml" which is wrong.
• you use unknown option contentType: "application/json; charset=utf-8" instead of the usage of ajaxGridOptions which allows to specify Ajax options: ajaxGridOptions: { contentType: "application/json; charset=utf-8" }
• you should add loadonce: true option if you didn't implemented server side paging of data.
• you assign LoadGrid without declaring of the variable and you don't call the function inside of $(document).ready(...); . Instead of that you should just execute once the corresponding code which creates jqGrid and add navigator bar by calling of navGrid .