[WebMethod]
        [ScriptMethod(ResponseFormat = ResponseFormat.Json,
        UseHttpGet = true, XmlSerializeString = false)]
        public static List<User> webmethod2()
        {
            List<User> users = new List<User>();
            User u1 = new User();
            u1.Idnt = "5";
            u1.FirstName = "abc";
            User u2 = new User();
            u2.Idnt = "25";
            u2.FirstName = "2_abc";
            //
            users.Add(u1);
            users.Add(u2);

            return users;
        }

Ext.onReady(function() {
Ext.define('myModel', {
        extend: 'Ext.data.Model',
        fields: ['Idnt','FirstName']
     });   
     
     var store = Ext.create('Ext.data.Store', {
        model: 'myModel',
        proxy: {
             type: 'ajax',
             url: 'http://localhost:61867/DataWorker.aspx/webmethod2',
             reader: {
                 type: 'json',
                 root: 'd'
             },
		headers: {
        	'Content-Type': 'application/json; charset=utf-8'
    		}
         },
         autoLoad: true
    });
 
    Ext.create('Ext.grid.Panel', {
        store: store,
        columns: [
        {
            text     : 'Company',
            id: 'Idnt'
        },
        {
            text     : 'Price',
            id: 'FirstName'
        }
        ],
        height: 350,
        width: 600,
        title: 'grid',
        renderTo: 'grid1'
    });

});

columns: [
        {
            text     : 'Company',
            dataIndex: 'Idnt'
        },
        {
            text     : 'Price',
            dataIndex: 'FirstName'
        }
        ],

public static void webmethod3(HttpContext con)
public static string webmethod3(string str)
public static string webmethod3(string str, string str2)
        

        [WebMethod]
        [ScriptMethod(ResponseFormat = ResponseFormat.Json, UseHttpGet = false, 
        XmlSerializeString = false)]
        public static void webmethod3()
        {
            HttpContext.Current.Request.InputStream.Position = 0;

            int bytesToRead = HttpContext.Current.Request.TotalBytes;
            MemoryStream mem = new MemoryStream(HttpContext.Current.Request.BinaryRead(bytesToRead));

            StreamReader reader = new StreamReader(mem);

            string s = reader.ReadToEnd();
         
         
        }

writer: {
                type: 'json',
                writeAllFields: true,
	        root: 'd'
             },

{__type: "TestExtJS.User", Idnt: "ап", FirstName: "2_abc", id: "myModel-3"}