Ajax with page method

Question

I have a gridview inside the update panel, and I have javascript that calls the page method using jquery. I would like the page method to update the gridview based on the parameter that it received from the ajax call.

So far I have the following:

1) in javascript there is a function that calls the page method:

function GetNewDate(thedateitem) {

    DateString = (valid json date format that works)

    $.ajax({
        type: "POST",
        url: "./CallHistory.aspx/ResetDate",
        contentType: "application/json; charset=utf-8",
        data: DateString,
        dataType: "json",
        success: successFn,
        error: errorFn
    }) 
};

2) On the aspx page, I have:

    <asp:UpdatePanel ID="MyPanel" runat="server">
        <ContentTemplate>
                <asp:GridView ID="MyGrid">

3) In the code behind:

public partial class Pages_CallHistory : System.Web.UI.Page
{
    List<ViewCallHistoryModel> TheCallHistory;

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            TheDate = new DateTime(2011, 1, 13);
            LoadCallHistory(TheDate);
            MyGrid.Datasource = TheCallHistory;
            MyGrid.Databind;
        }
    }

    protected void LoadCallHistory(DateTime TheDate)
    {
        linq query that fills the variable TheCallHistory
    }

    [WebMethod]
    public static void ResetDate(DateTime TheNewDate)
    {
        var test = new Pages_CallHistory();
        var test2 = test.LoadCallHistory(TheNewDate.Date);
        //test2 loads fine

        test.GridCallHistory.DataSource = test2; 
        //this is not underlined but bugs at runtime
        //Object reference not set to an instance of an object.

        test.GridCallHistory.DataBind();
        test.MyPanel.Update(); 
        //this is not underlined but doesn't get executed because
        //because it stops at the line above

        //I'd like to update the content of 
        //the gridview on the page with the updated gridview.
    }

What I would like to do in the page method is 1) call LoadCallHistory with the new date parameter and 2) pass the gridview MyGrid to re-bind to the new data that is in TheCallHistory.

I struggle with this page method; it does not work and i am stuck. How it's done?

Answer 1

ok, _doPostBack javascript:

   __doPostBack('MyPanel', DateString);

, .

Answer 2

. , .