How to invoke function in asp.net using javascript?

Question

I'm using the jquery plugin tablednd

$(document).ready(function () {
    $('#mygridview').tableDnD();
})

to make my rows in my gridview draggable. When I've dragged a row I want to invoke a function in asp.net to save the positions of the rows. But I can't find a proper event on gridview that only reacts on clicking on a row.

There is a onDrop method in tableDnd.

$(document).ready(function () {
    $('#mygridview').tableDnD({
      onDrop: function(table, row) {
   });
})

But how could I from there invoke a asp.net method? I've read some about ajax post but I don't understand that.

And I also read about using PageMethods but it didn't invoke my function.

The question is how can I write something that executes an update on a table in my database?

UPDATED:

I solved it using the IPostBackEventHandler method.

I had to extend both my user control and my page with IPostBackEventHandler and then added the public void RaisePostBackEvent(string eventArgument) function on both the user control and page. And finally:

onDrop: function (table, row) {
                __doPostBack('<%= this.UniqueID %>', 'Select');
            }

If someone got problem with onDrop, the solution is you have to give ID to each row like this:

    var i = 0;
    $("#<%= gridviewID.ClientID %>").find('tr').each(function () {
        $(this).attr('id', i++);
    });

above the initiation of the tablednd.

Thanks!

Answer 1

There are two ways in general, one using AJAX and second, using postbacks.

The AJAX way:

1. Add ScriptManager to the page, like this:

    <asp:ScriptManager runat="server" ID="ScriptManager1" EnablePageMethods="true" EnablePartialRendering="true" /> 

2. Make the server side method to be called as public static. Also mark it with the System.Web.Services.WebMethod attribute, like this:

    [WebMethod] public static string DoServerStuff(string parameter) { return "Parameter passed: " + parameter; } 

3. Call it from the client side, via the PageMethods class, like this:

    function doClientStuff() { var result = PageMethods.DoServerStuff('test parameter'); alert(result); } 

4. For doing the same thing using jQuery check this out.

---

The postbacks way:

1. Make the page (that contains the method to be called) implement the IPostBackEventHandler interface.

2. Call the __doPostback method on the client side, like this:

    function doClientStuff() { var result = __doPostBack('<%= this.UniqueID %>', 'Select'); } 

3. Implement the server side logic inside the IPostBackEventHandler.RaisePostBackEvent method of the page.

4. More on the raising postbacks from the client side here .