Jquery - Pass asp button command argument with jquery

Question

I have asp button:

<asp:button ID="btn1" runat="server" CommandArgument="" CssClass="btn1" OnClick="button_click"></asp:button>

and script:

$("a").click(function () {
            var val = $(this).attr('id').toString();                            
            $('.btn1').attr('CommandArgument',val);
            alert($('.btn1').attr('CommandArgument').toString());
            $('.btn1').click();
        });

after click it alerts me command argument. But on next step - when i trigger btn1 click with jquery it goes to codebehind and command argument is empty. Can i pass somehow command argument with jquery?

I've tried to save value to global variables but after postback they're all empty. And i don't want to use cookies or viewstate for that.

Thanks!

Answer 1

CommandArgument is completely a server-side property and doesn't render any html attribute. So you can't change any button's attribute and fire click on it. The good news is that you can fire postback with client-side __doPostBack function and pass your custom value as second parameter:

<script type="text/javascript">
    $("a").click(function () {
        var val = $(this).attr('id').toString();
        __doPostBack("<%= btn1.UniqueID %>", val);
    });
</script>

And you can get passed argument in server click handler from the Request.Form collection:

protected void button_click(object sender, EventArgs e)
{
    var argument = Request.Form["__EVENTARGUMENT"];
}

If script above won't work then maybe __doPostBack function not defined on page. In this case add this code to Page_PreRender method: ClientScript.GetPostBackEventReference(btn1, string.Empty); this will force page to define __doPostBack method on page.

Answer 2

I find using __doPostBack('id','args') creates a full page postback when on a submit button. I find it easier is add a hiddenfield the page, set the value, then call the button.click() event

    <asp:Button ID="btnTrigger" runat="server" ClientIDMode="Static" OnClick="btnTrigger_Click" />
    <asp:HiddenField ID="CommandArg" runat="server" ClientIDMode="Static" />


    $('#CommandArg').val('my argument');
    $('#btnTrigger').click();