calling server side c# from <input> element in repeater - asp.net

Question

<td><input type="image" style="border-width:0" alt="Do an Edit" title="Edit the repeater row" tabindex="0" src='<%=ResolveUrl("~/css/image.png") %>' onclick='showModal(<%#Container.ItemIndex %>); return false;'/></td>
I am already using onClick() for invoking a javascript method. Now, I want to add another an event to this element to trigger a server side event- say using onKeyUp- and pass 1 parameter on the repeater to the server side.
Is this possible or I have to first call javaScript and then Javascript on the page will callinto my server side. (I think this way the method in the server side code has to be static).

Answer 1

You can add an invisible LinkButton to your page (for example LinkButton with a blank text) and from your client-side onKeyUp event call LinkButton's click() method and catch Click event server side.
To pass parameter you can use any control that is readable both client-side and server side, for example hidden field.
For example - your HTML markup can look something like this:
<asp:TextBox ID="xtxtMyText" runat="server" onkeyup="doMyPostback()"></asp:TextBox>
<asp:HiddenField ID="xhidParam" runat="server" />
<asp:LinkButton ID="xlnkMyPostBack" runat="server" OnClick="xlnkMyPostBack_Click"></asp:LinkButton>
<script type="text/javascript">
function doMyPostback(e) {
var evt = window.event ? window.event : e;
if (evt.keyCode == 13) {
document.getElementById('xhidParam').value = document.getElementById('xtxtMyText').value;
document.getElementById('xlnkMyPostBack').click()
}
}
</script>
Here you have a textbox that triggers keyUp event, hidden linkbutton that causes server-side Click event and hidden field that is used to pass parameter. In this scenario if user hits Enter, content of textbox is copied to the hidden variable and the linkbutton is clicked.
On the server side you can handle that event and read the passed parameter from the hidden field, e.g.
protected void xlnkMyPostBack_Click(object sender, System.EventArgs e)
{
Response.Write(xhidParam.Value);
}