Jon's Blog

So I was working on a project where I needed to have some checkboxes in a GridView. When checked they needed to update the underlying business object. My first idea was the just wrap the whole thing in an UpdatePanel, but that would of course require a partial postback with the full contents of the grid being posted back to the server. The better solution is to call a web service method to do the update.

First, add a new Web Service class to your project. You need to add the [ScriptService] attribute to this class. This attribute is from the System.Web.Script.Services namespace. Then create your WebMethod, including whatever parameters you will need to pass in.

[WebMethod]
public void UpdateFlag(int id, bool isChecked)
{
    // Logic to update business object
}

Next you need to add a ServiceReference that points to the web service you just created. You can add this to your ScriptManager instance. In my scenario the ScriptManager was in the Master page and I just wanted to include the ServiceReference in this one ASPX page. Here you can use the ScripManagerProxy object like so (assuming the WebService file is in the same directory as the ASPX file):

<asp:ScriptManagerProxy ID="scriptManProxy" runat="server">
    <Services>
        <asp:ServiceReference Path="MyWebService.asmx" />
    </Services>
</asp:ScriptManagerProxy>

Then add the following code to your GridView's RowDataBound event. This will set the onclick events for the individual checkboxes you are binding to the GridView.

if (e.Row.RowType == DataControlRowType.DataRow)
{
    BusinessObject obj = (BusinessObject)e.Row.DataItem;
    CheckBox myCB = (CheckBox)e.Row.FindControl("myCB");

    string eventText = string.Format("myCB_Checked({0}, this);", obj.SomeID);
    myCB.Attributes["onclick"] = eventText;
}

Now you need to actually write the JavaScript method that will call your web service. Here it is:

<script type="text/javascript">
    function myCB_Checked(id, ctrl) {
        var isChecked = ctrl.checked;
        Namespace.MyWebService.UpdateFlag(id, isChecked);
    }
</script>

Make sure that you use the fully qualified name of your class here.

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