Question

I have a GridView with each row containing a checkbox, and the header of that column is a checkbox with checkAll functionality:

<Columns>
     <asp:TemplateField>
            <HeaderTemplate>
                   <input id="chkAll" onclick="javascript:SelectAllCheckboxes(this);"                                       runat="server" type="checkbox" />
            </HeaderTemplate>
            <ItemTemplate>
                   <asp:CheckBox ID="chkSelect" runat="server" ToolTip="Select this order" AutoPostBack="true" OnCheckedChanged="chkSelect_OnCheckedChanged"/>
            </ItemTemplate>
     </asp:TemplateField>
     ...More BoundFields
</Columns>

The javascript behind the SelectAllCheckboxes()

function SelectAllCheckboxes(spanChk) {

        // Added as ASPX uses SPAN for checkbox

        var oItem = spanChk.children;
        var theBox = (spanChk.type == "checkbox") ?
    spanChk : spanChk.children.item[0];
        xState = theBox.checked;
        elm = theBox.form.elements;

        for (i = 0; i < elm.length; i++)
            if (elm[i].type == "checkbox" &&
          elm[i].id != theBox.id) {
                //elm[i].click();

                if (elm[i].checked != xState)
                    elm[i].click();
                //elm[i].checked=xState;

            }
    }

My GridView basically contains sales (orders) from my website, so dollar amounts. The OnCheckedChanged event adds (if checked) or subtracts (if unchecked) the current row’s price from a totalAmount that is displayed on the page.
This all works great except that when I click the checkAll checkbox, all of the OnCheckedChanged events for all of the row check boxes fire and it takes a long time to process it all. Since all that I am doing in the OnCheckedChanged method is summing amounts, is there a way that I can NOT call the events for the individual checkboxes and just make one call to a separate method that will grab all the GridView rows and sum them all at once?

Answer 1

If you consider doing it all on the server in one postback, you could try this:

<Columns>
    <asp:TemplateField>
         <HeaderTemplate>
              <asp:CheckBox ID="chkAll" runat="server" ToolTip="Select this order" AutoPostBack="true" OnCheckedChanged="chkAll_OnCheckedChanged"/>
         </HeaderTemplate>
         <ItemTemplate>
              <asp:CheckBox ID="chkSelect" runat="server" ToolTip="Select this order" AutoPostBack="true" OnCheckedChanged="chkSelect_OnCheckedChanged"/>
         </ItemTemplate>
    </asp:TemplateField>
</Columns>

On the code behind:

    protected void chkSelect_OnCheckedChanged(object sender, EventArgs e)
    { 
        //Process checked item 
    }

    protected void chkAll_OnCheckedChanged(object sender, EventArgs e)
    {
        foreach (GridViewRow item in grdTest.Rows)
        {
            CheckBox ckb = (CheckBox)item.FindControl("chkSelect");

            //This will not call the individual event
            ckb.Checked = ((CheckBox)sender).Checked;
            //Process checked item 
        }
    }