Question

I need to get a sum for all items in a column within a listview. I put in the following code in the itemdatabound event, but realized after testing it that it will only be getting what is bound, oops.

So I was looking for a little help converting this to show a total for my column from all items bound to the ListView.

Thanks.

 if (e.Item.ItemType == ListViewItemType.DataItem)     
       {
           ListViewDataItem item = (ListViewDataItem)e.Item;         

           Label lblQty = (Label)e.Item.FindControl("lblQuantity");
           if (lblQty == null)
           {
               return;
           }

           if (lblQty.Text.Length == 0 || lblQty.Text == "")
           {
               return;
           }
           else
           {
               ListViewTotal += int.Parse(lblQty.Text);
           }
       }

Answer 1

The best method I have found to do this is to implement the OnDataBinding method for the control you are binding. For example:

<asp:ListView ID="ListView1" runat="server">
    <ItemTemplate>
        <asp:Literal ID="yourLiteral" runat="server"
            OnDataBinding="yourLiteral_DataBinding"></asp:Literal>
    </ItemTemplate>
</asp:ListView>

First define a global counter in your .cs:

private int _quantityTotal = 0;

Then implement the OnDataBinding for the control:

 protected void yourLiteral_DataBinding(object sender, System.EventArgs e)
 {
     // You could get anything here to get a value including calling a DB
     // call if you want for each item that is being bound.
     Literal lt = (Literal)(sender);
     int quantity = (int)(Eval("yourQuantityField"));
     _quantityTotal += quantity;
     lt.Text = quantity.ToString();
 }

Now you have the total stored in _quantityTotal which you can then add to a footer or something else after the databinding has occurred like the OnDataBound event.