Forms Data Controls :: Displaying Totals For Columns In A Grid View?

I have developed my application using ASP.NET with Visual Basic. I have a table that contains 3 fields. The name of the table is "Customer" and the names of the fields are "Name", "Address", and "Amount". I have a gridview that displays these three columns. I want to summarize the value in the "Amount" column for each record and display the summarize value in the footer of the "Amount" column.

I added some code to the "ItemTemplate" and "FooterTemplate" of the template for the "Amount" field and wrote two functions One function adds the value of the "Amount" field to a variable called "TotalAmount" and the second function 'gets' the value stored in the "TotalAmount" variable.

I am not getting any error messages and all of the items are displayed in the gridview but I am not displaying anything at the bottom of the "Amount" column. What more do I need to do?

This is my code for the "Amount" template:

<asp:TemplateField
HeaderText="Amount"
SortExpression="Amount">
<EditItemTemplate>
<asp:TextBox
ID="TextBox1"
runat="server"
Text='<%# Bind("Amount") %>'></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label
ID="Label1"
runat="server"
Text='<%# Bind("Amount", "{0:c}") %>'>
<%#SumAmount(Eval("Amount")) %></asp:Label>
</ItemTemplate>
<FooterTemplate>
<%#GetTotalAmount() %></FooterTemplate>
<FooterStyle
BorderColor="Black"
BorderStyle="Solid"
/>
</asp:TemplateField>
This is the code in my .vp file
Dim TotalAmount as decimal 0.0
Function SumAmount(ByVal Amount
As
Decimal)
As
Decimal
TotalAmount = TotalAmount + TotalAmount
End
Function
Function GetTotalAmount()
As
Decimal
Return TotalAmount
End
Function