Need help to sum

[XXD]

Hi

On my form there is some prices showing from a query, how can i make a "total price". Sum up all the prices in one texbox?
I have attached a image to make it clearly

=Sum([Total price]) isn't working
any suggestions?

Thanks in advance
XXD

Edit: Found the problem
wrote the code in the EventProcedur the code need to be on the Data xD

 

[Pat Hartman]

Your expression is correct as long as [Total Price] is the name of the bound field and the control is in the form's footer section.