Rowvalidating e cancel
You can extend the Data Grid View control in a number of ways to build custom behaviors into your applications.
For example, you might want to have a routine that fires on the form's “Closing” event or a data save method to loop through all the controls on your form and validate them independently to ensure that all controls are valid. If you see the code, it's already listening to the ESC key.This should be simple, but I can't seem to figure it out. I don't know how to go about getting it to remember if it has seen the value before. Value) Next Next End Sub As you can probably work out, all I've managed to do is cycle through each cell in the first column and display a msgbox with the value. I need my program to check for duplicate values in one particular column in my Data Grid View prior to saving the data but I don't really know how to start.. Click Dim R As Integer Dim C As Integer For R = 0 To (Data Grid View1. This will allow you to keep track of what row you are on (so you don't get self duplicates. Had to make a tweak or two (no criticism there at all! Note: Your code started at row 1 then checked rows 1 to end. I tweaked so that the inside loop started on the following row instead of from 1 again (this was causing the loop to think the very first value was a duplicate.
Thanks John Private Sub Button1_Click(By Val sender As System.
Please assist me on this [email protected]: I did not realize that you had this code in the Row Validating event handler.
provides a convenient way to realize data validation before it is committed to the underlying data source.
Thanks again John I'm assuming you need to check each value against each other value, in which case you are going to need 2 for loops, and normally I would say as For Each, but for what you need you should do a For int I to rows.count. Count - 2 For int J As Integer = int I 1 To Data Grid View1.
As soon as it sees a duplicate value, it should end the loop and display warning.
This might be a common scenario in data entry forms where you might create a new record and the user might not touch all the fields on your form (and thus never trigger the “Validating” event of your controls). One, pointed out by Chris Sells (read more), invokes the Control's “Notify Validating” event through Reflection.