Paul Williams Paul Williams - 1 month ago 14
Vb.net Question

Validating DataGridView Cells

I have a datagridview on my form currently. The idea that I'm trying to do is to catch a possible double entry issue when a user edits a cell in the datagridview. I'm supposed to check the field for a duplicate value (which

CheckContestantList
already does by looping through each row and a possible match). On a match, the previous value is supposed to be restored and a messagebox should pop up and warn the user while resetting that field to edit mode.

However, when a user presses the Enter key... the current row indicator moves down by one... and throws everything off. I've already done a bit of reading on the matter but I can't seem to keep the current cell active even if someone presses Enter.

How do I allow for the Enter key to still confirm the enter press but not move down by one row?

Private Sub dgvContestantPool_CellEndEdit(sender As Object, e As DataGridViewCellEventArgs) Handles dgvContestantPool.CellEndEdit
' On the editing of the field, check to see if the value already exists.

If CheckContestantList(dgvContestantPool.CurrentCell.Value) = True Then

' Reset the value to the original value...
dgvContestantPool.ClearSelection()
dgvContestantPool.CurrentCell = dgvContestantPool.Rows(intCurrentRow).Cells("ContestantName")
dgvContestantPool.Rows(intCurrentRow).Selected = True

dgvContestantPool.CurrentCell.Value = strOldValue
dgvContestantPool.BeginEdit(True)

' Alert the user to try again...
MessageBox.Show("Entered value already exists in the list, try again or delete the entry.", "INVALID DATA - Already Exists", MessageBoxButtons.OK, MessageBoxIcon.Error)
Else
' Go ahead and let the edit persists.
End If

End Sub

Private Sub dgvContestantPool_CellBeginEdit(sender As Object, e As DataGridViewCellCancelEventArgs) Handles dgvContestantPool.CellBeginEdit
strOldValue = dgvContestantPool.CurrentCell.Value
intCurrentRow = dgvContestantPool.CurrentRow.Index

End Sub

Answer

You are using the wrong datagridview event, if you're gonna validate an input, you can use the _CellValidating event.

Here's an example:

 Private Sub dgvContestantPool_CellValidating(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellValidatingEventArgs) Handles dgvContestantPool.CellValidating
    If CheckContestantList(dgvContestantPool.Rows(e.RowIndex).Cells(e.ColumnIndex).EditedFormattedValue) = True Then
        'Your code goes here
    End If
 ...

Now, for example the cell value is invalid, you can call the e.Cancel = True in the cell_validating event so that the user cannot go to other cells unless the cell value is valid or press the ESC key. This will exit the cell and return to its previous/original value.

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