DataGridView row delete

Question

Hi,

I have created a Windows Form app in Visual Basic with a DataGridView to allow the user to enter rows of information in table form. I added a delete row button and use the below code to delete rows from the data grid view. It works perfectly, except if I accidentally press the delete button when the blank row automatically added to the bottom of the DataGridView. I get a system NullReference exception as per the snapshot below.

Does anyone have better code for the button or a code to bring up a message box telling the user not to delete the bottom row then return to the app.

Dim rowIndex As Integer = DataGridView1.CurrentCell.RowIndex
If rowIndex >= 0 AndAlso rowIndex < DataGridView1.Rows.Count - 1 Then
      DataGridView1.Rows.RemoveAt(rowIndex)
End If

Answer 1

@SeanPress, Welcome to Microsoft Q&A, based on your description, you want to handle the NullReference exception when you remove the bottom row.

I recommend that you could check if the DataGridviewCell is nothing first.

Here is a code example you could refer to.

 Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
     Dim currentcell As DataGridViewCell = DataGridView1.CurrentCell
     If currentcell IsNot Nothing Then
         Dim rowIndex As Integer = DataGridView1.CurrentCell.RowIndex
         If rowIndex >= 0 AndAlso rowIndex < DataGridView1.Rows.Count - 1 Then
             DataGridView1.Rows.RemoveAt(rowIndex)
         End If
     Else
         MessageBox.Show("please don't remove the bottom row")
     End If
 End Sub

Then, when you remove the bottom row, you will get the message box to tell you that please don't remove the bottom row.

Tested result:

Hope it could help you.

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