How to delete empty datagridview cells on import - vb.net

Question

Currently I have my program hiding blank or empty datagridview cells. I want to find a way to delete these cells entirely. The reason being, after the blank cells were hidden they would reappear after going through some of my other validations. These validations checked to see if the cells contained any invalid input such as negative numbers,non-numeric input and blank cells. If they contained any of the above they would be populated with default values, thus making my hidden cells reappear. Hopefully if there is a way to delete these cells they won't have a change of getting filled with default data. I've found the below code on MSDN but it doens't seem to work properly for whatever reason. Also I'm using the DATABINDINGCOMPLETE event. I'm not sure if there is another event that would work better for this situation. I greatly appreciate any help you may give!
Private Sub DataGridView1_DataBindingComplete(sender As Object, e As DataGridViewBindingCompleteEventArgs) Handles DataGridView1.DataBindingComplete
Dim i As Integer = 0
Dim mtCell As Integer = 0
For Each row As DataGridViewRow In DataGridView1.Rows
For j = 1 To row.Cells.Count -2
If row.Cells(j).Value Is DBNull.Value Then
mtCell += 1
End If
Next
If mtCell = row.Cells.Count Then
DataGridView1.Rows.RemoveAt(i)
End If
i += 1
mtCell = 0
Next
end sub

Answer 1

There are various problems with your code. Here you have an improved version which should work without any problem:
Dim mtCell As Integer = 0
Dim row As DataGridViewRow = New DataGridViewRow()
For rowNo As Integer = DataGridView1.Rows.Count - 2 To 0 Step -1
row = DataGridView1.Rows(rowNo)
Try
For j = 0 To row.Cells.Count - 2
If row.Cells(j).Value Is Nothing OrElse row.Cells(j).Value Is DBNull.Value Then
mtCell += 1
End If
Next
If mtCell = row.Cells.Count - 1 Then 'I understand that you want to delete the row ONLY if all its cells are null
DataGridView1.Rows.RemoveAt(rowNo)
End If
mtCell = 0
Catch ex As Exception
Exit For
End Try
Next rowNo
First thing, it is better to iterate the Collection "backwards" when deleting in order to avoid problems (example: 3 rows; you delete the first position and the loop goes to the second one; but after the deletion all the rows "move up" and thus the second position is now occupied by the third row -> you would skip the second row and, eventually, iterate beyond the limits of the Collection). DBNull.Value is quite restrictive; not sure if it is working fine under your specific conditions, but better complementing it with Nothing. You cannot affect the item being iterated in a For Each loop (unlikely in a normal For one); in this case you are affecting it indirectly but just to make sure, better relying on a normal For loop. You are iterating through rows but you are not deleting these rows, but the ones defined by a counter (i) which is not necessarily related to the current row number, better getting rid of it. Lastly I have included a try...catch to make sure (that you don't access an inexistent position).