If the cell has to be checked for both the conditions try the following code:
If (e.ColumnIndex = 0) Then
Dim cellData As Integer
IF Not DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value is DBNull.Value Then
If (Int32.TryParse(DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value, cellData)) Then
If cellData < 0 Then
MessageBox.Show("Negative Numbers Not Allowed")
DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value = "Name"
Exit Sub
End If
End If
If (String.IsNullOrEmpty(DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value)) Then
MessageBox.Show("Cannot Be Empty")
DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value = "Name"
Exit Sub
End If
Else
MessageBox.Show("Cannot Be Empty")
DataGridView1.Rows(e.RowIndex).Cells(e.ColumnIndex).Value = "Name"
Exit Sub
End If
End If