Removing duplicate data out of column datagridview vb.net

Question

I've looked all around and haven't found a answer :/

screenshot: http://prntscr.com/9257cg

I want that entry to only show up once and not stay there (the "to" column), basically remove the duplicates. Here is my update code

Private Sub datagridview1Update()

    'Remove rows if there are too many
    If DataGridView1.Rows.Count > 9 Then
        DataGridView1.Rows.RemoveAt(0)
    End If

    DataGridView1.Rows.Add()
    DataGridView1.Rows(DataGridView1.Rows.Count - 2).Cells(0).Value = ipfrom.ToString 'From Column, size at 125
    DataGridView1.Rows(DataGridView1.Rows.Count - 2).Cells(1).Value = ipto.ToString  'To Column, size at 125
    DataGridView1.Rows(DataGridView1.Rows.Count - 2).Cells(2).Value = destinationport.ToString
    DataGridView1.Rows(DataGridView1.Rows.Count - 2).Cells(3).Value = sourceport.ToString

End Sub

Answer 1

First you should loop through your DataGridView1's Rows to see if there is already an entry that matches the new data. Add the new row if no match is found. Also, you should only subtract one from the count of rows to keep correct ordering.

Private Sub datagridview1Update()

    Dim bolFoundMatch As Boolean = False
    Dim intCursor As Integer = 0

    Do Until bolFoundMatch OrElse intCursor = DataGridView1.Rows.Count

        If DataGridView1.Rows(intCursor).Cells(1).Value = ipto.ToString() Then

            bolFoundMatch = True

        End If

        intCursor += 1

    Loop

    If Not bolFoundMatch Then

        'Remove rows if there are too many
        If DataGridView1.Rows.Count > 9 Then
            DataGridView1.Rows.RemoveAt(0)
        End If

        DataGridView1.Rows.Add()
        DataGridView1.Rows(DataGridView1.Rows.Count - 1).Cells(0).Value = ipfrom.ToString 'From Column, size at 125
        DataGridView1.Rows(DataGridView1.Rows.Count - 1).Cells(1).Value = ipto.ToString  'To Column, size at 125
        DataGridView1.Rows(DataGridView1.Rows.Count - 1).Cells(2).Value = destinationport.ToString
        DataGridView1.Rows(DataGridView1.Rows.Count - 1).Cells(3).Value = sourceport.ToString   

    End If

End Sub