Visual Basic

class Program
{
    static void Main(string[] args)
    {
        using (var f = new Form())
        {
            var dgv = new DataGridView() { Dock = DockStyle.Fill };
            dgv.Columns.Add(new DataGridViewTextBoxColumn());
            dgv.CellPainting += dgv_CellPainting;
            for (int i = 0; i < 5; i++)
                dgv.Rows.Add(new[] { Guid.NewGuid().ToString() });
            f.Controls.Add(dgv);
            f.ShowDialog();
        }
    }

    static readonly Size rectSize = new Size(10, 10);

    static void dgv_CellPainting(
        object sender,
        DataGridViewCellPaintingEventArgs e)
    {
        e.Handled = false;

        if (0 == e.ColumnIndex)
        {
            if (-1 == e.RowIndex)
                return; // don't paint the title as if it were data

            e.PaintBackground(
                e.CellBounds,
                DataGridViewElementStates.Selected == e.State);

            e.PaintContent(e.ClipBounds);

            e.Graphics.FillRectangle(
                Brushes.Red,
                new Rectangle(e.CellBounds.Location, rectSize));

            e.Handled = true;
        }
    }
}

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]

Shared ReadOnly rectSize As New Size(10, 10)

   Private Shared Sub dgv_CellPainting(sender As Object, e As DataGridViewCellPaintingEventArgs)
       e.Handled = False

       If 0 = e.ColumnIndex Then
           If -1 = e.RowIndex Then
               Return
           End If

           e.PaintBackground(e.CellBounds, DataGridViewElementStates.Selected = e.State)

           e.PaintContent(e.ClipBounds)

           e.Graphics.FillRectangle(Brushes.Red, New Rectangle(e.CellBounds.Location, rectSize))

           e.Handled = True
       End If
   End Sub

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]

e.Handled = False

      If 0 = e.ColumnIndex Then
          If -1 = e.RowIndex Then
              Return
          End If

          e.PaintBackground(e.CellBounds, DataGridViewElementStates.Selected = e.State)

          e.PaintContent(e.ClipBounds)

          Dim x1 As Integer = e.CellBounds.Right
          Dim y1 As Integer = e.CellBounds.Top

          Dim x2 As Integer = x1 - 7
          Dim y2 As Integer = y1

          Dim y3 As Integer = y1 + 7
          Dim x3 As Integer = x1



          e.Graphics.FillPolygon(Brushes.Red, {New Point(x1, y1), New Point(x2, y2), New Point(x3, y3)})
          '  e.Graphics.FillRectangle(Brushes.Red, New Rectangle(e.CellBounds.Location, rectSize))

          e.Handled = True
      End If

Helium99 wrote:

How do is set which column the shape is in

If 0 = e.ColumnIndex Then

Helium99 wrote:

when clicked the text forecolor changes to white (until released). Can that
forecolor not change

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]

Dim port as string
Dim device as string

Try
Using searcher As New ManagementObjectSearcher("root\CIMV2", "SELECT * FROM Win32_SerialPort")

For Each queryObj As ManagementObject In searcher.Get()
port = queryObj("DeviceID")
device = queryObj("Description")
Next
End Using
Catch err As ManagementException
MessageBox.Show("An error occurred while querying for WMI data: " & err.Message)
End Try

SepPax wrote:

something more advanced to suggest?

SepPax wrote:

something more advanced to suggest?

Dim out As Byte() = New Byte(7) {}