[عبد العزيز البسكري]

جرب هذا ..

كود :

   Private Sub DataGridView1_CellPainting(sender As Object, e As DataGridViewCellPaintingEventArgs) Handles DataGridView1.CellPainting
       If e.RowIndex = -1 AndAlso e.ColumnIndex >= 0 Then
           e.PaintBackground(e.ClipBounds, True)
           Dim rect As Rectangle = Me.dataGridView1.GetColumnDisplayRectangle(e.ColumnIndex, True)
           Dim titleSize As Size = TextRenderer.MeasureText(e.Value.ToString(), e.CellStyle.Font)
           If Me.DataGridView1.ColumnHeadersHeight < titleSize.Width Then
               Me.DataGridView1.ColumnHeadersHeight = titleSize.Width
           End If
           e.Graphics.TranslateTransform(0, titleSize.Width)
           e.Graphics.RotateTransform(-90.0F)
           e.Graphics.DrawString(e.Value.ToString(), Me.Font, Brushes.Black, New PointF(rect.Y - (dataGridView1.ColumnHeadersHeight - titleSize.Width), rect.X))
           e.Graphics.RotateTransform(90.0F)
           e.Graphics.TranslateTransform(0, -titleSize.Width)
           e.Handled = True
       End If
   End Sub

ثم بالفورم لود بعد تحميل البيانات ..

كود :

     Me.DataGridView1.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.EnableResizing
       Me.DataGridView1.ColumnHeadersHeight = 50
       Me.DataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCellsExceptHeader

       AddHandler DataGridView1.CellPainting, AddressOf DataGridView1_CellPainting