绘制束线到Visualbasic Picturebox

Question

我在datagridview中有数千个x和y坐标，我需要用它们绘制线条。例如，第1行，单元格1包含x，第1行单元格2包含y并继续。我需要从第1行到第2行，第2行到第3行。必须像设计一样。我使用For i = 1到1000。我用了画线功能。

 Dim bmp As New Drawing.Bitmap(640, 480)
 Dim gfx As Graphics = Graphics.FromImage(bmp)
 Dim i As Integer
 Dim prcoordx As Integer
 Dim prcoordy As Integer
 Dim nextcoordx As Integer
 Dim nextcoordy As Integer   
 For i = 1 To 1000 Step 1
                prcoordx = DataGridView1.Rows(i).Cells(1).Value
                prcoordy = DataGridView1.Rows(i).Cells(2).Value
                nextcoordx = DataGridView1.Rows(i+1).Cells(1).Value
                nextcoordy = DataGridView1.Rows(i+1).Cells(2).Value

   Next i

   gfx.DrawLine(Pens.Black, prcoordx, prcoordy, nextcoordx, nextcoordy)