图片随窗体一起变化 程序调不通

[TaohuachiDaxia]

各位大神：
我编了一段程序，目的就是让图片框内的图片在窗体最大化时可以随图片框共同变化。但总遇到这样一个问题。
错误提示为：“未将对象引用设置到对象的实例”
求大神指正。测试程序如下：

Public Class Form1
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim g As Graphics = PictureBox1.CreateGraphics
Me.Width = 500
Me.Height = 400
PictureBox1.Width = 400
PictureBox1.Height = 300
Dim oldpic As Bitmap = Image.FromFile("d:\小熊.bmp")
‘拉伸图片将图片框填满
Dim PicNew As Bitmap = New System.Drawing.Bitmap(oldpic, Me.PictureBox1.Width, Me.PictureBox1.Height)
PictureBox1.Image = PicNew
End Sub

’窗体最大化时，希望重新载入图片，并同样将图片框填满
Private Sub Form1_Resize(sender As Object, e As EventArgs) Handles Me.Resize
PictureBox1.Width = Me.Width - 100
PictureBox1.Height = Me.Height - 100
Dim mybmp As Bitmap = New System.Drawing.Bitmap(PictureBox1.Image)
Dim picNew As Bitmap = New System.Drawing.Bitmap(mybmp, Me.PictureBox1.Width, Me.PictureBox1.Height)
PictureBox1.Image = picNew
End Sub

End Class

[TaohuachiDaxia]

xdashewan ： 我有看到这个错误，问题是如何修改呐？ zj_zwl ： 我是程序其他部分需要用这个功能，所以不能修改你提到的地方。

[xdashewan]

报出错误的那行代码中有一个对象为NULL，你可以调试下

[exception92]

http://www.cnblogs.com/alexis/archive/2010/11/06/1870519.html 学会调试 才能更好的编程。

[zj_zwl]

不用写一行代码就可以实现你的功能,建议你看下picturebox控件的anchor和sizemode两个属性

[OneCoderr]

我觉得根本不需要写代码，设置picturebox的 dock为full，sizemode就可以了

[ckp00001]

图片随窗体变化而变化，建议在Sub OnPaint中做,例如：

    Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
        Dim G As Graphics = Me.CreateGraphics
                  G.DrawImage(PictureBox1, New Rectangle(PictureBox1.X, _
                                               PictureBox1Point.Y,PictureBox1Width, PictureBox1Height))
    End Sub
    Private Sub Form1_Resize(sender As Object, e As EventArgs) Handles Me.Resize
          Me.Refresh()
    End Sub