Protected Overrides Sub OnPaintBackground(ByVal e As System.Windows.Forms.PaintEventArgs)
        MyBase.OnPaintBackground(e)
        Dim p As New Pen(Color.Red, 10)
        e.Graphics.DrawRectangle(p, e.ClipRectangle.X, e.ClipRectangle.Y, e.ClipRectangle.Width - 1, e.ClipRectangle.Height - 1)

    End Sub

this.Padding = new Padding(this.m_BorderWidth, this.m_BorderWidth + this.m_CaptionHeight, this.m_BorderWidth, this.m_BorderWidth);

------解决方案--------------------
C# code
 [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int wndproc);
        [System.Runtime.InteropServices.DllImport("user32.dll")]
        public static extern int GetWindowLong(IntPtr hWnd, int nIndex);

        public const int WS_CAPTION = 0xC00000;

        public const int GWL_STYLE = -16;


        private void Form1_Load(object sender, EventArgs e)
        {
            this.FormBorderStyle = FormBorderStyle.Sizable;
            SetWindowLong(this.Handle, GWL_STYLE, (~WS_CAPTION) & GetWindowLong(this.Handle, GWL_STYLE));
            this.Height = this.ClientSize.Height;
        }

------解决方案--------------------
觉得这需要细细调整，不是一两个技巧几句话就可以做成完好外观的。楼主好好再研究一下吧，我相信楼主会做出来好的效果的。