C# TextBox增加Padding屬性，或者TextBox垂直居中

 public partial class PubTextBox : TextBox     {         //设置Rect消息         private const int EM_SETRECT = 179;         //获取Rect消息         private const int EM_GETRECT = 178;         //粘贴消息         private const int WM_PASTE = 0x0302;         public PubTextBox()         {             InitializeComponent();                      }         protected override void OnResize(EventArgs e)         {             base.OnResize(e);             SetTextDispLayout();         }         protected override void OnTextAlignChanged(EventArgs e)         {             base.OnTextAlignChanged(e);             SetTextDispLayout();         }         protected override void OnKeyPress(KeyPressEventArgs e)         {             //如果不允许回车 屏蔽回车 换行键值             if (!AllowReturn                 && ((int)e.KeyChar == (int)Keys.Return || (int)e.KeyChar == (int)Keys.LineFeed))             {                 e.Handled = true;             }             base.OnKeyPress(e);         }         /// <summary>         /// 窗体处理消息主函数 处理粘贴及绘制消息         /// </summary>         /// <param name="m"></param>         protected override void WndProc(ref System.Windows.Forms.Message m)         {             string str = "";             bool flag = false;             int i = 0;             if (m.Msg == 0x0204)                 i++;             if (!AllowReturn                 && m.Msg == WM_PASTE                 && System.Windows.Forms.Clipboard.ContainsText())             {                 str = System.Windows.Forms.Clipboard.GetText();                 System.Windows.Forms.Clipboard.Clear();                 string nstr = str.Replace(char.ConvertFromUtf32((int)Keys.Return), "").Replace(char.ConvertFromUtf32((int)Keys.LineFeed), "");                 System.Windows.Forms.Clipboard.SetText(nstr);                 if (str.Length > 0) flag = true;             }             base.WndProc(ref m);             if (flag)             {                 flag = false;                 System.Windows.Forms.Clipboard.SetText(str);                 str = "";             }                    }         [DllImport("user32.dll", EntryPoint = "SendMessageA")]         private static extern int SendMessage(IntPtr hwnd, int wMsg, IntPtr wParam, string lParam);         [DllImport("user32.dll", EntryPoint = "SendMessageA")]         private static extern int SendMessage(IntPtr hwnd, int wMsg, IntPtr wParam, ref Rectangle lParam);         /// <summary>         /// 尺寸变化时重新设置字体的显示位置居中         /// </summary>         /// <param name="e"></param>         protected override void OnSizeChanged(EventArgs e)         {             base.OnSizeChanged(e);             SetTextDispLayout();         }         /// <summary>         /// 设置文本显示布局位置         /// </summary>         public void SetTextDispLayout()         {             if (Text == "")                 return;             //當允許多行和禁止回車時，Paddin有效             if (this.Multiline && (!this.WordWrap))             {                 Rectangle rect = new Rectangle();                 SendMessage(this.Handle, EM_GETRECT, (IntPtr)0, ref rect);                 //SizeF size = CreateGraphics().MeasureString(Text, Font);//垂直居中 計算文本高度                 //rect.Y = (int)(Height - size.Height) / 2 + TextPadding.Top;                 rect.Y = TextPadding.Top;                 rect.X = TextPadding.Left;                 rect.Height = Height;                 rect.Width = Width - TextPadding.Right - TextPadding.Left;                 SendMessage(this.Handle, EM_SETRECT, IntPtr.Zero, ref rect);             }         }             /// <summary>         /// 是否允许有回车         /// </summary>         [CategoryAttribute("設定"), DisplayName("允許回車"), DescriptionAttribute("配合內邊使用")]         public bool AllowReturn { get; set; }         protected override void OnTextChanged(EventArgs e)         {             base.OnTextChanged(e);             SetTextDispLayout();         }         private Padding _textpadding=new Padding(1);         /// <summary>         /// Text Padding值  當允許多行和禁止回車時，Paddin有效         /// </summary>         [CategoryAttribute("設定"), DisplayName("內邊距"), DescriptionAttribute(" 當允許多行和禁止回車時，Paddin有效")]

        public Padding TextPadding { get { return _textpadding; } set { _textpadding = value; SetTextDispLayout(); } }

    }

參考：http://www.cnblogs.com/jason_chen/p/6291295.html