文本框自定义onPaint

Question

我正在尝试为我的文本框创建自定义的onPaint，它正在工作... it is working但是，当我尝试输入内容时，a textbox is rendering above the textbox。

这是我的构造函数：

public TextBox() 
{ 
    Font = new Font("Segoe UI", 11F, FontStyle.Regular, GraphicsUnit.Point, ((byte)(0))); 
    BackColor = Color.White; 
    BorderColor = Color.Gray; 
    BorderStyle = BorderStyle.None; 
    SetStyle(ControlStyles.UserPaint, true); 
} 

而且OnPaint中：

protected override void OnPaint(PaintEventArgs e) 
{ 
    Graphics g = e.Graphics; 
    g.FillRectangle(backgroundBrush, 0, 0, this.Width, this.Height); 

    SizeF fontSize = g.MeasureString(Text, Font); 
    g.DrawString(Text, Font, new SolidBrush(ForeColor), new PointF(5, 5), cFormat); 

    g.DrawRectangle(borderPen, borderPen.Width/2, borderPen.Width/2, 
        this.Width - borderPen.Width, this.Height - borderPen.Width); 
} 

Answer 1

如果你只是想自定义TextBox一些自定义的边框（宽度和颜色），我有2个解决方案，在这里：

1. 使用ControlPaint，这将让你博士AW边境的一些样式和颜色，但不能用Brush吸引更多的不同（如HatchBrush可以做）：

   public class CustomTextBox : TextBox 
   { 
       [DllImport("user32")] 
       private static extern IntPtr GetWindowDC(IntPtr hwnd); 
       struct RECT 
       { 
        public int left, top, right, bottom; 
       } 
       struct NCCALSIZE_PARAMS 
       { 
        public RECT newWindow; 
        public RECT oldWindow; 
        public RECT clientWindow; 
        IntPtr windowPos; 
       }    
       float clientPadding = 2; 
       float actualBorderWidth = 4; 
       Color borderColor = Color.Red;  
       protected override void WndProc(ref Message m) 
       { 
        //We have to change the clientsize to make room for borders 
        //if not, the border is limited in how thick it is. 
        if (m.Msg == 0x83) //WM_NCCALCSIZE 
        { 
        if (m.WParam == IntPtr.Zero) 
        { 
         RECT rect = (RECT)Marshal.PtrToStructure(m.LParam, typeof(RECT)); 
         rect.left += clientPadding; 
         rect.right -= clientPadding; 
         rect.top += clientPadding; 
         rect.bottom -= clientPadding; 
         Marshal.StructureToPtr(rect, m.LParam, false); 
        } 
        else 
        { 
         NCCALSIZE_PARAMS rects = (NCCALSIZE_PARAMS)Marshal.PtrToStructure(m.LParam, typeof(NCCALSIZE_PARAMS)); 
         rects.newWindow.left += clientPadding; 
         rects.newWindow.right -= clientPadding; 
         rects.newWindow.top += clientPadding; 
         rects.newWindow.bottom -= clientPadding; 
         Marshal.StructureToPtr(rects, m.LParam, false); 
        } 
        } 
        if (m.Msg == 0x85) //WM_NCPAINT  
        {   
        IntPtr wDC = GetWindowDC(Handle); 
        using(Graphics g = Graphics.FromHdc(wDC)){              
         ControlPaint.DrawBorder(g, new Rectangle(0,0,Size.Width, Size.Height), borderColor, actualBorderWidth, ButtonBorderStyle.Solid, 
        borderColor, actualBorderWidth, ButtonBorderStyle.Solid, borderColor, actualBorderWidth, ButtonBorderStyle.Solid, 
        borderColor, actualBorderWidth, ButtonBorderStyle.Solid); 
        } 
        return;   
        } 
        base.WndProc(ref m); 
       } 
   } 
   

   这里是文本框快照：使用FillRegion

   

2. 方法Graphics用各种Brush来绘制边框，这里我用HatchBrush：

   public class CustomTextBox : TextBox 
   { 
       [DllImport("user32")] 
       private static extern IntPtr GetWindowDC(IntPtr hwnd); 
       struct RECT 
       { 
       public int left, top, right, bottom; 
       } 
       struct NCCALSIZE_PARAMS 
       { 
       public RECT newWindow; 
       public RECT oldWindow; 
       public RECT clientWindow; 
       IntPtr windowPos; 
       }   
       int clientPadding = 2; 
       int actualBorderWidth = 4;  
       protected override void WndProc(ref Message m) 
       { 
        //We have to change the clientsize to make room for borders 
        //if not, the border is limited in how thick it is. 
        if (m.Msg == 0x83) //WM_NCCALCSIZE 
        { 
        if (m.WParam == IntPtr.Zero) 
        { 
         RECT rect = (RECT)Marshal.PtrToStructure(m.LParam, typeof(RECT)); 
         rect.left += clientPadding; 
         rect.right -= clientPadding; 
         rect.top += clientPadding; 
         rect.bottom -= clientPadding; 
         Marshal.StructureToPtr(rect, m.LParam, false); 
        } 
        else 
        { 
         NCCALSIZE_PARAMS rects = (NCCALSIZE_PARAMS)Marshal.PtrToStructure(m.LParam, typeof(NCCALSIZE_PARAMS)); 
         rects.newWindow.left += clientPadding; 
         rects.newWindow.right -= clientPadding; 
         rects.newWindow.top += clientPadding; 
         rects.newWindow.bottom -= clientPadding; 
         Marshal.StructureToPtr(rects, m.LParam, false); 
        } 
        } 
        if (m.Msg == 0x85) //WM_NCPAINT 
        {     
        IntPtr wDC = GetWindowDC(Handle); 
        using(Graphics g = Graphics.FromHdc(wDC)){             
         Rectangle rect = new Rectangle(0,0,Width,Height); 
         Rectangle inner = new Rectangle(0, 0, Width, Height); 
         inner.Offset(actualBorderWidth + 2, actualBorderWidth + 2); 
         inner.Width -= 2 * actualBorderWidth + 4; 
         inner.Height -= 2 * actualBorderWidth + 4; 
         Region r = new Region(rect); 
         r.Xor(inner); 
         using (System.Drawing.Drawing2D.HatchBrush brush = new System.Drawing.Drawing2D.HatchBrush(System.Drawing.Drawing2D.HatchStyle.SmallCheckerBoard, Color.Green, Color.Red)) 
         {      
         g.FillRegion(brush, r); 
         } 
        } 
        return; 
        } 
        base.WndProc(ref m); 
       } 
   } 
   

   这里是文本框快照：