文本框自定义onPaint

Question

I'm trying to create a custom onPaint for my textbox, it is working... it is working But when I try to type something, a textbox is rendering above the textbox .

This is my constructor:

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);
}

And the onPaint:

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

If you just want a custom TextBox with some custom border (width and color), I have 2 solutions here:

1. Using ControlPaint , this will allow you to draw border with some style and color but can't use Brush to draw more variously (like a HatchBrush can do):

    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); } } 

   Here is the textbox snapshot:

   

2. using FillRegion method of a Graphics to paint the border with various kinds of Brush , here I use 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); } } 

   Here is the textbox snapshot: