Change border color in TextBox C#

by

To change border color of TextBox you can override WndProc method and handle WM_NCPAINT message. Then get the window device context of the control using GetWindowDC because we want to draw to non-client area of control. Then to draw, it’s enough to create a Graphics object from that context, then draw border for control.

To redraw the control when the BorderColor property changes, you can use RedrawWindow method.

Code

Here is a TextBox which has a BorderColor property. The control uses BorderColor if the property values is different than Color.Transparent and BorderStyle is its default value Fixed3d.

using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;

public class MyTextBox : TextBox {
    const int WM_NCPAINT = 0x85;
    const uint RDW_INVALIDATE = 0x1;
    const uint RDW_IUPDATENOW = 0x100;
    const uint RDW_FRAME = 0x400;
    [DllImport("user32.dll")]
    static extern IntPtr GetWindowDC(IntPtr hWnd);
    [DllImport("user32.dll")]
    static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
    [DllImport("user32.dll")]
    static extern bool RedrawWindow(IntPtr hWnd, IntPtr lprc, IntPtr hrgn, uint flags);
    Color borderColor = Color.Blue;
    public Color BorderColor {
        get { return borderColor; }
        set { borderColor = value;
            RedrawWindow(Handle, IntPtr.Zero, IntPtr.Zero,
                RDW_FRAME | RDW_IUPDATENOW | RDW_INVALIDATE);
        }
    }
    protected override void WndProc(ref Message m) {
        base.WndProc(ref m);
        if (m.Msg == WM_NCPAINT && BorderColor != Color.Transparent &&
            BorderStyle == System.Windows.Forms.BorderStyle.Fixed3D) {
            var hdc = GetWindowDC(this.Handle);
            using (var g = Graphics.FromHdcInternal(hdc))
            using (var p = new Pen(BorderColor))
                g.DrawRectangle(p, new Rectangle(0, 0, Width - 1, Height - 1));
            ReleaseDC(this.Handle, hdc);
        }
    }
    protected override void OnSizeChanged(EventArgs e) {
        base.OnSizeChanged(e);
        RedrawWindow(Handle, IntPtr.Zero, IntPtr.Zero,
               RDW_FRAME | RDW_IUPDATENOW | RDW_INVALIDATE);
    }
}

Result

Here is the result using different colors and different states. All states of border-style is supported as you can see in below image and you can use any color for border:

enter image description here

Download

You can clone or download the working example:

More Related Contents:

  1. How do I make a textbox that only accepts numbers?
  2. Redirect console output to textbox in separate program
  3. Loop through Textboxes
  4. How to remove the focus from a TextBox in WinForms?
  5. Trying to use the C# SpellCheck class
  6. Change the borderColor of the TextBox
  7. How to remove all event handlers from an event
  8. Get current folder path
  9. How to detect Windows shutdown or logoff
  10. List vs BindingList Advantages/DisAdvantages
  11. How do I fix a .NET windows application crashing at startup with Exception code: 0xE0434352?
  12. Create dynamic buttons in a grid layout – Create a magic square UI
  13. How to clear the text of all textBoxes in the form?
  14. Windows Forms Graphic Issue on Windows 10 OS
  15. how to delay shutdown and run a process in window service
  16. Hide form instead of closing when close button clicked
  17. Is it possible to Embed Gecko or Webkit in a Windows Form just like a WebView?
  18. How can I make a ComboBox non-editable in .NET?
  19. How can we change the background color of all other forms from one form?
  20. Data binding for TextBox
  21. How to register Windows Forms with Simple Injector
  22. Hide some properties in PropertyGrid at run-time
  23. Create custom shape for button
  24. Winforms TableLayoutPanel adding rows programmatically
  25. Auto-width of ComboBox’s content
  26. How can I show a tooltip on a disabled button?
  27. How to get the screenshot of the form
  28. How to catch a key press on a C# .NET form
  29. ComboBox AutoComplete on SubString
  30. How to get DPI in C# .NET?

Leave a Comment