Change Border Color In TextBox C#

Answer :

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:

Download

You can clone or download the working example:

• Download Zip
• Github repository

You have to draw text manually as well.

protected override void OnPaint(PaintEventArgs e) {     base.OnPaint(e);     Pen penBorder = new Pen(Color.Gray, 1);     Rectangle rectBorder = new Rectangle(e.ClipRectangle.X, e.ClipRectangle.Y, e.ClipRectangle.Width - 1, e.ClipRectangle.Height - 1);     e.Graphics.DrawRectangle(penBorder, rectBorder);      Rectangle textRec = new Rectangle(e.ClipRectangle.X + 1, e.ClipRectangle.Y + 1, e.ClipRectangle.Width - 1, e.ClipRectangle.Height - 1);     TextRenderer.DrawText(e.Graphics, Text, this.Font, textRec, this.ForeColor, this.BackColor, TextFormatFlags.Default); } 

Alternatively you can try to use e.Graphics.DrawString() method if TextRenderer is not giving you desired results (I always have better results with this approach thou).