直接上源码
public class WaterTextBox : TextBox
{
//private const int EM_SETCUEBANNER = 0x1501;
//[DllImport("user32.dll", CharSet = CharSet.Auto)]
//private static extern Int32 SendMessage
// (IntPtr hWnd, int msg, int wParam, [MarshalAs(UnmanagedType.LPWStr)] string lParam);
string waterText = string.Empty;
[Category("外观")]
[Description("设置水印文本")]
[DefaultValue(typeof(String), "提示文字")]
public string WaterText
{
get { return waterText; }
set
{
waterText = value;
this.Invalidate();
}
}
public WaterTextBox()
{
// base.SetStyle(
//ControlStyles.UserPaint | // 控件将自行绘制，而不是通过操作系统来绘制
//ControlStyles.OptimizedDoubleBuffer | // 该控件首先在缓冲区中绘制，而不是直接绘制到屏幕上，这样可以减少闪烁
//ControlStyles.AllPaintingInWmPaint | // 控件将忽略 WM_ERASEBKGND 窗口消息以减少闪烁
//ControlStyles.ResizeRedraw | // 在调整控件大小时重绘控件
//ControlStyles.SupportsTransparentBackColor, // 控件接受 alpha 组件小于 255 的 BackColor 以模拟透明
//true); // 设置以上值为 true
// base.UpdateStyles();
base.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
this.BorderStyle = BorderStyle.FixedSingle;
//this.BorderStyle = Forms.BorderStyle.None;
this.SuspendLayout();
this.Font = new System.Drawing.Font("微软雅黑", 9f);
this.ResumeLayout(false);
this.WaterText = "水印文字";
this.AutoSize = false;
this.Height = ;
HelpText = "选择";
HelpWidth = ; }
[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
static extern IntPtr LoadLibrary(string lpFileName); /// <summary>
/// 支持透明背景
/// </summary>
protected override CreateParams CreateParams
{
get
{
if (BackColor != Color.Transparent) return base.CreateParams;
CreateParams prams = base.CreateParams;
if (LoadLibrary("msftedit.dll") != IntPtr.Zero)
{
prams.ExStyle |= 0x020;
prams.ClassName = "RICHEDIT50W";
}
return prams;
}
} public int HelpWidth { get; set; }
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
DrawBorder(ref m);
if (m.Msg == 0xF)
{
WmPaint(ref m);
} }
Point mPoint = Point.Empty;
protected override void OnMouseMove(MouseEventArgs e)
{
mPoint = e.Location;
base.OnMouseMove(e);
} // public override Cursor Cursor
//{
// get
// {
// var rect = ClientRectangle;
// rect.X = ClientRectangle.Width - HelpWidth;
// rect.Width = HelpWidth;
// if (rect.Contains(mPoint))
// return Cursors.Hand;
// return base.Cursor; // }
// set
// {
// base.Cursor = value;
// }
//}
public Color BorderColor
{
get { return borderColor; }
set { borderColor = value; }
}
private Color borderColor = Color.Orange; // default border color is black
private static int WM_NCPAINT = 0x0085; // WM_NCPAINT message
private static int WM_ERASEBKGND = 0x0014; // WM_ERASEBKGND message
private static int WM_PAINT = 0x000F; // WM_PAINT message
public event Action<Point> OnDrawText;
public bool IsSelect { get; set; }
public string HelpText { get; set; }
StringFormat sf = new StringFormat() { LineAlignment = StringAlignment.Center, Alignment = StringAlignment.Center };
[DllImport("user32.dll")]
static extern int SetWindowRgn(IntPtr hWnd, IntPtr hRgn, bool bRedraw); [DllImport("gdi32.dll")]
static extern IntPtr CreateRoundRectRgn(int x1, int y1, int x2, int y2, int cx, int cy);
public void DrawBorder(ref Message message)
{
if (message.Msg == WM_NCPAINT || message.Msg == WM_ERASEBKGND ||
message.Msg == WM_PAINT)
{ using (Graphics graphics = Graphics.FromHwnd(this.Handle))
{
if (this.BorderStyle == BorderStyle.FixedSingle)
{
Rectangle rectangle = this.ClientRectangle;
ControlPaint.DrawBorder(graphics, rectangle,
borderColor, ButtonBorderStyle.Solid);
graphics.Dispose();
message.Result = (IntPtr);
} //SetWindowRgn(this.Handle, CreateRoundRectRgn(0, 0, this.Width + 1, Height + 1, 5, 5), true); } }
}
protected override void OnPaintBackground(PaintEventArgs e)
{ base.OnPaintBackground(e);
e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
using (GraphicsPath path = new GraphicsPath())
{
path.AddArc(, , Height - , Height - , , );
path.AddArc(Width - Height, , Height - , Height - , , );
path.CloseFigure(); e.Graphics.FillPath(Brushes.Orange, path);
using (Pen pen = new Pen(Color.Green))
{
e.Graphics.DrawPath(pen, path);
}
}
} private void WmPaint(ref Message m)
{
using (Graphics graphics = Graphics.FromHwnd(base.Handle))
{
if (string.IsNullOrEmpty(Text))
{
TextFormatFlags format =
TextFormatFlags.EndEllipsis |
TextFormatFlags.VerticalCenter;
if (Multiline)
{
format =
TextFormatFlags.EndEllipsis |
TextFormatFlags.VerticalCenter | TextFormatFlags.Left;
}
if (RightToLeft == RightToLeft.Yes)
{
format |= TextFormatFlags.RightToLeft | TextFormatFlags.Right;
}
TextRenderer.DrawText(
graphics,
WaterText,
Font,
ClientRectangle,
Color.Gray,
format);
}
//if (IsSelect)
//{
// var rect = ClientRectangle;
// rect.X = ClientRectangle.Width - HelpWidth;
// rect.Width = HelpWidth;
// graphics.FillRectangle(Brushes.Goldenrod, rect);
// using (var brush = new SolidBrush(Color.White))
// graphics.DrawString(HelpText, Font, brush, rect, sf);
// if(OnDrawText!=null)
// {
// OnDrawText(rect.Location);
// }
//} } } }
把这个放到项目中，然后重新生成项目，最后直接在工具箱上拖拽WaterTextBox就可以用