C# WinForm TextBox添加浮水印效果

標籤：

1、建立項目添加WatermarkTextBox類：

using System;using System.Collections.Generic;using System.Text;using System.Windows.Forms;using System.Drawing;using System.ComponentModel;namespace TextBoxWatermark{    [ToolboxBitmap(typeof(TextBox))]    public class WatermarkTextBox : TextBox    {        private string _emptyTextTip;        private Color _emptyTextTipColor = Color.DarkGray;        private const int WM_PAINT = 0xF;        public WatermarkTextBox()            : base()        {        }        [DefaultValue("")]        public string EmptyTextTip        {            get { return _emptyTextTip; }            set            {                _emptyTextTip = value;                base.Invalidate();            }        }        [DefaultValue(typeof(Color), "DarkGray")]        public Color EmptyTextTipColor        {            get { return _emptyTextTipColor; }            set            {                _emptyTextTipColor = value;                base.Invalidate();            }        }        protected override void WndProc(ref Message m)        {            base.WndProc(ref m);            if (m.Msg == WM_PAINT)            {                WmPaint(ref m);            }        }        private void WmPaint(ref Message m)        {            using (Graphics graphics = Graphics.FromHwnd(base.Handle))            {                if (Text.Length == 0                    && !string.IsNullOrEmpty(_emptyTextTip)                    && !Focused)                {                    TextFormatFlags format =                        TextFormatFlags.EndEllipsis |                        TextFormatFlags.VerticalCenter;                    if (RightToLeft == RightToLeft.Yes)                    {                        format |= TextFormatFlags.RightToLeft | TextFormatFlags.Right;                    }                    TextRenderer.DrawText(                        graphics,                        _emptyTextTip,                        Font,                        base.ClientRectangle,                        _emptyTextTipColor,                        format);                }            }        }    }}

2、在Form中執行個體化控制項並添加：

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms;namespace TextBoxWatermark{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();            TextBoxWatermark.WatermarkTextBox tbName = new WatermarkTextBox();            tbName.EmptyTextTip = "請輸入你的帳號";            tbName.Location = new System.Drawing.Point(116, 63);            tbName.Size = new System.Drawing.Size(150, 21);            tbName.Name = "tbName";            tbName.TabStop = false;            //tbName.TabIndex = 0;            this.Controls.Add(tbName);            TextBoxWatermark.WatermarkTextBox tbPassword = new WatermarkTextBox();            tbPassword.EmptyTextTip = "請輸入你的密碼";            tbPassword.Location = new System.Drawing.Point(116, 90);            tbPassword.Size = new System.Drawing.Size(150, 21);            tbPassword.Name = "tbPassword";            tbPassword.TabStop = false;            //tbName.TabIndex = 0;            this.Controls.Add(tbPassword);        }    }}

 

C# WinForm TextBox添加浮水印效果