99 lines
2.6 KiB
C#
99 lines
2.6 KiB
C#
using System;
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using System.Collections.Generic;
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using System.ComponentModel;
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using System.Drawing;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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using System.Windows.Forms;
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namespace JYControl
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{
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/// <summary>
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/// TextBox添加水印文字
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/// </summary>
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[ToolboxBitmap(typeof(TextBox))]
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public class WatermarkTextBox : TextBox
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{
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private string _watermark;
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private Color _watermarkColor = Color.DarkGray;
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private const int WM_PAINT = 0xF;
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public WatermarkTextBox()
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: base()
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{
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}
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/// <summary>
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/// 输入需要显示水印文字
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/// </summary>
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///
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[Category("控件属性")]
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[Description("输入需要显示水印文字")]
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[DefaultValue("")]
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public string Watermark
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{
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get { return _watermark; }
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set
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{
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_watermark = value;
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base.Invalidate();
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}
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}
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/// <summary>
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/// 改变水印文字的颜色
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/// </summary>
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///
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[Category("控件属性")]
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[Description("改变水印文字的颜色")]
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[DefaultValue(typeof(Color), "DarkGray")]
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public Color WatermarkColor
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{
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get { return _watermarkColor; }
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set
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{
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_watermarkColor = value;
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base.Invalidate();
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}
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}
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protected override void WndProc(ref Message m)
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{
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base.WndProc(ref m);
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if (m.Msg == WM_PAINT)
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{
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WmPaint(ref m);
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}
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}
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private void WmPaint(ref Message m)
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{
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using (Graphics graphics = Graphics.FromHwnd(base.Handle))
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{
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if (Text.Length == 0
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&& !string.IsNullOrEmpty(_watermark)
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&& !Focused)
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{
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TextFormatFlags format =
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TextFormatFlags.EndEllipsis |
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TextFormatFlags.VerticalCenter;
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if (RightToLeft == RightToLeft.Yes)
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{
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format |= TextFormatFlags.RightToLeft | TextFormatFlags.Right;
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}
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TextRenderer.DrawText(
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graphics,
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_watermark,
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Font,
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base.ClientRectangle,
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_watermarkColor,
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format);
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}
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}
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}
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}
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}
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