winform设置textbox设置水印
1、新建自定义控件
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
using System; using System.Runtime.InteropServices; using System.Windows.Forms; namespace takelinks { public partial class WatermarkTextBox : TextBox//修改为继承自TextBox { public WatermarkTextBox() { InitializeComponent(); } private const uint ECM_FIRST = 0x1500; private const uint EM_SETCUEBANNER = ECM_FIRST + 1; [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)] static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, uint wParam, [MarshalAs(UnmanagedType.LPWStr)] string lParam); private string watermarkText; public string WatermarkText { get { return watermarkText; } set { watermarkText = value; SetWatermark(watermarkText); } } private void SetWatermark(string watermarkText) { SendMessage(this.Handle, EM_SETCUEBANNER, 0, watermarkText); } } }
2、新建的控件除了textbox的功能外还增添了水印的功能
运用
textBox1.WatermarkText = "请输入链接,可以拖拽!";
完!