diff --git a/TextBoxTip.cs b/TextBoxTip.cs
new file mode 100644
index 0000000..0698175
--- /dev/null
+++ b/TextBoxTip.cs
@@ -0,0 +1,122 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Runtime.InteropServices;
+using System.Windows.Forms;
+
+namespace CommonCalss
+{
+    public static class TextBoxTip
+    {
+        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);
+
+        /// <summary>
+        /// 为TextBox设置提示文字
+        /// </summary>
+        /// <param name="textBox">TextBox</param>
+        /// <param name="watermark">提示文字内容</param>
+        public static void SetWatermark(this TextBox textBox, string watermark)
+        {
+            SendMessage(textBox.Handle, EM_SETCUEBANNER, 0, watermark);
+        }
+
+        /// <summary>
+        /// 为ComboBox设置提示文字
+        /// </summary>
+        /// <param name="textBox">ComboBox</param>
+        /// <param name="watermark">提示文字内容</param>
+        public static void SetWatermark(this ComboBox textBox, string watermark)
+        {
+            COMBOBOXINFO info = GetComboBoxInfo(textBox);
+            SendMessage(info.hwndItem, EM_SETCUEBANNER, 0, watermark);
+            //SendMessage(textBox.Handle, EM_SETCUEBANNER, 0, watermark);
+        }
+
+        /// <summary>
+        /// 清除提示文字
+        /// </summary>
+        /// <param name="textBox">ComboBox</param>
+        public static void ClearWatermark(this ComboBox textBox)
+        {
+            SendMessage(textBox.Handle, EM_SETCUEBANNER, 0, string.Empty);
+        }
+
+        [DllImport("user32.dll")]
+        private static extern bool SendMessage(IntPtr hwnd, int msg, int wParam, StringBuilder lParam);
+
+        [DllImport("user32.dll")]
+        private static extern bool GetComboBoxInfo(IntPtr hwnd, ref COMBOBOXINFO pcbi);
+
+        [StructLayout(LayoutKind.Sequential)]
+        private struct COMBOBOXINFO
+        {
+            public int cbSize;
+            public RECT rcItem;
+            public RECT rcButton;
+            public IntPtr stateButton;
+            public IntPtr hwndCombo;
+            public IntPtr hwndItem;
+            public IntPtr hwndList;
+        }
+
+        [StructLayout(LayoutKind.Sequential)]
+        private struct RECT
+        {
+            public int left;
+            public int top;
+            public int right;
+            public int bottom;
+        }
+
+        //private const int EM_SETCUEBANNER = 0x1501;
+        private const int EM_GETCUEBANNER = 0x1502;
+
+        public static void SetCueText(Control control, string text)
+        {
+            if (control is ComboBox)
+            {
+                COMBOBOXINFO info = GetComboBoxInfo(control);
+                SendMessage(info.hwndItem, EM_SETCUEBANNER, 0, text);
+            }
+            else
+            {
+                SendMessage(control.Handle, EM_SETCUEBANNER, 0, text);
+            }
+        }
+
+        private static COMBOBOXINFO GetComboBoxInfo(Control control)
+        {
+            COMBOBOXINFO info = new COMBOBOXINFO();
+            //a combobox is made up of three controls, a button, a list and textbox;
+            //we want the textbox
+            info.cbSize = Marshal.SizeOf(info);
+            GetComboBoxInfo(control.Handle, ref info);
+            return info;
+        }
+
+        public static string GetCueText(Control control)
+        {
+            StringBuilder builder = new StringBuilder();
+            if (control is ComboBox)
+            {
+                COMBOBOXINFO info = new COMBOBOXINFO();
+                //a combobox is made up of two controls, a list and textbox;
+                //we want the textbox
+                info.cbSize = Marshal.SizeOf(info);
+                GetComboBoxInfo(control.Handle, ref info);
+                SendMessage(info.hwndItem, EM_GETCUEBANNER, 0, builder);
+            }
+            else
+            {
+                SendMessage(control.Handle, EM_GETCUEBANNER, 0, builder);
+            }
+            return builder.ToString();
+        }
+    }
+}