简单的水印输入框

using System;

using System.Collections.Generic;

using System.Text;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Data;

using System.Windows.Documents;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Imaging;

using System.Windows.Shapes;



namespace WisHotel

{

    public class WaterMarkBox : TextBox

    {

        #region MaskText

        /// <summary>

        /// view sort style, desc arrow

        /// </summary>

        public static readonly DependencyProperty MaskTextProperty = DependencyProperty.Register("MaskText", typeof(string), typeof(WaterMarkBox));



        public string MaskText

        {

            get { return (string)GetValue(MaskTextProperty); }

            set { SetValue(MaskTextProperty, value); }

        }

        #endregion



        public WaterMarkBox()

        {

            Loaded += (sender, args) =>

                {

                    if (string.IsNullOrEmpty(base.Text))

                    {

                        base.Text = MaskText;

                        base.Foreground = Brushes.Gray;

                    }

                };



            base.GotFocus += (sender, args) =>

            {

                base.Foreground = Brushes.Black;

                if (base.Text == MaskText)

                    base.Text = string.Empty;

            };

            base.LostFocus += (sender, args) =>

            {

                if (!string.IsNullOrEmpty(base.Text))

                    return;



                base.Text = MaskText;

                base.Foreground = Brushes.Gray;

            };

        }



        public new string Text

        {

            get

            {

                if (base.Text == MaskText)

                    return string.Empty;

                else

                    return base.Text;

            }

            set { base.Text = value; }

        }

    }



}

<btn:WaterMarkBox Width="150" Height="20" MaskText="输入想要查找的房号..."/>