WPF中给文本框和密码框添加水印

编辑器加载中...在WPF中，给文本框添加一个水印可以有好几种方法，但是密码框有点不好做了，大部分都是重写控件继承于文本框以及集合依赖属性实现的，

在网上找了很久都没有类似的，在国外网站上看到的，顺便改了一下，当输入内容时水印消失（得到焦点时水印消失，暂时没做），如下如所示：

xaml的页面代码如下（里面的图片可以自己换）：

CS代码如下(可以自己去写简单的控件)：

using System;
using System.Collections.Generic;
using System.Linq;
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.Navigation;
using System.Windows.Shapes;

namespace WpfApplication1
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {

        }

    }

    //密码框的水印附加属性
    public class PasswordBoxMonitor : DependencyObject
    {
        public static bool GetIsMonitoring(DependencyObject obj)
        {
            return (bool)obj.GetValue(IsMonitoringProperty);
        }

        public static void SetIsMonitoring(DependencyObject obj, bool value)
        {
            obj.SetValue(IsMonitoringProperty, value);
        }

        public static readonly DependencyProperty IsMonitoringProperty =
            DependencyProperty.RegisterAttached("IsMonitoring", typeof(bool), typeof(PasswordBoxMonitor), new UIPropertyMetadata(false, OnIsMonitoringChanged));

        public static int GetPasswordLength(DependencyObject obj)
        {
            return (int)obj.GetValue(PasswordLengthProperty);
        }

        public static void SetPasswordLength(DependencyObject obj, int value)
        {
            obj.SetValue(PasswordLengthProperty, value);
        }

        public static readonly DependencyProperty PasswordLengthProperty =
            DependencyProperty.RegisterAttached("PasswordLength", typeof(int), typeof(PasswordBoxMonitor), new UIPropertyMetadata(0));

        private static void OnIsMonitoringChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var pb = d as PasswordBox;
            if (pb == null)
            {
                return;
            }
            if ((bool)e.NewValue)
            {
                pb.PasswordChanged += PasswordChanged;
            }
            else
            {
                pb.PasswordChanged -= PasswordChanged;
            }
        }

        static void PasswordChanged(object sender, RoutedEventArgs e)
        {
            var pb = sender as PasswordBox;
            if (pb == null)
            {
                return;
            }
            SetPasswordLength(pb, pb.Password.Length);
        }
    }

    //文本框的水印附加属性
    public class TextBoxMonitor : DependencyObject
    {
        public static bool GetIsMonitoring(DependencyObject obj)
        {
            return (bool)obj.GetValue(IsMonitoringProperty);
        }

        public static void SetIsMonitoring(DependencyObject obj, bool value)
        {
            obj.SetValue(IsMonitoringProperty, value);
        }

        public static readonly DependencyProperty IsMonitoringProperty =
            DependencyProperty.RegisterAttached("IsMonitoring", typeof(bool), typeof(TextBoxMonitor), new UIPropertyMetadata(false, OnIsMonitoringChanged));

        public static int GetTextBoxLength(DependencyObject obj)
        {
            return (int)obj.GetValue(TextBoxLengthProperty);
        }

        public static void SetTextBoxLength(DependencyObject obj, int value)
        {
            obj.SetValue(TextBoxLengthProperty, value);
        }

        public static readonly DependencyProperty TextBoxLengthProperty =
            DependencyProperty.RegisterAttached("TextBoxLength", typeof(int), typeof(TextBoxMonitor), new UIPropertyMetadata(0));

        private static void OnIsMonitoringChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var tx = d as TextBox;
            if (tx == null)
            {
                return;
            }
            if ((bool)e.NewValue)
            {
                tx.TextChanged += new TextChangedEventHandler(tx_TextChanged);
            }
            else
            {
                tx.TextChanged -= new TextChangedEventHandler(tx_TextChanged);
            }
        }

        static void tx_TextChanged(object sender, TextChangedEventArgs e)
        {
            var tx = sender as TextBox;
            if (tx == null)
            {
                return;
            }
            SetTextBoxLength(tx, tx.Text.Length);
        }


    }

}

posted @ 2012-08-16 16:25 sky300 阅读(1707) 评论(0) 编辑收藏举报

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