silverlight3取消了watertextbox控件，只有自己实现了个，实现了和textbox一样的无差异使用，只需要设置defaulttext就可以了
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media; namespace iLIS.Common.Controls
{
/// <summary>
/// 自定义WatermarkedTextBox控件
/// </summary>
public class WatermarkedTextBox : TextBox
{
/// <summary>
/// 水印文字
/// </summary>
public string DefaultText
{
get
{
return (string)GetValue(DefaultTextProperty);
}
set
{
SetValue(DefaultTextProperty, value);
}
}
/// <summary>
/// 文本框中的文字
/// 文字为水印文字时返回空
/// </summary>
public string Text
{
get
{
if (base.Text == DefaultText)
{
return string.Empty;
}
else
{
return base.Text;
}
}
set
{
base.Text = value;
}
}
/// <summary>
/// 获取或设置一个用于描述前景色的画笔。
/// 用于绘制控件的前景的画笔。默认值为 System.Windows.Media.Colors.Black。
/// </summary>
public new Brush Foreground
{
get
{
return (Brush)GetValue(ForegroundProperty);
}
set
{
SetValue(ForegroundProperty, value);
}
} // Using a DependencyProperty as the backing store for Foreground. This enables animation, styling, binding, etc...
public static new readonly DependencyProperty ForegroundProperty =
DependencyProperty.Register("Foreground", typeof(Brush), typeof(WatermarkedTextBox), new PropertyMetadata((o, e) =>
{
SolidColorBrush brush = e.NewValue as SolidColorBrush;
if (brush != null && brush.Color != Colors.Gray)
{
(o as WatermarkedTextBox).oldBrush = brush;
}
})); private Brush oldBrush = new SolidColorBrush(Colors.Black);
/// <summary>
/// 默认文本
/// </summary>
public static readonly DependencyProperty DefaultTextProperty =
DependencyProperty.Register("DefaultText", typeof(string), typeof(WatermarkedTextBox), new PropertyMetadata(""));
public event TextChangedEventHandler WatermarkedTextChanged;
/// <summary>
/// 初始化 System.Windows.Controls.TextBox 类的新实例。
/// </summary>
public WatermarkedTextBox()
{
base.TextChanged += new TextChangedEventHandler(OnWatermarkedTextBox_TextChanged);
} /// <summary>
///在派生类中重写后，每当应用程序代码或内部进程（如重新生成布局处理过程）调用 System.Windows.Controls.Control.ApplyTemplate()，都将调用此方法。
///简而言之，这意味着就在UI 元素在应用程序中显示前调用该方法。有关更多信息，请参见“备注”。
/// </summary>
public override void OnApplyTemplate()
{
this.Text = this.DefaultText;
base.OnApplyTemplate();
base.Foreground = new SolidColorBrush(Colors.Gray);
}
/// <summary>
///在 System.Windows.UIElement.GotFocus 事件发生之前调用。
/// </summary>
/// <param name="e">事件的数据</param>
protected override void OnGotFocus(RoutedEventArgs e)
{
if (string.Equals(base.Text, this.DefaultText, StringComparison.OrdinalIgnoreCase))
{
base.Text = string.Empty;
}
base.OnGotFocus(e);
}
/// <summary>
///在 System.Windows.UIElement.LostFocus 事件发生之前调用。
/// </summary>
/// <param name="e">事件的数据</param>
protected override void OnLostFocus(RoutedEventArgs e)
{
if (string.IsNullOrEmpty(base.Text))
{
base.Text = this.DefaultText;
base.Foreground = new SolidColorBrush(Colors.Gray);
}
base.OnLostFocus(e);
}
/// <summary>
/// 文本改变时调用
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void OnWatermarkedTextBox_TextChanged(object sender, TextChangedEventArgs e)
{
if (!string.Equals(base.Text, this.DefaultText, StringComparison.OrdinalIgnoreCase))
{
base.Foreground = oldBrush;
if (this.WatermarkedTextChanged != null)
{
this.WatermarkedTextChanged(this, e);
}
}
} }
}