SilverLight学习笔记--利用DependencyProperty依赖属性创建自备录入过滤功能的TextBox控件...

      在这里我们要创建一个具备录入过滤功能的TextBox控件，我们为此控件创建了一个名为FilterProperty的依赖属性和一个名为MyFilter的CLR属性，我们通过设置MyFilter属性来影响此TextBox控件的录入过滤效果，例如：当我们设置MyFilter属性为Alpha时，我们在此TextBox控件中敲击任何数字键将不会有什么反应，因为此时，它只接受英文字母。其余的过滤效果以此类推。
       一、创建我们的这个自定义控件。
      打开VS2008，新建一个Silverlight类库，命名为:SLFilterTextBox，创建如下图
                             
  把Class1.cs改名为MyFilterTextBox.cs，其全部代码如下:
                           

using  System;
using  System.Net;
using  System.Windows;
using  System.Windows.Controls;
using  System.Windows.Documents;
using  System.Windows.Ink;
using  System.Windows.Input;
using  System.Windows.Media;
using  System.Windows.Media.Animation;
using  System.Windows.Shapes;

namespace  SLFilterTextBox
{
    过滤类型枚举值#region 过滤类型枚举值
    public enum TextBoxFilterType
    {
        None,
        PositiveInteger,
        Integer,
        PositiveDecimal,
        Decimal,
        Alpha,
    }
    #endregion

    public class MyFilterTextBox:TextBox
    {

        声明一个依赖属性FilterProperty#region 声明一个依赖属性FilterProperty
        public static readonly DependencyProperty FilterProperty;
        #endregion

        定义一个CLR属性MyFilter来操作依赖属性FilterProperty#region 定义一个CLR属性MyFilter来操作依赖属性FilterProperty
        //因为依赖属性不能像普通CLR属性那样直接赋值，依赖属性不能直接使用，所以我们只能隔山打牛，通过定义一个CLR属性来屏蔽对依赖属性的操作
        //而具体操作的实现是通过定义GetFilter()方法以及SetFilter()方法来达到
        public TextBoxFilterType MyFilter
        {
            get
            {
                return GetFilter(this); //得到当前的FilterProperty依赖属性值
            }
            set
            {
                SetFilter(this, value);  //设置当前的FilterProperty依赖属性值
            }
        }
        #endregion

        定义GetFilter()与SetFilter()方法来间接操作Filter property依赖属性#region 定义GetFilter()与SetFilter()方法来间接操作Filter property依赖属性

        /**//// 取得 Filter property依赖属性值. 
        public static TextBoxFilterType GetFilter(DependencyObject d)
        {
            return (TextBoxFilterType)d.GetValue(FilterProperty);
        }

        /**//// 设置 Filter property 依赖属性值
        public static void SetFilter(DependencyObject d, TextBoxFilterType value)
        {
            d.SetValue(FilterProperty, value);
        }
        #endregion

        静态构造函数(在此构造函数中注册上面声明的依赖属性)#region 静态构造函数(在此构造函数中注册上面声明的依赖属性)
        static MyFilterTextBox()
        {
             //在静态构造函数中注册此依赖属性
             //因为依赖属性需要用DependencyProperty的Register静态方法来创建
              FilterProperty =DependencyProperty.Register("Filter",
                                                    typeof(TextBoxFilterType),//此属性数据类型属于上面定义的过滤类型枚举值
                                                    typeof(MyFilterTextBox), //指定此依赖属性的所有者是MyFilterTextBox控件(一般是当前代码所在的类)
                                                    new PropertyMetadata(OnFilterChanged)); //当依赖属性值改变时会触发此委托OnFilterChanged

              
        }
        #endregion

        OnFilterChanged委托负责给TextBox的keyDown事件定义不同的行为约束#region OnFilterChanged委托负责给TextBox的keyDown事件定义不同的行为约束
        //也即：当给MyFilterTextBox控件的MyFilter属性赋值时，通过OnFilterChanged来判断当前MyFilter属性是何值
        //并根据不同的取值赋予MyFilterTextBox控件不同的KeyDown行为特征
        private static void OnFilterChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            TextBox textBox = d as TextBox;
            if (TextBoxFilterType.None != (TextBoxFilterType)e.OldValue)
            {
                textBox.KeyDown -= new KeyEventHandler(textBox_KeyDown);
            }
            if (TextBoxFilterType.None != (TextBoxFilterType)e.NewValue)
            {
                textBox.KeyDown += new KeyEventHandler(textBox_KeyDown);
            }
        }
        #endregion 

        TextBox控件的KeyDown事件行为定义#region TextBox控件的KeyDown事件行为定义

        textBox_KeyDown 事件委托处理(根据不同的filterType，赋予不同的Handled)#region textBox_KeyDown 事件委托处理(根据不同的filterType，赋予不同的Handled)
        private static void textBox_KeyDown(object sender, KeyEventArgs e)
        {
            // bypass other keys!
            if (IsValidOtherKey(e.Key))
            {
                return;
            }
            //
            TextBoxFilterType filterType = GetFilter((DependencyObject)sender);
            TextBox textBox = sender as TextBox;
            if (null == textBox)
            {
                textBox = e.OriginalSource as TextBox;
            }
            //
            switch (filterType)
            {
                case TextBoxFilterType.PositiveInteger:
                    e.Handled = !IsValidIntegerKey(textBox, e.Key, e.PlatformKeyCode, false);
                    break;
                case TextBoxFilterType.Integer:
                    e.Handled = !IsValidIntegerKey(textBox, e.Key, e.PlatformKeyCode, true);
                    break;
                case TextBoxFilterType.PositiveDecimal:
                    e.Handled = !IsValidDecmialKey(textBox, e.Key, e.PlatformKeyCode, false);
                    break;
                case TextBoxFilterType.Decimal:
                    e.Handled = !IsValidDecmialKey(textBox, e.Key, e.PlatformKeyCode, true);
                    break;
                case TextBoxFilterType.Alpha:
                    e.Handled = !IsValidAlphaKey(e.Key);
                    break;
            }
        }
        #endregion

        允许除数字与字母外的其它允许的按键#region 允许除数字与字母外的其它允许的按键
        private static bool IsValidOtherKey(Key key)
        {
            // allow control keys
            if ((Keyboard.Modifiers & ModifierKeys.Control) != 0)
            {
                return true;
            }
            // allow
            // Back, Tab, Enter, Shift, Ctrl, Alt, CapsLock, Escape, PageUp, PageDown
            // End, Home, Left, Up, Right, Down, Insert, Delete 
            // except for space!
            // allow all Fx keys
            if (
                (key < Key.D0 && key != Key.Space)
                || (key > Key.Z && key < Key.NumPad0))
            {
                return true;
            }
            // we need to examine all others!
            return false;
        }
        #endregion

        允许整数数字键#region 允许整数数字键
        private static bool IsValidIntegerKey(TextBox textBox, Key key, int platformKeyCode, bool negativeAllowed)
        {
            if ((Keyboard.Modifiers & ModifierKeys.Shift) != 0)
            {
                return false;
            }
            if (Key.D0 <= key && key <= Key.D9)
            {
                return true;
            }
            if (Key.NumPad0 <= key && key <= Key.NumPad9)
            {
                return true;
            }
            if (negativeAllowed && (key == Key.Subtract || (key == Key.Unknown && platformKeyCode == 189)))
            {
                return 0 == textBox.Text.Length;
            }
            //
            return false;
        }
        #endregion

        允许小数数字键#region 允许小数数字键
        private static bool IsValidDecmialKey(TextBox textBox, Key key, int platformKeyCode, bool negativeAllowed)
        {
            if (IsValidIntegerKey(textBox, key, platformKeyCode, negativeAllowed))
            {
                return true;
            }
            if (key == Key.Decimal || (key == Key.Unknown && platformKeyCode == 190))
            {
                return !textBox.Text.Contains(".");
            }
            return false;
            //
        }
        #endregion

        允许字母键#region 允许字母键
        private static bool IsValidAlphaKey(Key key)
        {
            if (Key.A <= key && key <= Key.Z)
            {
                return true;
            }
            //
            return false;
            //
        }
        #endregion
        #endregion
    }
}

 这样，我们就创建了我们的自定义TextBox控件，现在我们来应用它。

  二、应用我们创建的TextBox控件
   现在我们新建一个Silverlight应用程序，命名为MySLTextBoxTest，创建后如下图:
                        
在项目MySLTextBoxTest中添加引用--浏览--引入我们前面生成的自定义控件(SLFilterTextBox.dll)。
                        
引入后程序如下图:

                        

  接下来先编辑我们的界面，Page.xaml代码如下:
 

< UserControl x:Class = " MySLTextBoxTest.Page "
    xmlns = " http://schemas.microsoft.com/winfx/2006/xaml/presentation "  
    xmlns:x = " http://schemas.microsoft.com/winfx/2006/xaml "  
    xmlns:mysrc = " clr-namespace:SLFilterTextBox;assembly=SLFilterTextBox "
    Width = " 450 "  Height = " 300 " >
   < Canvas Width = " 450 "  Height = " 300 "  Background = " Wheat "  HorizontalAlignment = " Center " >
       < TextBlock Margin = " 10,20,20,20 "  Text = " 自定义TextBox示例 "  Foreground = " Green "   FontSize = " 18 "  Width = " 200 "  HorizontalAlignment = " Center "   ></ TextBlock >
     < Grid Width = " 400 "  Height = " 300 "  Margin = " 10,60,20,20 "   >
         < Grid.RowDefinitions >
             < RowDefinition Height = " Auto " />
             < RowDefinition Height = " Auto " />
             < RowDefinition Height = " Auto " />
             < RowDefinition Height = " Auto " />
             < RowDefinition Height = " Auto " />
             < RowDefinition Height = " Auto " />
             < RowDefinition Height = " Auto " />
         </ Grid.RowDefinitions >
         < Grid.ColumnDefinitions >
             < ColumnDefinition Width = " * "   />
             < ColumnDefinition Width = " * " />
         </ Grid.ColumnDefinitions >
    
         < TextBlock Grid.Column = " 0 "  Text = " 请输入正整数 "   />
         < mysrc:MyFilterTextBox x:Name = " txtBxPositiveInteger "  Grid.Column = " 1 " ></ mysrc:MyFilterTextBox >
    
         < TextBlock Grid.Column = " 0 "  Grid.Row = " 2 "  Text = " 请输入整数 " />
         < mysrc:MyFilterTextBox x:Name = " txtBxOnlyInteger "  Grid.Row = " 2 "   Grid.Column = " 1 " ></ mysrc:MyFilterTextBox >
    
         < TextBlock Grid.Column = " 0 "  Grid.Row = " 3 "  Text = " 请输入正小数 " />
         < mysrc:MyFilterTextBox x:Name = " txtBxOnlyPositiveDecimal "  Grid.Column = " 1 "  Grid.Row = " 3 "   ></ mysrc:MyFilterTextBox >
    
         < TextBlock Grid.Column = " 0 "  Grid.Row = " 4 "  Text = " 请输入小数 " />
         < mysrc:MyFilterTextBox x:Name = " txtBxOnlyDecimal "  Grid.Column = " 1 "  Grid.Row = " 4 "   ></ mysrc:MyFilterTextBox >

         < TextBlock Grid.Column = " 0 "  Grid.Row = " 5 "  Text = " 请输入字母 " />
         < mysrc:MyFilterTextBox x:Name = " txtBxOnlyAlphabets "  Grid.Column = " 1 "  Grid.Row = " 5 "
                              >   </ mysrc:MyFilterTextBox >
     </ Grid >
     </ Canvas >
</ UserControl >

 在此代码中，我们要引入我们的自定义控件的程序集:

 xmlns:mysrc = " clr-namespace:SLFilterTextBox;assembly=SLFilterTextBox "

然后，我们在后台代码中设置自定义TextBox控件的MyFilter属性，Page.xaml.cs全部代码如下:

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Net;
using  System.Windows;
using  System.Windows.Controls;
using  System.Windows.Documents;
using  System.Windows.Input;
using  System.Windows.Media;
using  System.Windows.Media.Animation;
using  System.Windows.Shapes;
using  SLFilterTextBox;  // 引入我们自定义控件空间

namespace  MySLTextBoxTest
{
     public   partial   class  Page : UserControl
    {
         public  Page()
        {
            InitializeComponent();

            Loaded += new  RoutedEventHandler(Page_Loaded);
        }

         private   void  Page_Loaded( object  sender, RoutedEventArgs e)
        {
             this .txtBxOnlyAlphabets.MyFilter  =  SLFilterTextBox.TextBoxFilterType.Alpha;
             this .txtBxOnlyDecimal.MyFilter  =  SLFilterTextBox.TextBoxFilterType.Decimal;
             this .txtBxOnlyInteger.MyFilter  =  SLFilterTextBox.TextBoxFilterType.Integer;
             this .txtBxOnlyPositiveDecimal.MyFilter  =  SLFilterTextBox.TextBoxFilterType.PositiveDecimal;
             this .txtBxPositiveInteger.MyFilter  =  SLFilterTextBox.TextBoxFilterType.PositiveInteger;
        }
    }
}

生成项目后F5运行，效果如图:
                        
我们可以不按要求在TextBox中录入数据，可以看到相关录入过滤效果。


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转载于:https://www.cnblogs.com/wsdj-ITtech/archive/2009/09/11/1564463.html