WPF中使用VisualBrush的实例

来源：互联网发布：庄子知乎编辑：程序博客网时间：2024/06/07 07:06

本文实现一个名为“你来我往”的小程序，该程序管理着“张三”和“李四”两位童鞋拥有的现金，一开始，两人均拥有100美元的现金，随着将现金从其中一人转移至另外一人，两人拥有的现金数在不断变化，程序可以跟踪这种变化，并正确显示每人拥有的现金数。每次最多可以转移三张纸币，纸币的金额可以是5美元、10美元或者20美元。

程序运行后的效果如图1所示，我们点击“张三”右边的“5美元”“10美元”“20美元”按钮，再点击“Play”按钮，便完成了现金从“张三”向“李四”流动，流动后，“张三”拥有的现金变为135美元，而“李四”仅剩下65美元，运行后的效果如图2所示。

图1 初始状态图

图2 现金流动后的分布图

在点击“张三”右边的“5美元”“10美元”或者“20美元”按钮时，会将“5美元”“10美元”或者“20美元”按钮复制一份进“张三”与“李四”之间的“待支付区”，而完成这个操作就需要使用到VisualBrush。

图3 现金流进待支付区的示意图

点击“Cancel”按钮可以清空“待支付区”中的按钮。

VisualBrush是WPF画刷类Brush的派生类，Brush类是个抽象类，WPF中派生自Brush类的还有：SolidColorBrush（实心画刷）、LinearGradientBrush（线性渐变画刷）、RadialGradientBrush（径向渐变画刷）、ImageBrush、DrawingBrush等。VisualBrush使用Visual对象来绘制区域，Visual对象包括Button、Page等。本例中使用VisualBrush来绘制Rectangle的Fill，最终达到的效果就是将按钮复制进“待支付区”。这部分操作的代码如下所示。

private void AddChildren(Button btn){     VisualBrush vBrush = new VisualBrush(btn);     Rectangle rect = new Rectangle();     rect.Width = btn.ActualWidth;     rect.Height = btn.ActualHeight;     rect.Fill = vBrush;     rect.Opacity = 0.8;     this.StackPanel_Pay.Children.Add(rect);}

代码中，使用按钮初始化VisualBrush，接着，按照按钮的宽度和高度绘制矩形，并将矩形的Fill属性设置为VisualBrush对象，最后将新绘制的矩形添加进“待支付区”。好了，就到这里了。

下面附上本例的完整代码。

MainWindow.xaml文件代码

<Window x:Class="WpfVisualBrushExp.MainWindow"        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        Title="你来我往" Height="350" Width="525" WindowStyle="ToolWindow">    <Grid>        <Grid.RowDefinitions>            <RowDefinition Height="*"></RowDefinition>            <RowDefinition Height="*"></RowDefinition>            <RowDefinition Height="*"></RowDefinition>            <RowDefinition Height="0.2*"></RowDefinition>            <RowDefinition Height="*"></RowDefinition>            <RowDefinition Height="0.2*"></RowDefinition>            <RowDefinition Height="*"></RowDefinition>            <RowDefinition Height="*"></RowDefinition>            <RowDefinition Height="*"></RowDefinition>        </Grid.RowDefinitions>        <Grid.ColumnDefinitions>            <ColumnDefinition Width="*"></ColumnDefinition>            <ColumnDefinition Width="*"></ColumnDefinition>            <ColumnDefinition Width="*"></ColumnDefinition>            <ColumnDefinition Width="0.05*"></ColumnDefinition>            <ColumnDefinition Width="*"></ColumnDefinition>        </Grid.ColumnDefinitions>        <TextBlock Text="张三拥有" Grid.Row="1" Grid.Column="0" HorizontalAlignment="Right" Margin="0,10,0,10" />        <TextBlock x:Name="TextBlock_ZhangsanAmount" Grid.Row="1" Grid.Column="1" HorizontalAlignment="Center" Margin="0,10,0,10" />        <TextBlock Text="美元" Grid.Row="1" Grid.Column="2" HorizontalAlignment="Left" Margin="0,10,0,10" />        <Button x:Name="Button_ToLisiFive" Content="5美元" Grid.Row="0" Grid.Column="4" Click="Button_ToLisiFive_Click" />        <Button x:Name="Button_ToLisiTen" Content="10美元" Grid.Row="1" Grid.Column="4" Click="Button_ToLisiTen_Click" />        <Button x:Name="Button_ToLisiTwenty" Content="20美元" Grid.Row="2" Grid.Column="4" Click="Button_ToLisiTwenty_Click" />                <TextBlock Grid.Row="3" Grid.Column="0" Grid.ColumnSpan="5" Background="Cyan"/>         <StackPanel x:Name="StackPanel_Pay" Background="White" Grid.Row="4" Grid.Column="0" Grid.ColumnSpan="3" Orientation="Horizontal"/>         <StackPanel Grid.Row="4" Grid.Column="4">            <Button x:Name="Button_Pay" Content="Pay"  Click="Button_Pay_Click" />            <Button x:Name="Button_Cancel" Content="Cancel" Click="Button_Cancel_Click" />        </StackPanel>                              <TextBlock Grid.Row="5" Grid.Column="0" Grid.ColumnSpan="5" Background="Cyan"/>                <TextBlock Text="李四拥有" Grid.Row="7" Grid.Column="0" HorizontalAlignment="Right" Margin="0,10,0,10" />        <TextBlock x:Name="TextBlock_LisiAmount" Grid.Row="7" Grid.Column="1" HorizontalAlignment="Center" Margin="0,10,0,10" />        <TextBlock Text="美元" Grid.Row="7" Grid.Column="2" HorizontalAlignment="Left" Margin="0,10,0,10" />        <Button x:Name="Button_ToZhangsanFive" Content="5美元" Grid.Row="6" Grid.Column="4" Click="Button_ToZhangsanFive_Click" />        <Button x:Name="Button_ToZhangsanTen" Content="10美元" Grid.Row="7" Grid.Column="4" Click="Button_ToZhangsanTen_Click" />        <Button x:Name="Button_ToZhangsanTwenty" Content="20美元" Grid.Row="8" Grid.Column="4" Click="Button_ToZhangsanTwenty_Click" />         <TextBlock Grid.Row="0" Grid.Column="3" Grid.RowSpan="9" Background="Cyan"/>    </Grid></Window>

MainWindow.xaml.cs文件代码

//************************************************************  //  // VisualBrush示例代码  //  // Author：三五月儿  //   // Date：2014/08/26 //  // http://blog.csdn.net/yl2isoft  //  //************************************************************  using System;using System.Collections.Generic;using System.Linq;using System.Windows;using System.Windows.Controls;using System.Windows.Media;using System.Windows.Shapes; namespace WpfVisualBrushExp{    /// <summary>    /// MainWindow.xaml 的交互逻辑    /// </summary>    public partial class MainWindow : Window    {        bool isZhangsanPaying = false;        bool isLisiPaying = false;        List<int> zhangsanPayAmountList = new List<int>();        List<int> lisiPayAmountList = new List<int>();         public MainWindow()        {            InitializeComponent();            this.TextBlock_ZhangsanAmount.Text = "100";            this.TextBlock_LisiAmount.Text = "100";        }         #region 张三        private void Button_ToLisiFive_Click(object sender, RoutedEventArgs e)        {            if (ReturnByMaxCount()                || ReturnByLisiIsPaying())            {                return;            }            AddChildren(this.Button_ToLisiFive);            zhangsanPayAmountList.Add(5);            isZhangsanPaying = true;        }         private void Button_ToLisiTen_Click(object sender, RoutedEventArgs e)        {            if (ReturnByMaxCount()                || ReturnByLisiIsPaying())            {                return;            }            AddChildren(this.Button_ToLisiTen);            zhangsanPayAmountList.Add(10);            isZhangsanPaying = true;        }         private void Button_ToLisiTwenty_Click(object sender, RoutedEventArgs e)        {            if (ReturnByMaxCount()                 || ReturnByLisiIsPaying())            {                return;            }            AddChildren(this.Button_ToLisiTwenty);            zhangsanPayAmountList.Add(20);            isZhangsanPaying = true;        }        #endregion //张三         #region 李四        private void Button_ToZhangsanFive_Click(object sender, RoutedEventArgs e)        {            if (ReturnByMaxCount()                || ReturnByZhangsanIsPaying())            {                return;            }            AddChildren(this.Button_ToZhangsanFive);            lisiPayAmountList.Add(5);            isLisiPaying = true;        }         private void Button_ToZhangsanTen_Click(object sender, RoutedEventArgs e)        {            if (ReturnByMaxCount()                || ReturnByZhangsanIsPaying())            {                return;            }            AddChildren(this.Button_ToZhangsanTen);            lisiPayAmountList.Add(10);            isLisiPaying = true;        }         private void Button_ToZhangsanTwenty_Click(object sender, RoutedEventArgs e)        {            if (ReturnByMaxCount()                || ReturnByZhangsanIsPaying())            {                return;            }            AddChildren(this.Button_ToZhangsanTwenty);            lisiPayAmountList.Add(20);            isLisiPaying = true;        }        #endregion //李四         private bool ReturnByMaxCount()        {            if (this.StackPanel_Pay.Children.Count >= 3)            {                MessageBox.Show("一次最多只能支付3张美元。");                return true;            }            return false;        }         private bool ReturnByZhangsanIsPaying()        {            if (isZhangsanPaying == true)            {                MessageBox.Show("张三正在支付中...");                return true;            }            return false;        }         private bool ReturnByLisiIsPaying()        {            if (isLisiPaying == true)            {                MessageBox.Show("李四正在支付中...");                return true;            }            return false;        }         private void AddChildren(Button btn)        {            VisualBrush vBrush = new VisualBrush(btn);            Rectangle rect = new Rectangle();            rect.Width = btn.ActualWidth;            rect.Height = btn.ActualHeight;            rect.Fill = vBrush;            rect.Opacity = 0.8;            this.StackPanel_Pay.Children.Add(rect);        }         private void Button_Pay_Click(object sender, RoutedEventArgs e)        {            if (isZhangsanPaying)            {                int zhangsanAmount = Convert.ToInt32(this.TextBlock_ZhangsanAmount.Text) - zhangsanPayAmountList.Sum(it => it);                int lisiAmount = Convert.ToInt32(this.TextBlock_LisiAmount.Text) + zhangsanPayAmountList.Sum(it => it);                this.TextBlock_ZhangsanAmount.Text = zhangsanAmount.ToString();                this.TextBlock_LisiAmount.Text = lisiAmount.ToString();                zhangsanPayAmountList.Clear();                isZhangsanPaying = false;            }            else            {                int lisiAmount = Convert.ToInt32(this.TextBlock_LisiAmount.Text) - lisiPayAmountList.Sum(it => it);                int zhangsanAmount = Convert.ToInt32(this.TextBlock_ZhangsanAmount.Text) + lisiPayAmountList.Sum(it => it);                this.TextBlock_LisiAmount.Text = lisiAmount.ToString();                this.TextBlock_ZhangsanAmount.Text = zhangsanAmount.ToString();                lisiPayAmountList.Clear();                isLisiPaying = false;            }            this.StackPanel_Pay.Children.Clear();        }         private void Button_Cancel_Click(object sender, RoutedEventArgs e)        {            this.StackPanel_Pay.Children.Clear();            zhangsanPayAmountList.Clear();            lisiPayAmountList.Clear();                      isZhangsanPaying = false;            isLisiPaying = false;        }    }}

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