这篇文章是我对ChildWindow的理解，举例说明：

有时候在项目中需要弹出子窗体进行一些操作，然后将操作的值返回到父窗体中。

下图是子窗体的界面（比较粗糙。。。。）

下面贴出其代码：

子窗体前台代码

 <controls:ChildWindow x:Class="FineMmarketing.Controls.SelectChild"

            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

            xmlns:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls"

            Width="365" Height="226"

            Title="请选择纬度">

     <Grid x:Name="LayoutRoot" Margin="2" >

         <Grid.RowDefinitions>

             <RowDefinition />

             <RowDefinition Height="Auto" />

         </Grid.RowDefinitions>

         <StackPanel Margin="0,0,0,37">           

             <TextBlock Width="100" Height="30" Text="请输入纬度：" Margin="83 35 0 0" HorizontalAlignment="Left" />

             <TextBox x:Name="Txt" Width="200" Height="30" HorizontalAlignment="Center" Margin="24 0 0 0"/>

         </StackPanel>

        

         <Button x:Name="CancelButton" Content="取消" Click="CancelButton_Click" Width="75" Height="23" HorizontalAlignment="Right" Margin="0,12,0,0" Grid.Row="1" />

         <Button x:Name="OKButton" Content="确定" Click="OKButton_Click" Width="75" Height="23" HorizontalAlignment="Right" Margin="0,12,79,0" Grid.Row="1" />

     </Grid>

 </controls:ChildWindow>

子窗体后台代码

  /// <summary>

         /// 确定按钮

         /// </summary>

         /// <param name="sender"></param>

         /// <param name="e"></param>

         private void OKButton_Click(object sender, RoutedEventArgs e)

         {           

             if (!String.IsNullOrEmpty(this.Txt.Text))

             {

                 Regex reg = new Regex("^[0-9]+$");

                 Match ma = reg.Match(this.Txt.Text.ToString());

                 if (ma.Success)

                 {

                     Num = Convert.ToInt32(this.Txt.Text.ToString());

                     if (Num > 10)

                     {

                         MessageBox.Show("纬度不能超过10！");

                         return;

                     }

                     else

                     {

                         this.Tag = Num;

                     }          

                 }

                 else

                 {

                     MessageBox.Show("请输入正确的纬度！");

                 }

             }

             else

             {

                 MessageBox.Show("请输入纬度！");

             }

             this.DialogResult = true;

         }

  /// <summary>

         /// 取消按钮

         /// </summary>

         /// <param name="sender"></param>

         /// <param name="e"></param>

         private void CancelButton_Click(object sender, RoutedEventArgs e)

         {

             this.DialogResult = false;

         }

然后看一下在父窗体中如何调用子窗体，然后后台定义事件执行子窗体关闭事件。

子窗体后台代码

 SelectChild myChild = new SelectChild();//申明子窗体对象

 定义子窗体关闭事件

 myChild.Closed += new EventHandler(win_Closed);

 

 

  /// <summary>

         /// 子窗口关闭返回值事件

         /// </summary>

         /// <param name="sender"></param>

         /// <param name="e"></param>

         void win_Closed(object sender,EventArgs e)

         {

             bool? result = myChild.DialogResult;

             //判断是否是顶级确定按钮关闭并且有返回值

             if (result.HasValue && result.Value)

             {

                 //是定义在子窗体中的公有的全局变量

                 MessageBox.Show(myChild.txt);

             }

         }