WPF ListView 选中问题

WPF ListView 选中问题

 摘自：http://www.cnblogs.com/BBHor/archive/2013/04/28/VisualTreeHelper-PreviewMouseDown.html

在项目中遇到了这样的问题，ListView通过数据绑定，有模板的情况下ListViewItem 里面的子控件点击之后默认是子控件获得焦点而不是Item获的焦点。

往往需要获取一个ListViewItem  而不是他的子控件，这时候应该怎么办呢？

先看前台XAML：

 1  <ListView x:Name="lv_VMlist"
 2                           PreviewMouseDown="lv_VMlist_PreviewMouseDown"
 3                           SelectionChanged="lv_VMlist_SelectionChanged">
 4                     <ListView.View>
 5                         <GridView>
 6                             <GridView.Columns>
 7                                 <GridViewColumn Width="100"
 8                                                 DisplayMemberBinding="{Binding CallerID}"
 9                                                 Header="主叫方号码" />
10                                 <GridViewColumn Width="110"
11                                                 DisplayMemberBinding="{Binding Duration}"
12                                                 Header="语音邮件长度" />
13                                 <GridViewColumn Width="70"
14                                                 DisplayMemberBinding="{Binding External}"
15                                                 Header="是否是外线" />
16                                 <GridViewColumn Width="80"
17                                                 DisplayMemberBinding="{Binding Type,
18                                                                                Converter={StaticResource etsc}}"
19                                                 Header="类型" />
20                                 <GridViewColumn Width="70"
21                                                 DisplayMemberBinding="{Binding AttachCount}"
22                                                 Header="附件个数" />
23                                 <GridViewColumn Width="120"
24                                                 DisplayMemberBinding="{Binding Time}"
25                                                 Header="时间" />
26                                 <GridViewColumn Width="180" Header="操作">
27                                     <GridViewColumn.CellTemplate>
28                                         <HierarchicalDataTemplate>
29                                             <StackPanel Name="stackPanel" Orientation="Horizontal">
30                                                 <Button Name="btnPlay"
31                                                         Margin="0,0,5,0"
32                                                         Command="{Binding RelativeSource={RelativeSource FindAncestor,
33                                                                                                          AncestorLevel=1,
34                                                                                                          AncestorType={x:Type ListView}},
35                                                                           Path=DataContext.OnPlay}"
36                                                         Content="播放"
37                                                         Focusable="False" />
38                                                 <Button Name="btnStop"
39                                                         Margin="0,0,5,0"
40                                                         Command="{Binding RelativeSource={RelativeSource FindAncestor,
41                                                                                                          AncestorLevel=1,
42                                                                                                          AncestorType={x:Type ListView}},
43                                                                           Path=DataContext.OnStop}"
44                                                         Content="停止" />
45                                                 <Button Name="btnSaveAs"
46                                                         Margin="0,0,5,0"
47                                                         Click="btnSaveClick"
48                                                         Content="另存为"
49                                                         ToolTip="将语音邮件保存到本地" />
50                                                 <Button Name="btnDel"
51                                                         Margin="0,0,5,0"
52                                                         Command="{Binding RelativeSource={RelativeSource FindAncestor,
53                                                                                                          AncestorLevel=1,
54                                                                                                          AncestorType={x:Type ListView}},
55                                                                           Path=DataContext.OnDelete}"
56                                                         Content="删除"
57                                                         ToolTip="删除本条语音邮件" />
58                                                 <Button Name="btnSendTo"
59                                                         Margin="0,0,5,0"
60                                                         Content="转发"
61                                                         ToolTip="将本条语音邮件转发给他人" />
62                                             </StackPanel>
63                                         </HierarchicalDataTemplate>
64                                     </GridViewColumn.CellTemplate>
65                                 </GridViewColumn>
66                             </GridView.Columns>
67                         </GridView>
68                     </ListView.View>
69                 </ListView>

要下手去寻找这时候得借助WPF里面的一个神奇的类：VisualTreeHelper  有了这个类几乎能得到界面的任何东西。当然了，先行条件是在子控件的事件触发之前就要出发一个事件去获取ListViewItem，此时我们想到一个事件就是PreviewMouseDown，因为他是鼠标事件，所以优先级比较高，当他触发了之后才会触发子控件的一些Click事件等

 1   private void lv_VMlist_PreviewMouseDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
 2         {
 3             int index = -1;
 4             DependencyObject depObj = e.OriginalSource as DependencyObject;
 5
 6             if (depObj == null) return;
 7
 8             do
 9             {
10                 depObj = VisualTreeHelper.GetParent(depObj);
11
12                 //有可能是点击到listviewitem之外的东西，例如滚动条，这时候会为null
13                 if (depObj == null) break;
14
15                 //得到listviewitem
16                 if (depObj.GetType() == typeof(ListViewItem))
17                 {
18                     //再去获取父级，用来得到索引
19                     DependencyObject parent = VisualTreeHelper.GetParent(depObj);
20
21                     for (int i = 0; i < VisualTreeHelper.GetChildrenCount(parent); i++)
22                     {
23                         if (depObj == VisualTreeHelper.GetChild(parent, i))
24                         {
25                             //得到索引后马上跳出
26                             index = i;
27                             break;
28                         }
29                     }
30                     break;
31                 }
32             }
33             while (depObj != null);
34
35             //证明已经找到
36             if (index > -1)
37             {
38                 lv_VMlist.SelectedIndex = index;
39             }
40         }

但是需要注意的是，这样写思路倒是简单，就是数据量大的清空可能会影响效率，慎用！