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最近发现一个有趣的事，通过Window.dataContent来设置绑定以后，
窗体关闭以后 ViewModel 并没有释放，再次调用改窗体后，前一个ViewModel才释放，
或者是程序关闭以后才释放 ，搞不懂。。。
如果要马上释放ViewModel可以在Window关闭以后将DataContent 设置为null ，
这样ViewModel是可以释放的
下面是测试代码，大神请指教！
主窗体：
<Window x:Class="WeakViewModel.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WeakViewModel"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Grid>
<Button Content="Win1" HorizontalAlignment="Left" Margin="367,211,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"/>
<Button Content="GC" HorizontalAlignment="Left" Margin="128,211,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click_1"/>
</Grid>
</Window>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void Button_Click(object sender, RoutedEventArgs e)
{
TestWindow win = new TestWindow();
win.Owner = this;
win.DataContext = ViewModel.Default;
win.Show();
}
private void Button_Click_1(object sender, RoutedEventArgs e)
{
GC.Collect();
}
}
测试窗体：
<Window x:Class="WeakViewModel.TestWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:WeakViewModel"
mc:Ignorable="d"
Title="TestWindow" Height="300" Width="300">
<Grid>
<TextBox HorizontalAlignment="Left" Height="23" Margin="96,111,0,0" TextWrapping="Wrap" Text="{Binding Path=Text}" VerticalAlignment="Top" Width="120"/>
</Grid>
</Window>
public partial class TestWindow : Window
{
public TestWindow()
{
InitializeComponent();
Closed += TestWindow_Closed;
}
~ TestWindow()
{
MessageBox.Show("释放TestWindow");
}
private void TestWindow_Closed(object sender, EventArgs e)
{
//注释这个行就能看出差别
DataContext = null;
}
}
测试ViewModel：
public class ViewModel
{
private static WeakReference _default = null;
private static object locker = new object();
public static ViewModel Default
{
get
{
if(_default==null||!_default.IsAlive)
{
lock (locker)
{
_default = new WeakReference(new ViewModel());
}
}
return _default.Target as ViewModel;
}
}
private ViewModel()
{
}
~ViewModel()
{
MessageBox.Show("释放 ViewModel"+Text);
}
private string _text = string.Empty;
public string Text
{
get
{
return _text;
}
set
{
_text = value;
}
}
}
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