[英]Correctly disposing user control and its children
我一直在尋找30分鍾以上,但是我根本無法弄清楚問題出在哪里。 我有一個TabControl
,它的項目將由用戶關閉。 由於每個TabItem
都以某種方式連接到自定義控件和幾個對象,每個對象都占用大量內存,因此我想處置與此TabItem
一起使用的所有對象。
為了使其更清楚並在簡化的情況下為您節省很多代碼:
<UserControl x:Class="myProject.GridFour"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Grid>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<ScrollViewer Height="Auto" Margin="0" Name="scrollViewer11" Width="Auto" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto"></ScrollViewer>
<ScrollViewer Grid.Column="1" Height="Auto" Name="scrollViewer12" Width="Auto" Margin="0" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto"></ScrollViewer>
<ScrollViewer Grid.Row="1"> Height="Auto" Name="scrollViewer21" Width="Auto" Margin="0" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto"></ScrollViewer>
<ScrollViewer Height="Auto" Name="scrollViewer22" Width="Auto" Grid.Column="1" Margin="0" Grid.Row="1" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto"></ScrollViewer>
</Grid>
</UserControl>
現在,我設置相應選項的內容:
GridFour myControl = new GridFour();
myTabItem.Content = myControl;
我還有一些自定義對象,每個對象都包含一個網格,該網格作為內容添加到我的用戶控件的scrollviewer中:
class MyClass
{
internal Grid _grid = new Grid();
internal Image _image = new Image() {Width = Double.NaN, Height = Double.NaN HorizontalAlignment = HorizontalAlignment.Center, VerticalAlignment = VerticalAlignment.Center, Stretch = Stretch.Fill};
//... a lot of variables, data, images and methods...
}
MyClass[] myObject = new MyClass[4];
for(int i = 0; i < 4; i++)
{
myObject[i] = new MyClass();
myObject[i]._grid.Children.Add(_image); //that actually happens when I initialise the object, it is just to show how everything is connected
}
myControl.scrollViewer11.Content = myObject[0]._grid;
myControl.scrollViewer12.Content = myObject[1]._grid;
myControl.scrollViewer21.Content = myObject[2]._grid;
myControl.scrollViewer22.Content = myObject[3]._grid;
現在,當用戶顯然想要關閉列表項時,我也想擺脫myControl和每個對象myObject。 我試圖通過IDisposable對其調用Dispose方法,但始終拋出NullReferenceException,我根本不知道為什么。
我也許應該提到,每個myObject都在Dictionary<string, MyClass>
但是在調用dispose之前,我從那里刪除了該對象。
class MyClass : IDisposable
{
internal Grid _grid = new Grid();
internal Image _image = new Image() {Width = Double.NaN, Height = Double.NaN HorizontalAlignment = HorizontalAlignment.Center, VerticalAlignment = VerticalAlignment.Center, Stretch = Stretch.Fill};
//... a lot of variables, data, images and methods...
public void Dispose()
{
// your custom disposing
_image = null; //or something like that
}
}
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