WPF:ComboBox最大项目 [英] WPF: ComboBox Max Items
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问题描述
我有一个WPF应用程序,其中有一个组合框
I have a WPF application in which I have a combobox
<ComboBox Margin="2,0,5,0" Width="178" ItemsSource="{Binding Animateur}" DisplayMemberPath="fsign_nom" SelectedIndex="0" >
<ComboBox.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel />
</ItemsPanelTemplate>
</ComboBox.ItemsPanel>
</ComboBox>
ItemsSource
包含20100个项目,是我尝试打开组合框选择一个元素时,应用程序被阻止。
the ItemsSource
contains 20100 items , the problem is when I try to open the combobox to select an element, the application were blocked .
viewmodel类
_service.GetAnimateur((item, error) =>
{
if (error != null)
{
// TODO : traitement d'erreur
}
else
{
_Animateur.Clear();
item.ForEach(Elem =>
{
_Animateur.Add(Elem);
});
}
});
Asynchrounous方法:
public async void GetAnimateur(Action<List<fiche>, Exception> callback)
{
try
{
Task<List<fiche>> data = (Task<List<fiche>>)Task.Run(
() =>
{
DataEntities _db = new DataEntities();
_db.Configuration.LazyLoadingEnabled = false;
var dpcs = _db.fiche;
return new List<fiche>(dpcs);
});
var result = await data;
callback(result, null);
}
catch (Exception ex)
{
callback(null, ex);
}
}
我看过这个文章,所以我添加了虚拟化部分,但我有相同的结果。
I have seen this article so I added the virtualization part, but I got the same result.
所以我需要知道:
- 如何解决这个问题?
-
ItemsSource
中的项目数量上限是多少?
- How can I fix this problem?
- What is the max number of items in the
ItemsSource
?
推荐答案
尝试测试没有异步部分
这对我100万行非常有用
Try testing without the async part
This works fine for me with 1 million rows
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<ComboBox Grid.Row="0" ItemsSource="{Binding Path=Lots}">
<ComboBox.ItemsPanel>
<ItemsPanelTemplate>
<VirtualizingStackPanel />
</ItemsPanelTemplate>
</ComboBox.ItemsPanel>
</ComboBox>
<ListBox Grid.Row="1" ItemsSource="{Binding Path=Lots}"
VirtualizingStackPanel.IsVirtualizing="True"/>
</Grid>
private List<string> lots;
public List<string> Lots
{
get
{
if (lots == null)
{
lots = new List<string>();
for (int i = 0; i < 1000000; i++) lots.Add("lot " + i.ToString());
}
return lots;
}
}
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