任何人都可以從這段代碼變戲法之前Items集合必須是空的，爲什麼的ItemsSource線將得到一個這是爲什麼XAML得到的錯誤：使用的ItemsSource

Items collection must be empty before using ItemsSource.

錯誤？我發現的大多數解決方案都指向了錯誤組合的XAML，例如一個額外的元素等，我似乎沒有。當我拿出

ItemsSource="{Binding Customers}"

它運行時沒有錯誤（但當然不顯示我的客戶名單）。

客戶正是如此定義視圖模型，並在其3個CustomerViewModels：

Customer[] customers = Customer.GetCustomers(); 
IEnumerable<CustomerViewModel> customersViewModels = customers.Select(c => new CustomerViewModel(c)); 
this.Customers = new ReadOnlyCollection<CustomerViewModel>(customersViewModels.ToArray());

的在哪裏看有什麼建議？

<UserControl x:Class="TestCommandSink123.View.CustomersView" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:local="clr-namespace:TestCommandSink123" 
    xmlns:view="clr-namespace:TestCommandSink123.View" 
    xmlns:vm="clr-namespace:TestCommandSink123.ViewModel" 
    xmlns:sink="clr-namespace:TestCommandSink123.CommandSinkClasses" 
    sink:CommandSinkBinding.CommandSink="{Binding}" 
    > 

    <UserControl.CommandBindings> 
     <sink:CommandSinkBinding Command="vm:CustomersViewModel.CloseAllCustomersCommand"/> 
    </UserControl.CommandBindings> 

    <DockPanel> 
     <ItemsControl 
      DockPanel.Dock="Bottom" ItemsSource="{Binding Customers}"> 
      <ItemsControl.ItemTemplate> 
       <DataTemplate> 
        <view:CustomerView/> 
       </DataTemplate> 
      </ItemsControl.ItemTemplate> 
      <Button 
       Command="vm:CustomersViewModel.CloseAllCustomersCommand" 
       Content="Close All" 
       Margin="0,0,0,8" 
       /> 
     </ItemsControl> 

    </DockPanel> 
</UserControl>

答：

我的確有畸形XAML，就忽視它，按鈕應該是ItemsControl的外：

<ItemsControl 
    DockPanel.Dock="Bottom" ItemsSource="{Binding Customers}"> 
    <ItemsControl.ItemTemplate> 
     <DataTemplate> 
      <view:CustomerView/> 
     </DataTemplate> 
    </ItemsControl.ItemTemplate> 
</ItemsControl> 
<Button 
    Command="vm:CustomersViewModel.CloseAllCustomersCommand" 
    Content="Close All" 
    Margin="0,0,0,8" 
    />

來源

2009-04-22 Edward Tanguay

剛剛提的格式不正確的XAML幫助，如果你忘記了你的控件的XML元素內的任何文字我 – stambikk 2017-10-06 00:19:35