我正在使用 mvvm 模式,我很难从 ListView 的 ItemContainerStyle 中弄清楚如何在 ContextMenu 上设置 DataContext。
我也不明白为什么 ListView.ContextMenu 和 ListView 的 GridView.ColumnHeaderContextMenu 可以从我的 View 模型中看到属性和命令,但 ListView.ItemContainerStyle 中的 ContextMenu 却不能。
错误
System.Windows.Data 错误:40:BindingExpression 路径错误:在“对象”“货币”(HashCode = 43406546)上找不到“AddMenuItem”属性。绑定(bind)表达式:路径=添加菜单项; DataItem='货币' (HashCode=43406546);目标元素是'ContextMenu'(名称='');目标属性是“ItemsSource”(类型“IEnumerable”)
查看
<!-- Removed styles for clarity. -->
<UserControl>
<!-- Add ElementSpy to the UserControl’s rsources -->
<UserControl.Resources>
<framework:ElementSpy x:Key="spy" />
</UserControl.Resources>
<ListView ItemsSource="{Binding Currency}">
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="ContextMenu">
<Setter.Value>
<!-- 'AddMenuItem' property not found on 'object' 'Currency' -->
<!-- ContextMenu ItemsSource="{Binding AddMenuItem}" / -->
<!-- Use the ElementSpy resource -->
<ContextMenu ItemsSource="{Binding Source={StaticResource spy}, Path=Element.DataContext.AddMenuItem}" />
</Setter.Value>
</Setter>
</Style>
</ListView.ItemContainerStyle>
<ListView.ContextMenu>
<!-- Works -->
<ContextMenu ItemsSource="{Binding EditMenuItem}" />
</ListView.ContextMenu>
<ListView.View>
<GridView>
<GridView.ColumnHeaderContextMenu>
<!-- Works -->
<ContextMenu ItemsSource="{Binding SortMenuItem}" />
</GridView.ColumnHeaderContextMenu>
<GridViewColumn Header="Code"
DisplayMemberBinding="{Binding Path=Code}" />
<GridViewColumn Header="Description"
DisplayMemberBinding="{Binding Path=Description}" />
<GridViewColumn Header="Exchange Rate"
DisplayMemberBinding="{Binding Path=ExchangeRate}" />
</GridView>
</ListView.View>
</ListView>
</UserControl>
后面的代码
[Export(ViewNames.CurrencyMasterView, typeof(IMasterView))]
[PartCreationPolicy(CreationPolicy.Shared)]
public partial class CurrencyMasterView
: UserControl, IMasterView
{
public CurrencyMasterView()
{
InitializeComponent();
}
[Import]
private MasterViewModel ViewModel
{
set
{
this.DataContext = value;
}
}
}
查看型号
[Export(typeof(MasterViewModel))]
[PartCreationPolicy(CreationPolicy.NonShared)]
public class MasterViewModel
: ViewModelBase
{
[ImportingConstructor]
public MasterViewModel(IGeneralController generalController, IRegionManager regionManager)
{
}
public ObservableCollection<Currency> Currency
{
get
{
return this.currency;
}
set
{
if (this.currency != value)
{
this.currency = value;
this.RaisePropertyChanged(() => this.Currency);
}
}
}
public List<MenuItemMvvm> SortMenuItem
{
get
{
return this.CreateSortMenuItem();
}
}
public List<MenuItemMvvm> EditMenuItem
{
get
{
return this.CreateEditMenuItem();
}
}
public List<MenuItemMvvm> AddMenuItem
{
get
{
return this.CreateAddMenuItem();
}
}
private List<MenuItemMvvm> CreateEditMenuItem()
{
var menu = new List<MenuItemMvvm>();
menu.Add(new MenuItemMvvm("_Edit")
{
Command = this.EditCommand,
Icon = new Image
{
Source = new BitmapImage(new Uri("pack://application:,,,/POS.Modules.Core;component/Resources/Images/16X16/Edit.png"))
}
});
menu.Add(new MenuItemMvvm("_Duplicate")
{
Command = this.DuplicateCommand,
Icon = new Image
{
Source = new BitmapImage(new Uri("pack://application:,,,/POS.Modules.Core;component/Resources/Images/16X16/Copy.png"))
}
});
menu.Add(new MenuItemMvvm("_Delete")
{
Command = this.DeleteCommand,
Icon = new Image
{
Source = new BitmapImage(new Uri("pack://application:,,,/POS.Modules.Core;component/Resources/Images/16X16/Delete.png"))
}
});
return menu;
}
// Other methods removed for clarity
}
最佳答案
这个问题帮助我弄清楚了。
WPF MenuItem.Command binding to ElementName results to System.Windows.Data Error: 4 : Cannot find source for binding with reference
我为其他遇到此问题的人更新了源代码。
为了快速引用,这就是我所做的。
添加 Josh Smith 的 ElementSpy 类。 Enable ElementName Bindings with ElementSpy
将 ElementSpy 添加到 UserControl 的 rsources。
<UserControl.Resources>
<framework:ElementSpy x:Key="spy" />
</UserControl.Resources>
然后绑定(bind)到资源并使用 Element 属性绑定(bind)到 DataContext 和您选择的属性。
<ContextMenu ItemsSource="{Binding Source={StaticResource spy}, Path=Element.DataContext.AddMenuItem}" />
关于wpf - 从 ListView 的 ItemContainer 为 ContextMenu 设置 DataContext?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/5545370/