如何使用wpf和mvvm中的动态菜单获得正确的CommandParameter绑定
我正在WPF应用程序中实现一个动态菜单服务。每个命令都可以或应该有不同的CommandParameters 问题: 使用我在xaml中设置CommandParameter绑定的解决方案,可以从命令DoeSentUpdate获得CanExecute属性 到目前为止我拥有的 我正在使用mvvm light和fody propertychanged 这里是菜单类:如何使用wpf和mvvm中的动态菜单获得正确的CommandParameter绑定,wpf,menu,mvvm-light,fody-propertychanged,wvvm,Wpf,Menu,Mvvm Light,Fody Propertychanged,Wvvm,我正在WPF应用程序中实现一个动态菜单服务。每个命令都可以或应该有不同的CommandParameters 问题: 使用我在xaml中设置CommandParameter绑定的解决方案,可以从命令DoeSentUpdate获得CanExecute属性 到目前为止我拥有的 我正在使用mvvm light和fody propertychanged 这里是菜单类: public class MyMenu : INotifyPropertyChanged { private Observable
public class MyMenu : INotifyPropertyChanged
{
private ObservableCollection<MyMenu> myChildren;
public MyMenu()
{
myChildren = new ObservableCollection<MyMenu>();
}
public string Header { get; set; }
public string Image { get; set; }
public string CommandName { get; set; } //used to set the CommandParameter binding
public ICommand Command { get; set; }
public ObservableCollection<MyMenu> Children {
get
{
return myChildren;
}
private set
{
myChildren = value;
}
}
public event PropertyChangedEventHandler PropertyChanged;
}
然后,我在viewmodel中有一个可绑定属性:
public ObservableCollection<MyMenu> MainMenu
{
get
{
return myMenuService.MainMenu;
}
}
public observetecollection主菜单
{
得到
{
返回myMenuService.main菜单;
}
}
此处命令实现为RelayCommand:
//in the constructor
OpenSelectTestprocedureWindowCommand = new RelayCommand<ShowTestschrittViewParameter>(OpenSelectTestablaufWindow, CanOpenSelectTestablaufWindow);
OpenUserLoginDialogCommand = new RelayCommand<Type>(OpenUserLoginDialog);
private void OpenUserLoginDialog(Type aWindowType)
{
myNavigationService.ShowWindowModal(aWindowType);
}
private bool CanOpenSelectTestablaufWindow(ShowTestschrittViewParameter showTestschrittViewParameter)
{
if (myDataService.CurrentTestProcedure != null)
{
if (myDataService.CurrentTestProcedure.TestProcedureState == Logic.Model.GlobalTypes.TestProcedureState.Running) return false;
}
return new ViewModelLocator().UserLoginDialogViewModel.User.NameIsValid;
}
private void OpenSelectTestablaufWindow(ShowTestschrittViewParameter showTestschrittViewParameter)
{
myNavigationService.ShowTestschrittView(showTestschrittViewParameter);
}
//在构造函数中
OpenSelectTestprocedureWindowCommand=newrelaycommand(OpenSelectTestablaufWindow,CanOpenSelectTestablaufWindow);
OpenUserLoginDialogCommand=新的RelayCommand(OpenUserLoginDialog);
私有void OpenUserLoginDialog(类型aWindowType)
{
myNavigationService.ShowWindowModal(aWindowType);
}
专用bool CANopenSelectTestBlaufWindow(ShowTestschrittViewParameter ShowTestschrittViewParameter)
{
if(myDataService.CurrentTestProcedure!=null)
{
if(myDataService.CurrentTestProcedure.TestProcedureRate==Logic.Model.GlobalTypes.TestProcedureRate.Running)返回false;
}
返回新的ViewModelLocator().UserLoginDialogViewModel.User.NameIsValid;
}
私有void openselectTestBlaufWindow(ShowTestschrittViewParameter ShowTestschrittViewParameter)
{
myNavigationService.ShowTestschrittView(ShowTestschrittView参数);
}
然后在MainView中,我有以下xaml:
<Menu Grid.Row="2" ItemsSource="{Binding MainMenu}" Name="DynamicMenu">
<!--<Menu.ItemTemplate>
<DataTemplate DataType="{x:Type luih:MyMenu}">
<StackPanel>
<Label Content="{Binding Header}"/>
<Image Source="{Binding Image}"/>
</StackPanel>
</DataTemplate>
</Menu.ItemTemplate>-->
<Menu.ItemContainerStyle>
<Style TargetType="{x:Type MenuItem}">
<Setter Property="Header" Value="{Binding Header}"/>
<Setter Property="Command" Value="{Binding Command}"/>
<Setter Property="ItemsSource" Value="{Binding Children}"/>
<Style.Triggers>
<DataTrigger Binding="{Binding CommandName}" Value="OpenUserLoginDialogCommand">
<Setter Property="CommandParameter" Value="{x:Type local:UserLoginDialog}"/>
</DataTrigger>
<DataTrigger Binding="{Binding CommandName}" Value="OpenSelectTestprocedureWindowCommand">
<Setter Property="CommandParameter" Value="{x:Type local:UserLoginDialog}"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Menu.ItemContainerStyle>
</Menu>
注意。xaml中的CommandParameter绑定类型当前不正确。这是另一个问题,我会自己解决。但出于测试目的,它应该可以工作。它将给我一个例外,因为错误的类型
但是,当我用Style.Trigger和DataTrigger绑定CommandParameter时,CanExecute属性在运行时不再发送更新。当我评论这一部分时,一切都很好。但是我没有命令参数
欢迎提供任何帮助和建议。我发现了这个问题 mvvm light的RelayCommand评估CanExecute函数的参数类型。这必须是正确的声明类型或null 因此,出于测试目的,我必须如下设置绑定:
<Style TargetType="{x:Type MenuItem}">
<Setter Property="CommandParameter" Value="{x:Null}"/>
</Style>
<Menu Grid.Row="2" ItemsSource="{Binding MainMenu}" Name="DynamicMenu">
<!--<Menu.ItemTemplate>
<DataTemplate DataType="{x:Type luih:MyMenu}">
<StackPanel>
<Label Content="{Binding Header}"/>
<Image Source="{Binding Image}"/>
</StackPanel>
</DataTemplate>
</Menu.ItemTemplate>-->
<Menu.ItemContainerStyle>
<Style TargetType="{x:Type MenuItem}">
<Setter Property="Header" Value="{Binding Header}"/>
<Setter Property="Command" Value="{Binding Command}"/>
<Setter Property="ItemsSource" Value="{Binding Children}"/>
<Style.Triggers>
<DataTrigger Binding="{Binding CommandName}" Value="OpenUserLoginDialogCommand">
<Setter Property="CommandParameter" Value="{x:Type local:UserLoginDialog}"/>
</DataTrigger>
<DataTrigger Binding="{Binding CommandName}" Value="OpenSelectTestprocedureWindowCommand">
<Setter Property="CommandParameter" Value="{x:Type local:UserLoginDialog}"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Menu.ItemContainerStyle>
</Menu>
<Style TargetType="{x:Type MenuItem}">
<Setter Property="CommandParameter" Value="{x:Null}"/>
</Style>