我正在尝试执行基于列表视图项目数据的方法。除此之外,只有当列表视图项的“CanExecute”方法返回 true 时,才应启用触发命令的按钮。
“MyCommand”和“CanExecute”这两种方法都包含在我的 ViewModel 中。
不幸的是,我不确定如何将项目信息正确传递给这两种方法,以符合 PRISM 6 框架。
所以我的第一个方法是这样做:
Model
public class MyModel
{
public string Name { get; set; }
public string Version { get; set; }
public int Identifier { get; set; }
}
视图模型
public class MyViewModel : BindableBase
{
private ObservableCollection<MyModel> _models = new ObservableCollection<MyModel>();
public ObservableCollection<MyModel> Models
{
get { return _models; }
set { SetProperty(ref _models, value); }
}
public DelegateCommand VerifyCommand { get; set; }
public MyViewModel()
{
//Add test data
for (int i = 0; i < 5; i++)
{
MyModel model = new MyModel();
model.Name = "Random Text";
model.Version = "Random Text";
model.Identifier = i;
Models.Add(model);
}
//Doesn't work, because I don't reference to "Models"
//How to do that?
VerifyCommand = new DelegateCommand(DoCommand, CanExecute).ObservesProperty<string>(() => Name).ObservesProperty<string>(() => Version);
}
private bool CanExecute()
{
//Obviously this doesn't work, because "Version" and "Name"
//don't belong to the selected "Models" item of the listview
//What is the "bridge", to know which item of Models was clicked (button)
return !String.IsNullOrWhiteSpace(Version) && !String.IsNullOrWhiteSpace(Name);
}
private void DoCommand()
{
//Do something special
}
}
View
<ListView ItemsSource="{Binding Models}">
<ListView.ItemTemplate>
<DataTemplate>
<Grid Height="Auto" Margin="0,0,0,10">
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<TextBox Grid.Row="0" Tag="VERSION" Text="{Binding Version, UpdateSourceTrigger=PropertyChanged}" />
<TextBox Grid.Row="1" Tag="NAME" Text="{Binding Name, UpdateSourceTrigger=PropertyChanged}" />
<Button Command="{Binding ElementName=root, Path=DataContext.VerifyCommand}" Content="Verify" Grid.Row="2">
</Grid>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
View 和 ViewModel 之间的链接是通过使用以下方式完成的:
prism:ViewModelLocator.AutoWireViewModel="True"
在我看来(这有效)。
总结来说:
它是如何工作的,PRISM 符合 1. 仅当 CanExecute 为 true 时才启用项目按钮,2. 执行“DoCommand”方法并将项目信息传递给该方法(按钮的根元素 -> 在本例中为 ListViewItem (MyModel )。
任何帮助将不胜感激。