从ShowDialog获取结果，而无需求助于背后的代码 [英] Getting result from ShowDialog without resorting to code behind

问题描述

我正在从此问题的出色答案中实施代码

I'm implementing code from the excellent answer to this question WPF + Castle Windsor + MVVM: Locator-DataContext. I'm not sure how to get the value from ShowDialog() though without resorting to code behind (which breaks testability), anyone have any ideas?

我在MVVM Light Messenger类中使用了该类，并且运行良好，但是需要使用Service Locator反模式.

I was using this class with the MVVM Light Messenger class and it was working fine, but entails using the Service Locator anti-pattern.

编辑

我当前无法使用的代码是

The current code I have that isn't working is

DataSourcePicker.xaml.cs

DataSourcePicker.xaml.cs

public DataSourcePicker(IDataSourcePickerViewModel viewModel)
{
    InitializeComponent();
    _viewModel = viewModel;
    DataContext = viewModel;
    Closed += (s, a) => RaiseDismissed();
}

public event Action OnDismissed;

private void RaiseDismissed()
{
    if (OnDismissed != null)
        OnDismissed()
}

在DataSourcePicker.xaml

in DataSourcePicker.xaml

<Button IsDefault="True" .../>

在MainViewModel.cs

in MainViewModel.cs

public void NewDataSource()
{
    var viewModel = _dspViewModelFactory.ResolveDataSourcePickerViewModel();
    var view = _dspFactory.ResolveDataSourcePicker(viewModel);
    view.OnDismissed += () => NewDataSourceImplementation(viewModel);
    view.ShowDialog();
}

我需要一些方法来在用户单击按钮时将DataSourcePickerViewModel的IsAccepted属性设置为true

I need some way to set the IsAccepted property on the DataSourcePickerViewModel to true when the user clicks the button

推荐答案

由于您忽略了显示"ShowDialog"的实现或解释了DataSourcePicker在应用程序中的显示方式，因此很难给您一个清晰的提示.解决方案;因此，根据您对DataSourcePicker的实现，有两种选择:

Because you have neglected to show your implementation of "ShowDialog" or explain how your DataSourcePicker shows up in the application, it is difficult to give you a clear solution; So, here are two options depending on your implementation of DataSourcePicker:

在您的DataSourcePicker.ShowDialog方法仅调用MessageBox.Show的情况下，您的解决方案很简单.

In the unlikely event that your DataSourcePicker.ShowDialog method simply invokes MessageBox.Show, your solution is simple.

    public void NewDataSource()
    {
        var viewModel = _dspViewModelFactory.ResolveDataSourcePickerViewModel();
        var view = _dspFactory.ResolveDataSourcePicker(viewModel);
        var result = view.ShowDialog();
        if (result.HasValue)
        {
            viewModel.IsAccepted = result.Value;
        }
    }

但是，如果您已经将DataSourcePicker实现为自定义的模态"对话框窗口，或者在执行ShowDialog之后没有立即关闭对话框窗口，则解决方案将变得更加复杂.

However, if you have implemented your DataSourcePicker as a custom Modal dialog window, or you do not close the dialog window immediately after ShowDialog has executed, the solution becomes more complex.

在这种情况下，您将必须在视图模型中添加ICommand.

In this scenario, you will have to add an ICommand to your viewmodel.

class DataSourcePickerViewModel : IDataSourcePickerViewModel
{
    public bool IsAccepted { get; set; }
    public ICommand NewDataSourceCommand { get; private set; }

    public DataSourcePickerViewModel()
    {
        NewDataSourceCommand = new RelayCommand(() =>
        {
            IsAccepted = true;
        });
    }
}

然后，您将必须使用以下内容更新DataSourcePickerView:

Then, you will have to update your DataSourcePickerView with:

<Button Command="{Binding NewDataSourceCommand}"
        Content="Close"/>

否则，您将需要使用以下解决方案之一将命令绑定到事件:

Otherwise, you will need to Use one of the following solutions for binding commands to events:

• MVVM Light-EventToCommand
• MSDN-EventToCommand
• Marlon Grechs AttachedCommandBehavior

• MVVM Light - EventToCommand
• MSDN - EventToCommand
• Marlon Grechs AttachedCommandBehavior

然后，您将像这样更新视图(如果使用AttachedCommandBehavior库):

Then, you would update the view like so (If using the AttachedCommandBehavior library):

<ModalControl x:Class="_24318313.DataSourcePicker"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
              xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
              xmlns:local="clr-namespace:_24318313"
              mc:Ignorable="d" d:DataContext="{d:DesignInstance local:DataSourcePickerViewModel}"
              local:CommandBehavior.Event="Close"
              local:CommandBehavior.Command="{Binding NewDataSourceCommand}"
              d:DesignHeight="300" d:DesignWidth="300"/>

如果您认为这不能解决您的问题，请告知我们，我们将根据您的反馈进行更新；否则，请将答案标记为已接受.

If you feel this doesn't solve you issue, please let me know and I will update in response to your feedback; Otherwise, please mark an answer as accepted.

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