用命令绑定多个参数 [英] Multiple parameters with Command binding

问题描述

我有命令结合和利用Prism库中的文本块

I have a textblock with command binding and using Prism library.

这是XAML PARTH：

this is the XAML parth:

<TextBlock Margin="0,10,0,0">SocialSecurityNumer:</TextBlock>
<TextBox Name="SSNText" GotFocus="TextBox_GotFocus" Text="{Binding SSN, UpdateSourceTrigger=PropertyChanged}" Margin="0,3,0,0"/>

这是视图模型背后：

And this is the ViewModel behind:

public FindViewModel()
{
    var eventAggregator = ServiceLocator.Current.GetInstance<IEventAggregator>();

    FindCommand = new DelegateCommand(
        () => eventAggregator.GetEvent<SSNChangedEvent>().Publish(SSN),
        () => !string.IsNullOrWhiteSpace(Kennitala)
        );
}

public DelegateCommand FindCommand { get; set; }

private string ssn;
public string SSN
{
    get { return ssn; }
    set
    {
        if (ssn== value)
            return;

        ssn = value;
        RaisePropertyChanged(() => SSN);
        FindCommand.RaiseCanExecuteChanged();
    }
}

这是侦听此事件触发的GridViewModel和火与SSN一个函数作为参数

And this is the GridViewModel that listen for this event trigger and fire up a function with SSN as a parameter

public class GridViewModel : NotificationObject
{
    public GridViewModel()
    {
        var eventAggregator = ServiceLocator.Current.GetInstance<IEventAggregator>();
        eventAggregator.GetEvent<SSNChangedEvent>().Subscribe(GetData);
    }

    public ObservableCollection<Investment> Investments { get; set; }

    private void GetData(string ssn)
    {
        var list = GeniusConnection.GetDataFromWebService(ssn);

        Investments = new ObservableCollection<Investment>(list);

        RaisePropertyChanged(() => Investment);
    }
}

我怎么可以添加其他参数，例如日期时间参数，这混淆了我的部分是：

How can i add another parameter, for example datetime parameter, the part that confuses me is:

FindCommand = new DelegateCommand(
            () => eventAggregator.GetEvent<SSNChangedEvent>().Publish(SSN),
            () => !string.IsNullOrWhiteSpace(Kennitala)
            );

本发布功能只需一个参数并为此我不知道怎样才能轻松地添加多个paramters ??

This Publish function takes just one parameter and therefor i don´t see how i can easily add multiple paramters.??

推荐答案

您应该创建包含要发布所有neccessary参数的一类。

you should create a class that holds all neccessary parameters that you want to publish.

 public class SSNChangedEventParams
 {
     public string SSN{get;set;}
     public DateTime Dt{get;set;}
     ...
 }

和再发布的这个实例类：

and then Publish an instance of this class:

 eventAggregator.GetEvent<SSNChangedEvent>().Publish(new SSNChangedEventParams(){SSN=SSN, Dt = DateTime.Now})

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