c# – 在MVVMCross中将参数从Detail传递给MainViewModel

概述我有两个视图：MainView和DetailView.我有一个要显示的项目列表,当用户选择项目时,我将项目属性传递给DetailViewModel,用户可以更新这些值. 到目前为止一切正常,但我想知道如何将更新的值传递给MainViewModel？ MainViewModel.cs public MainViewModel SelectedItem{ get { return _select 我有两个视图：MainVIEw和DetailVIEw.我有一个要显示的项目列表,当用户选择项目时,我将项目属性传递给Detailviewmodel,用户可以更新这些值.

到目前为止一切正常,但我想知道如何将更新的值传递给Mainviewmodel？

Mainviewmodel.cs

public Mainviewmodel SelectedItem{  get { return _selectedItem; }  set  {    _selectedItem = value;    Showviewmodel<Detailviewmodel>(    new Detailviewmodel.Parameter    {        Date = Date,Age = _selectedItem.Age,category = _selectedItem.category,discount = _selectedItem.discount,}     );    RaisePropertyChanged(() => SelectedItem);  }}

Detailviewmodel.cs

public class Detailviewmodel: Mvxviewmodel{    public double Age { get; set; }    public double category { get; set; }    public double discount { get; set; }    public class Parameter    {        public DateTime Date { get; set; }        public double Age { get; set; }        public int category{ get; set; }        public double discount { get; set; }    }    public voID Init(Parameter param)    {        Age = param.Age;        category = param.category;        discount = param.discount ;    }}

解决方法 在viewmodels之间传递变量的一种方法是基于Messenger的解决方案.

MvvmCross Messenger可以在NuGet中找到.

Mainviewmodel

private Readonly IMvxMessenger _messenger;private Readonly MvxSubscriptionToken _token;public Mainviewmodel(IMvxMessenger messenger) {    _messenger = messenger;    _token = messenger.Subscribe<SelectedItemmessage>(OnMessageReceived);;}private voID OnMessageReceived(SelectedItemmessage obj){    SelectedItem = obj.SelectedItem;}

Detailviewmodel

private Readonly IMvxMessenger _messenger;public Detailviewmodel(IMvxMessenger messenger) {    _messenger = messenger;}public voID YourUpdateMethod() {    var message = new SelectedItemmessage(this,SelectedItem); //SelectedItem assumed it is a viewmodel property.    _messenger.Publish(message,typeof(SelectedItemmessage));}

SelectedItemmessage

public class SelectedItemmessage : MvxMessage{    public SelectedItemmessage(object sender,SelectedItem selectedItem) : base(sender)    {        SelectedItem = selectedItem;    }    public SelectedItem SelectedItem { get; set; }}

请查看http://slodge.blogspot.nl/2013/05/n9-getting-message-n1-days-of-mvvmcross.html以获取MvvmCross Messenges的完整指南.

使用消息中的年龄和类别进行编辑

public SelectedItemmessage(object sender,double age,int category) : base(sender)    {        Age = age;        category = category;    }    public double Age { get; set; }    public int category{ get; set; }}

更改Mainviewmodel OnMessageReceived方法

private voID OnMessageReceived(SelectedItemmessage obj){    Age = obj.Age;    category= obj.category;}

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