MVVM 理解问题 [英] MVVM Understanding Issues

问题描述

我对 mvvm 的问题列表，您不需要自己回答，总是感谢能帮助我进一步的链接:

A list of my questions towards mvvm, you don't need to answer on your own, links which help me further are always appreciated:

1. 如果我有一个 Mainpage.xaml 文件并且我使用的是视图模型类，那么 Mainpage.xaml.cs 文件中应该包含哪些代码?没有什么?

1. If I have a Mainpage.xaml file and I'm using a viewmodelclass which code should be in the Mainpage.xaml.cs file? Nothing?

那段代码是否应该在 Mainpage.xaml.cs 文件中:

Should that piece of code be in the Mainpage.xaml.cs file:

Viewmodel base = new Viewmodel();

Viewmodel base = new Viewmodel();

如果我实现了 ICommands，我该如何访问 Mainpage.xaml 上的 textbox.text?

If I implement ICommands how can I access for example a textbox.text on the Mainpage.xaml?

推荐答案

1. 理想情况下，是的.但在大多数情况下很难遵循

2. 并非在所有情况下.如果你的 ViewModel 的构造函数不接受参数，你可以用 xaml 编写它:

1. Ideally, yes. But in most of cases it's hard to follow

2. Not in every case. If your ViewModel's constructor does not accept arguments, you can write it in xaml:

<Window.Resources>
    <local:ViewModel x:Key="viewModel" /> <!-- this row will automatically create instance of ViewModel class-->
</Window.Resources>

如果视图模型类接受参数，那么是的，您必须编写:

If view model class accepts arguments, then yes, you will have to write:

ViewModel base = new Viewmodel(yourArgs);
this.DataContext = base;

在代码隐藏中.

1. 如果你想跟着MVVM，把TextBox的Text属性绑定到Viewmodel属性:

1. If you want to follow MVVM, bind TextBox's Text property to Viewmodel property:

<TextBox Text="{Binding MyText}" />

在 ViewModel 中:

and in ViewModel:

private string _myText;
public string MyText
{
    get { return _myText; }
    set 
    {
        if (_myText != value)
        {
            _myText = value;
            // NotifyPropertyChanged("MyText"); if needed
        }
    }
}

然后你可以使用 RelayCommand 或 DelegateCommand(谷歌它)来操作你在 ViewModel 中的 TextBox 的文本.

Then you could use RelayCommand or DelegateCommand (google it) to operate with text of your TextBox inside ViewModel.

1. 是的.Command 还允许将参数传递给 ICommand(例如，当您将使用 RelayCommand 时)

希望能有所帮助.

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