如何在 viewmodel 中访问 mvvm 模型中的控件? [英] How can i access a control in mvvm model in viewmodel?

问题描述

我有一个 WPF 窗口，在那个窗口中我有一个网格.

I have a WPF Window, and in that window I have a grid.

我使用 M-V-VM 模型，我想在代码中(在视图模型中)动态地将一个文本框添加到网格中

I use M-V-VM model and I want to add a TextBox to the grid dynamically in code(in viewmodel)

如何访问网格?

推荐答案

使用监督控制器模式.

Use Supervising Controller pattern.

阅读:

此处显示了 CaliburnMicro MVVM 框架的示例实现(适用于所有其他框架 - 或者如果您自己执行 MVVM，则可以手动完成):

Example implementation for CaliburnMicro MVVM framework is shown here (will work same for all other frameworks - or you can do it by hand if you are doing MVVM by yourself):

http://drc.ideablade.com/devforce-2012/bin/view/Documentation/cocktail-tutorial-talk-to-view

示例:

1) 定义接口IView，其中ViewModel (VM) 将与View 使用所需的方法

1) Define interface IView in which ViewModel (VM) will talk to View with the required method(s)

public interface IView 
{
    void AddTextBoxToGrid();
}

2) 从你的 IView 继承 View 后面的代码并实现 IView.AddTextboxToGrid() 方法

2) Inherit code behind View from your IView and implement IView.AddTextboxToGrid() method

public partial class View: IView 
{
    public void AddTextBoxToGrid() 
    {  
        // implement here your custom view logic using standard code behind; 
    }
}

3) 将 IView 类型的属性添加到您的 VM

3) Add a property of type IView to your VM

public class ViewModel 
{
    public IView View { get; set; }
}

4) 将 VM 上的 View 属性设置为 View 的一个实例为 IView例如在后面的代码中:

4) Set View property on VM to an instance of View as IView e.g. in code behind:

 DataContext.View = this as IView; 

或者在 Caliburn 中你可以使用 IScreen.OnViewAttached 覆盖方法)

or in Caliburn you can use IScreen.OnViewAttached override method)

public partial class View: IView 
{
    public View()
    {
        // access you VM by the strategy of your framework or choice - this example is when you store your VM in View's DataContext
        (DataContext as ViewModel).View = this as IView;
    } 

    public void AddTextBoxToGrid() 
    {  
        // implement here your custom view logic using standard code behind; 
    }
}

5) 在你的 VM 调用 IView.AddTextboxToGrid()

5) In your VM call IView.AddTextboxToGrid()

public class ViewModel 
{
    public IView View { get; set; }

    public void AddTextBoxToGrid() 
    {
        if (View == null) return;
        View.AddTextBoxToGrid()
    }
}

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