改变模型

Question

想象一个简单的UserControl，其中包含一个TextBox（CustomerName）和两个按钮（Save / Cancel）。

此UserControl位于具有两个以上按钮的父控件中（PreviousCustomer / NextCustomer）

问题是我不知道将模型传递给演示者的位置。我是否通过视图构造函数？如果模型更改（单击PreviousCustomer / NextCustomer），该怎么办？我每次都要创建一个新视图吗？如果UserControl与许多孩子很复杂，这似乎很浪费。我可以在视图和演示者中实现UpdateModel方法，还是不正确？

这是我的代码：

public interface IModel
{
    string CustomerName { get; set; }
}

public class Presenter
{
    private IView _view;
    private IModel _model;

    public Presenter(IView view, IModel model)
    {
        _view = view;
        _model = model;
        _view.CustomerName = _model.CustomerName;
    }

    public void Save()
    {
        _model.CustomerName = _view.CustomerName;
    }

    public void Cancel()
    {
        _view.CustomerName = _model.CustomerName;
    }

    public void UpdateModel(IModel newModel)
    {
        _model = newModel;
        _view.CustomerName = _model.CustomerName;
    }
}

public interface IView
{
    string CustomerName { get; set; }
}

public class View : UserControl, IView
{
    private Presenter _presenter;

    public string CustomerName
    {
        get { return CustomerNameEditBox.Text; }
        set { CustomerNameEditBox.Text = value; }
    }

    //Is this the right place to pass in the model?
    public View(IModel model)
    {
        _presenter = new Presenter(this, model);
    }

    private void SaveButton_Click(object sender, EventArgs e)
    {
        _presenter.Save();
    }

    private void CancelButton_Click(object sender, EventArgs e)
    {
        _presenter.Cancel();
    }

    public void UpdateModel(IModel newModel)
    {
        _presenter.UpdateModel(newModel);
    }
}

编辑：如下面的评论中所述，我认为最好让视图完全愚蠢，对演示者或模型一无所知。这是我修改后的代码。

型号：

public interface IModel
{
    string CustomerName { get; set; }
}

public class Model : IModel
{
    public string CustomerName { get; set; }

    public Model(string name)
    {
        CustomerName = name;
    }
}

查看：

public interface IView
{
    event EventHandler SaveClick;
    event EventHandler CancelClick;
    string CustomerName { get; set; }
}

public class View : UserControl, IView
{
    public event EventHandler SaveClick
    {
        add { SaveButton.Click += value; }
        remove { SaveButton.Click -= value; }
    }

    public event EventHandler CancelClick
    {
        add { CancelButton.Click += value; }
        remove { CancelButton.Click -= value; }
    }

    public string CustomerName
    {
        get { return CustomerNameEditBox.Text; }
        set { CustomerNameEditBox.Text = value; }
    }
}

主讲人：

public class Presenter
{
    private IView _view;
    private IModel _model;

    public Control View
    {
        get { return (Control)_view; } 
    }

    public Presenter(IView view, IModel model)
    {
        _view = view;
        _view.SaveClick += new EventHandler(_view_SaveClick);
        _view.CancelClick += new EventHandler(_view_CancelClick);
        _model = model;
        _view.CustomerName = _model.CustomerName;
    }

    void _view_SaveClick(object sender, EventArgs e)
    {
        _model.CustomerName = _view.CustomerName;
    }

    void _view_CancelClick(object sender, EventArgs e)
    {
        _view.CustomerName = _model.CustomerName;
    }

    public void ChangeModel(IModel newModel)
    {
        _model = newModel;
        _view.CustomerName = _model.CustomerName;
    }
}

用法：

public class MainProgram : Form
{
    public void ArbitraryMethod()
    {
        //Create a new model object
        IModel model1 = new Model("test1");

        //Create the presenter with the model and any view implementing IView
        Presenter presenter = new Presenter(new View(), model1);

        //Add the view to a panel control in this form
        mainPanel.Controls.Add(presenter.View);

        //Change the model
        IModel model2 = new Model("test2");
        presenter.ChangeModel(model2);
    }
}

Answer 1

如果您的设计是MVP（模型视图展示器），则应在演示者中创建模型。这就是这种模式背后的想法。 视图与演示者进行通信，演示者为他提供了所需的所有方法，属性和事件。 在您的示例中，您还决定创建模型。你可以这样做，但请从视图中隐藏它。 与您的示例相关，删除构造函数中的IModel参数，然后在代码中创建一个新参数。

考虑通过方法设置视图更改（_view.SetName（“me”）。这可以让您以后的生活更轻松。

无需创建新的winforms表单。也许，我在这里不明白你的观点..

更新

看一下下面的例子。您有视图，演示者和模型的接口（基于您的代码）。我刚刚将IModel重命名为ICustomer以明确我的观点。演示者创建一个模型，用于执行一些I / O操作，并获取一个视图界面，​​用于更新窗口或界面后面的任何内容。

public interface IView
{
    public string CustomerName { get; set; }
}

public interface ICustomer
{
    string CustomerName { get; set; }
}

public interface IModel
{
    void Save(ICustomer entity);
    void Update(ICustomer entity);
    ICustomer Create();
}


public class Customer : ICustomer
{
    public string CustomerName {get;set;}

}

public class MyModel : IModel
{

    public void Save(ICustomer entity)
    {
        //Do something here..
    }

    public void Update(ICustomer entity)
    {
        //Do something here..
    }

    public ICustomer Create()
    {
        return new Customer();
    }
}

public class Presenter
{
    private IView _view;
    private ICustomer _entity;
    private IModel _model = new MyModel();

    public Presenter(IView view)
    {
        _view = view;
        _model = new MyModel();
        _entity = _model.Create();

        _view.CustomerName = _entity.CustomerName;
    }

    public void Save()
    {
        _model.Save(_entity);
    }

    public void Cancel()
    {
        _entity = _model.Create();
    }

    public void UpdateModel(ICustomer customer)
    {
        _model.Update(customer);
        _view.CustomerName = customer.CustomerName;
    }
}