winform class 中所有子属性的 propertyChanged 更新问题

Question

我实现了一个模型 class 并希望在修改对象时为所有子属性引发 PropertyChanged 事件。但是我发现它不起作用。当我按下按钮时，标签的文本不是 changed.Does 我错过了什么？我从 MSDN 得到这个 -"The PropertyChanged event can indicate all properties on the object have changed by using either null or String.Empty as the property name in the PropertyChangedEventArgs." 平台是 .net framework 4.0 和 VS2015

   public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        Model = new Model()
        {
            data = new User()
            {
                Name = "test"
            }
        };
        label1.DataBindings.Add("Text", Model.data, "Name", false, DataSourceUpdateMode.OnPropertyChanged);
    }
    private Model model;
    public Model Model
    {
        get
        {
            return this.model;
        }
        set
        {
            model = value;
        }
    }

    private void button1_Click(object sender, EventArgs e)
    {
        User temp = new User()
        {
            Name = "test1"
        };
        Model.data = temp;
    }
}

public class NotifyPropertyChanged : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }
    protected bool SetField<T>(ref T field, T value, string propertyName = null)
    {
        if (EqualityComparer<T>.Default.Equals(field, value)) return false;
        field = value;
        OnPropertyChanged(propertyName);
        OnPropertyChanged(null);
        return true;
    }
}
public class Model : NotifyPropertyChanged
{
    private User m_data;
    public User data
    {
        get { return m_data; }
        set
        {
            SetField(ref m_data, value,"data");
        }
    }
}
public class User : NotifyPropertyChanged
{
    private string name;
    public string Name
    {
        get { return this.name; }
        set
        {
            SetField(ref name, value, "Name");
        }
    }
    private string tel;
    public string Tel
    {
        get { return this.tel; }
        set
        {
            SetField(ref tel, value, "Tel");
        }
    }
}

Answer 1

您的问题是您对 Model.data 的绑定，但后来为它分配了一个新值。
因此，绑定监视的实例不再被使用。

您有 2 个选择：

第一个：不要创建新的 User，只需将其更改为 Name:

private void button1_Click(object sender, EventArgs e)
{
    Model.data.Name = "test1";
}

或者，如果您确实需要支持两种情况（创建和分配），那么您必须将绑定更改为 Model 并从 data.Name:[=25= 中获取文本]

label1.DataBindings.Add("Text", Model, "data.Name", false, 
                        DataSourceUpdateMode.OnPropertyChanged);

和Model中User属性的set部分到此：

set
{
    SetField(ref m_data, value, "data");
    this.data.PropertyChanged += (sender, args) => this.OnPropertyChanged("data");
}

因此，这将在数据上创建一个 PropertyChanged，如果 data.Name 已更改，那么如果 data 属性本身已 set

winform class 中所有子属性的 propertyChanged 更新问题

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