C#中的数据绑定问题

我试图更好地了解.net中的数据绑定如何工作.我正在查看this条文章,然后想到了以下代码：

public partial class Form1 : Form//, INotifyPropertyChanged
{
    public event PropertyChangedEventHandler MyTextChanged;

    [System.ComponentModel.Bindable(true)]
    public string MyText
    {
        get { return textBox1.Text; }
        set 
        {
            textBox1.Text = value;
            if (MyTextChanged != null)
                MyTextChanged(this, new PropertyChangedEventArgs("MyText"));
        }
    }

    MyClass myClass { get; set; }

    public Form1()
    {
        InitializeComponent();
        myClass = new MyClass();
        Binding binding = new Binding("MyText", myClass, "Dic");
        binding.Parse += new ConvertEventHandler(binding_Parse);
        binding.Format += new ConvertEventHandler(binding_Format);
        DataBindings.Add(binding);
        myClass.AddStuff("uno", "UNO");
    }

    void OnMyTextChanged(PropertyChangedEventArgs e)
    {
        if (MyTextChanged != null) MyTextChanged(this, e);
    }

    void binding_Format(object sender, ConvertEventArgs e)
    {
        if (e.Value is Dictionary<string, string>)
        {
            Dictionary<string, string> source = (Dictionary<string, string>)e.Value;
            e.Value = source.Count.ToString();
        }
    }

    void binding_Parse(object sender, ConvertEventArgs e)
    {
        MessageBox.Show(e.DesiredType.ToString());
    }

    private void changemyClassButton_Click(object sender, EventArgs e)
    {
        myClass.AddStuff(myClass.Dic.Count.ToString(), "'" + myClass.Dic.Count.ToString() + "'");
    }

    private void changeMyTextButton_Click(object sender, EventArgs e)
    {
        MyText = "1234";
    }
}

public class MyClass : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public Dictionary<string, string> Dic { get; set; }

    public MyClass()
    {
        Dic = new Dictionary<string, string>();
    }

    public void AddStuff(string key, string value)
    {
        Dic.Add(key, value);
        if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Dic"));
    }
}

我试图将MyText绑定到myClass.问题在于,永远不会调用函数binding_Parse.我知道我可能可以直接将textBox1.Text绑定到myClass,或者可能有成千上万种其他方法可以完成我想做的事情,但这只是一种实践；我试图了解更好的数据绑定.因此,我想将自定义对象绑定到自定义属性,以便可以从头到尾看到该过程.自定义对象是myClass,而自定义属性是MyText.我已经尝试了各种变体,例如实现INotifyPropertyChanged,但是我无法调用binding_Parse(我希望在调用changeMyTextButton_Click时会调用它).我想念什么吗？

编辑：
简而言之：我想编写一个带有属性字符串MyText的用户控件,然后用户可以将其绑定到其他对象,就像将TextBox的Text属性绑定到其他对象一样.因此,我不想将控件的属性绑定到对象,而是想编写具有属性的控件,然后用户可以将其绑定到对象.

解决方法:

好吧,我想通了,以防万一有人遇到同样的问题.我必须创建一个名为MyTextChanged的事件处理程序,以使Binding知道MyText正在更改,并将Bindings DataSourceUpdateMode属性设置为OnPropertyChanged.使用这个简单的原理,我可以将屏幕上的像素绑定到宇宙的其余部分:).这是代码：

public partial class Form1 : Form
{
    public event EventHandler MyTextChanged;

    [Bindable(true)]
    public string MyText
    {
        get { return textBox1.Text; }
        set 
        {
            if (textBox1.Text != value)
            {
                textBox1.Text = value;
                OnMyTextChanged();
            }
        }
    }

    MyClass myClass { get; set; }

    public Form1()
    {
        InitializeComponent();
        myClass = new MyClass();
        Binding binding = new Binding("MyText", myClass, "Dic");
        binding.DataSourceUpdateMode = DataSourceUpdateMode.OnPropertyChanged;
        binding.Parse += new ConvertEventHandler(binding_Parse);
        binding.Format += new ConvertEventHandler(binding_Format);
        DataBindings.Add(binding);
        myClass.AddStuff("uno", "UNO");
    }

    void OnMyTextChanged()
    {
        if (MyTextChanged != null) MyTextChanged(this, EventArgs.Empty);
    }

    void binding_Format(object sender, ConvertEventArgs e)
    {
        if (e.Value is Dictionary<string, string>)
        {
            Dictionary<string, string> source = (Dictionary<string, string>)e.Value;
            e.Value = source.Count.ToString();
        }
    }

    void binding_Parse(object sender, ConvertEventArgs e)
    {
        MessageBox.Show(e.DesiredType.ToString());

    }

    private void changemyClassButton_Click(object sender, EventArgs e)
    {
        myClass.AddStuff(myClass.Dic.Count.ToString(), "'" + myClass.Dic.Count.ToString() + "'");
    }

    private void changeMyTextButton_Click(object sender, EventArgs e)
    {
        MyText = "1234";
    }
}

public class MyClass : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    public Dictionary<string, string> Dic { get; set; }

    public MyClass()
    {
        Dic = new Dictionary<string, string>();
    }

    public void AddStuff(string key, string value)
    {
        Dic.Add(key, value);
        if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Dic"));
    }
}

标签：data-binding,c,net,winforms
来源： https://codeday.me/bug/20191209/2095997.html