windows 表单组合框中的复杂数据绑定

Question

我在处理 windows 形式的数据绑定时遇到了麻烦。我有两个 classes，一个是 Project，另一个是 Update。现在所有的项目对象都有一个更新列表并且它被绑定到一个组合框，但是当用户更改选择时需要 display/bind 更新对象的属性到另一个控件。但是当用户更改选择时，不会按预期更新。请帮我解决这个问题..

Screenshot

查看我的 class 和下面的代码，

public class Project
{
    private int _id;
    private string _name;

    public Project(int id, string name)
    {
        _id = id;
        _name = name;

        ReadUpdates();
    }

    public List<Update> AvailableUpdates { get; set; }
    public int Id { get { return _id; } }

    public string ProjName
    {
        get { return _name; }
        set { _name = value; }
    }

    private void ReadUpdates()
    {
        AvailableUpdates = new List<Update>();

        for (int i = 0; i < 10; i++)
        {
            AvailableUpdates.Add(new
                Update(i, DateTime.Now.AddDays(i)));
        }
    }
}

public class Update
{
    private string _title;
    private int _uid;
    private DateTime _updatedOn;

    public Update(int id, DateTime updatedOn)
    {
        _title = $"Update:{id}";
        _uid = id;
        _updatedOn = updatedOn;
    }

    public string Title
    {
        get { return _title; }
        set { _title = value; }
    }

    public int UId
    {
        get { return _uid; }
        set { _uid = value; }
    }

    public DateTime UpdatedOn
    {
        get { return _updatedOn; }
        set { _updatedOn = value; }
    }
}

public partial class Form1 : Form
{
    private Update _currentUpdate;
    private Project _project;

    public Form1()
    {
        InitializeComponent();

        _project = new Project(1, "Sample Project");

        DoBindings();
    }

    private void DoBindings()
    {
        NameBox.DataBindings.Add("Text", _project, "ProjName");
        IdBox.DataBindings.Add("Text", _project, "Id");

        UpdatesCombo.DataSource = _project.AvailableUpdates;
        UpdatesCombo.DisplayMember = "UId";

        _currentUpdate = (Update)UpdatesCombo.SelectedItem;

        UpdateTitle.DataBindings.Add("Text", _currentUpdate, "Title");
        UpdateDate.DataBindings.Add("Value", _currentUpdate, "UpdatedOn");
    }

    private void UpdatesCombo_SelectionChangeCommitted(object sender, System.EventArgs e)
    {
        _currentUpdate = (Update)UpdatesCombo.SelectedItem;
    }
}

如有错误请指正

Answer 1

很简单。您只需将相关控件绑定到与组合框相同的列表数据源。

var updates = _project.AvailableUpdates;

UpdatesCombo.DataSource = updates;
UpdatesCombo.DisplayMember = "UId";

UpdateTitle.DataBindings.Add("Text", updates, "Title");
UpdateDate.DataBindings.Add("Value", updates, "UpdatedOn");

数据绑定基础结构创建 CurrencyManager class per each unique list data source. The non list controls are actually bound to the Current 属性，由组合框选择更新。

windows 表单组合框中的复杂数据绑定

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