数据绑定一个ArrayList VB.NET中一个ListBox？ [英] Databinding an ArrayList to a ListBox in VB.NET?

问题描述

我在VB.NET工作

我有填充类发票的对象一个ArrayList名为发票。

I have an ArrayList named Invoices populated with objects of the class Invoice.

我想将数据绑定这一个列表框，这样为ArrayList的内容更新，改变了列表框更新。我实现了对发票类的ToString功能，我只是不知道我怎么会去了解的ArrayList绑定到ListBox。

I'd like to data bind this to a ListBox so that as the contents of the ArrayList are updated and changed the ListBox updates. I've implemented a .ToString function on the Invoice class, I just don't know how I'd go about binding the ArrayList to the ListBox.

有什么建议？

推荐答案

我要作一个假设，这是的WinForms。

I'm going to make the assumption that this is winforms.

如果你想双向数据绑定，你需要几件事情：

If you want two-way data-binding, you need a few things:

• 来检测添加/删除等，你需要一个数据源，实现 IBindingList的;上课，的BindingList＆LT; T＆GT; 是显而易见的选择（的ArrayList 根本不会做......）


• 要检测更改为性质的对象，您需要执行 INotifyPropertyChanged的（通常你可以使用*更改的格局，但这不是由德高望重的的BindingList＆LT; T＆GT; ）

• to detect addition/removal etc, you need a data-source that implements IBindingList; for classes, BindingList<T> is the obvious choice (ArrayList simply won't do...)
• to detect changes to properties of the objects, you need to implement INotifyPropertyChanged (normally you can use the "*Changed" pattern, but this isn't respected by BindingList<T>)

幸运的是，的ListBox 处理这两种。一个完整的示例如下：我使用C＃，但其概念是一样的...

Fortunately, ListBox handles both of these. A full example follows; I've used C#, but the concepts are identical...

using System;
using System.ComponentModel;
using System.Windows.Forms;
class Data : INotifyPropertyChanged{
    private string name;
    public string Name
    {
        get { return name; }
        set { name = value; OnPropertyChanged("Name"); }
    }
    public event PropertyChangedEventHandler PropertyChanged;
    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null) handler(this,
            new PropertyChangedEventArgs(propertyName));
    }
}
static class Program
{
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Button btn1, btn2;
        BindingList<Data> list = new BindingList<Data> {
            new Data { Name = "Fred"},
            new Data { Name = "Barney"},
        };
        using (Form frm = new Form
        {
            Controls =
            {
                new ListBox { DataSource = list, DisplayMember = "Name",
                     Dock = DockStyle.Fill},
                (btn1 = new Button { Text = "add", Dock = DockStyle.Bottom}),
                (btn2 = new Button { Text = "edit", Dock = DockStyle.Bottom}),
            }
        })
        {
            btn1.Click += delegate { list.Add(new Data { Name = "Betty" }); };
            btn2.Click += delegate { list[0].Name = "Wilma"; };
            Application.Run(frm);
        }
    }
}

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