将列表绑定到DataSource

Question

我希望能够将列表绑定到列表框数据源,并且当列表被修改时,列表框的UI会自动更新.(Winforms不是ASP).这是一个示例:

private List<Foo> fooList = new List<Foo>();

    private void Form1_Load(object sender, EventArgs e)
    {
        //Add first Foo in fooList
        Foo foo1 = new Foo("bar1");
        fooList.Add(foo1);

        //Bind fooList to the listBox
        listBox1.DataSource = fooList;
        //I can see bar1 in the listbox as expected
    }

    private void button1_Click(object sender, EventArgs e)
    {
        //Add anthoter Foo in fooList
        Foo foo2 = new Foo("bar2");
        fooList.Add(foo2);
        //I expect the listBox UI to be updated thanks to INotifyPropertyChanged, but it's not
    }

class Foo : INotifyPropertyChanged
{
    private string bar_ ;
    public string Bar
    {
        get { return bar_; }
        set 
        { 
            bar_ = value;
            NotifyPropertyChanged("Bar");
        }
    }

    public Foo(string bar)
    {
        this.Bar = bar;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    private void NotifyPropertyChanged(string info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }

    public override string ToString()
    {
        return bar_;
    }
}

如果我更换List<Foo> fooList = new List<Foo>();的BindingList<Foo> fooList = new BindingList<Foo>();,然后它工作.但我不想改变原来的傻瓜类型.我希望这样的工作:listBox1.DataSource = new BindingList<Foo>(fooList);

编辑:我也在这里阅读List <T> vs BindingList <T>来自Ilia Jerebtsov的优点/ DisAdvantages:"当你将BindingSource的DataSource设置为List <>时,它会在内部创建一个BindingList来包装你的列表".我认为我的示例只是证明了这不是真的:我的List <>似乎没有内部包装到BindingList <>中.

Answer 1

您的示例中没有BindingSource.

你需要像这样修改它来使用BindingSource

   var bs = new BindingSource();
   Foo foo1 = new Foo("bar1");
   fooList.Add(foo1);

     bs.DataSource = fooList; //<-- point of interrest

    //Bind fooList to the listBox
    listBox1.DataSource = bs; //<-- notes it takes the entire bindingSource

编辑

请注意(正如评论中指出的那样) - bindingsource不起作用 INotifyPropertyChanged

Answer 2

尝试

listBox1.DataSource = new BindingList<Foo>(fooList);

然后

private void button1_Click(object sender, EventArgs e)
{
    Foo foo2 = new Foo("bar2");
    (listBox1.DataSource as BindingList<Foo>).Add(foo2);
}

这将更新fooList而无需更改其原始类型.此外,当您更改Bar成员时,它将更新ListBoxfooList[1].Bar = "Hello";

但是,您必须DisplayMember将ListBox 的属性设置为"Bar",或者保持.ToString()覆盖Foo类定义中的内容.

为了避免每次都要进行强制转换,我建议你使用与List定义相同级别的BindingList变量:

private List<Foo> fooList;
private BindingList<Foo> fooListUI;

fooListUI = new BindingList<Foo>(fooList);
listBox1.DataSource = fooListUI;

并在按钮中:

Foo foo2 = new Foo("bar2");
fooListUI.Add(foo2);