需要手动将可观察集合填充到列表视图或任何可以显示数据的元素中

Question

正如问题所说，我被困在用我的内容填充数据容器（listview）上，希望有人能告诉我一个亮点！

这是我拥有的类（我的搜索框发送一个我想在数据库上找到的参数名称，对我的数据库的查询填充并检索一个 ObservableCollection，其中填充了尽可能多的参数，然后我想把它展示到我的列表视图，希望有人可以帮助我！提前感谢！

public class LobbyUserViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }
    private DbOperations.DbOperations db;
    private ObservableCollection<Person> persons;
    public LobbyUserViewModel()
    {
        persons = new ObservableCollection<Person>();
        db = new DbOperations.DbOperations();
        searchPersonCommand = new RelayCommand(SearchPerson, CanSearchPerson);            
    }
    public ICommand SearchPersonCommand
    {
        get { return searchPersonCommand; }
    }
    public bool CanSearchPerson(object obj)
    {
        if (SearchPersonBox != string.Empty)
            return true;
        return false;
    }
    public void SearchPerson(object obj)
    {
        Persons = db.DadosForSearchPerson(searchPerson);
        if (Persons != null)
        {
            foreach (var item in Persons)
            {
                MessageBox.Show(item.Name + " - " + item.Email);
                // This works, but I need these 2 items added on a listview
            }
        }
        else
        {
            MessageBox.Show("Noone found with that name");
        }
    }
    public string SearchPersonBox
    {
        get { return searchPerson.Name; }
        set
        {
            searchPerson.Name = value;
            OnPropertyChanged("SearchPerson");
        }
    }
    public ObservableCollection<Person> Persons
    {
        get { return persons; }
        set { persons = value; }
    }

Answer 1

你需要在你的Persons二传手中提高属性更改。目前，每次调用SearchPerson()时都会替换ObservableCollection，但由于您不提高PropertyChanged，WPF无法知道它已更改。

由于每次都替换集合，因此仅改用List<T>可能会更有效。 仅当您要动态添加/删除/移动现有集合中的项目时，才需要ObservableCollection<T>。

Answer 2

+1 代表 GazTheDestroyer。 没有OnPropertyChanged的解决方案是这样的：

public void SearchPerson(object obj)
{
    if(!CanSearchPerson(obj))
      return;
    Persons.Clear();
    var result = db.DadosForSearchPerson(searchPerson);
    if (result != null)
    {
        foreach (var item in result )
        {
            MessageBox.Show(item.Name + " - " + item.Email);
            // This works, but I need these 2 items added on a listview
            Persons.Add(item)
        }
    }
    else
    {
        MessageBox.Show("Noone found with that name");
    }
}

你的 Xaml

<ListView ItemsSource="{Binding Persons}">
 <ListView.View>
  <GridView>
   <GridViewColumn Width="140" Header="Name" DisplayMemberBinding="{Binding Name}"  />
   <GridViewColumn Width="140" Header="Email" DisplayMemberBinding="{Binding Email}" />
   </GridView>
  </ListView.View>
 </ListView>