C# LongListSelector.SelectedItem可以';不要强制转换到我的对象类
我有一个LongListSelector,其中包含来自SQLite数据库的对象:C# LongListSelector.SelectedItem可以';不要强制转换到我的对象类,c#,sqlite,windows-phone-8,windows-phone,longlistselector,C#,Sqlite,Windows Phone 8,Windows Phone,Longlistselector,我有一个LongListSelector,其中包含来自SQLite数据库的对象: protected override async void OnNavigatedTo(NavigationEventArgs e) { SQLiteAsyncConnection conn = new SQLiteAsyncConnection(DB_PATH); var query = conn.Table<Prasanja>().Where(x => x.id == 3); v
protected override async void OnNavigatedTo(NavigationEventArgs e)
{
SQLiteAsyncConnection conn = new SQLiteAsyncConnection(DB_PATH);
var query = conn.Table<Prasanja>().Where(x => x.id == 3);
var result = await query.ToListAsync();
foreach (var item in result)
{
var query1 = conn.Table<Odgovori>()
.Where(y => y.Prasanja_id == item.id);
txtPrasanje.Text = item.Tekst;
var resultOdgovori = await query1.ToListAsync();
foreach (var itemOdgovor in resultOdgovori)
{
Lista.Add(itemOdgovor.Odgovor.ToString());
lstOdgovori.ItemsSource = Lista;
}
}
这里的问题是,在执行此代码后,来自Odgovori类的对象odg返回null。如何修复此问题?您正在将
字符串添加到Lista
中,这就是您的角色设置不起作用的原因。如果您在Odgovori
类中重写了ToString()
方法,我相信只要将Odgovori
对象添加到Lista
private void lstOdgovori_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
LongListSelector selector = sender as LongListSelector;
if (selector == null)
return;
Odgovori odg = selector.SelectedItem as Odgovori;
if (odg == null)
return;
if(odg.Tocno==null)
MessageBox.Show("Try again");
else MessageBox.Show("True!!!");
}