如何检查任务<list <usermethod>＆gt;是空的

Question

App.Database.query(UserName.Text, Password.Text)返回listAsync但即使没有用户显示YES !!

private async void Button_Clicked_1(object sender, EventArgs e)
{
    if(App.Database.query(txtUserName.Text, txtPassword.Text) == null )
    {
        await DisplayAlert("Alert", " No user", "OK");
    }
    else
    {
        await DisplayAlert("Alert", "Yes user", "OK");
    }
}

Answer 1

如果返回Task<IList<T>>和async，则需要等待它并检查空列表。

...
var users = await App.Database.query(txtUserName.Text, txtPassword.Text);
if(!users.Any())
...