具有linq和多项选择的列表框

Question

有2个列表框：患者和会话。 根据第一个选择中的多项选择，需要在第二个中显示过滤后的信息（使用linq查询）。

带注释的字符串有效，但只允许在第一个列表框中选择一个项目。

我绝对知道它成功收集了Patients to List变量，但是当我使用Contains时，第二个列表框为空。

private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
    DataClasses1DataContext dbContext = new DataClasses1DataContext();
    List<string> selectedItems = (from object o in listBox1.SelectedItems select listBox1.GetItemText(o)).ToList();
    listBox2.DataSource = dbContext.Sessions
    //.Where(pID => pID.PatientID == listBox1.GetItemText(listBox1.SelectedValue))
      .Where(pID => selectedItems.Contains(pID.PatientID));
    listBox2.DisplayMember = "Start";
    listBox2.ValueMember = "SessionID";
}

会话和dbContext类的定义：

public partial class Session : INotifyPropertyChanging, INotifyPropertyChanged
    {
    ...
    public int SessionID
        {
        ...
        }
    public string PatientID
        {
        ...
        }
    }

public partial class DataClasses1DataContext : System.Data.Linq.DataContext
    {
    ...
    public System.Data.Linq.Table<Session> Sessions
        {
        ...
        }
    }

Answer 1

我不知道您的listbox1中具有哪种类型的元素。 我假设类型名为Session ：

    private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        DataClasses1DataContext dbContext = new DataClasses1DataContext();
        List<string> selectedItems = (from object o in listBox1.SelectedItems select listBox1.GetItemText(o)).ToList();
        listBox2.DataSource = dbContext.Sessions
            .Where(pID => listBox1.SelectedItems.OfType<Session>().Select(x => x.PatientID).Contains(pID.PatientID));
        listBox2.DisplayMember = "Start";
        listBox2.ValueMember = "SessionID";
    }