简单的LINQ和List错误:WhereListIterator`1 [Task]'键入'System.Collections.Generic.List`1 [Task]'

Question

我无法理解我的错误

方法:

public List<Task> GetAllTasks()
{
    var AllTasks = from t in tasks
                   where t.Status.ToString() == "Completed" || t.Status.ToString() == "Pending"
                   select t;

    return (List<Task>)AllTasks;
}

代码背后:

protected void Page_Load(object sender, EventArgs e)
{
    TaskList tdl = (TaskList)Session["TodoList"];
    List<Task> AllTasks = tdl.GetAllTasks();
    string str = "";

    foreach (Task t in AllTasks)
    {
        str += t.ToString() + "<br />";
    }

    LblTasks.Text = str;

}

添加任务(AddTask.aspx)后,我重定向到另一个页面以显示它们,然后我得到运行时错误:

无法转换'WhereListIterator 1[Task]' to type 'System.Collections.Generic.List1 [Task]' 类型的对象.

我的LINQ有问题吗？我刚学会了嘿嘿.

谢谢.

Answer 1

您只需要.ToList()直接在查询上或返回时.如在

var AllTasks = (from t in tasks
               where t.Status.ToString() == "Completed" || t.Status.ToString() == "Pending"
               select t).ToList();

要么

return AllTasks.ToList();