无法投类型的对象（LINQ到对象）

Question

Function searchByName(lName As String) As List(Of Employees) 

     Dim employees As New Employees 
     Dim employeeList As New List(Of Employees) 
     Dim resultList As New List(Of Employees) 
     employeeList = employees.getEmployeeObject 

     resultList = From employeesObj In employeeList 
        Where employeesObj.LastName = lName 
        Select employeesObj.EmployeeID 
     Return resultList 
    End Function 

Answer 1

的最LINQ的方法，这也适用于建在这里使用的理解语法，是IEnumerable(Of T)而不是List(Of T)结果。为了返回表达式的结果，您需要将结果放入列表中，最常用的方法是对结果IEnumerable(Of Employees)引用调用ToList扩展方法。

例：

resultList = From employeesObj In employeeList 
      Where employeesObj.LastName = lName 
      Select employeesObj.EmployeeID 
Return resultList.ToList()