通过Linq增加树节点报错

Question

请看代码

Dim tasklistdata As New lqDataContext
    Dim UserID As Integer
    UserID = (From vwUser In tasklistdata.Operators _
             Where vwUser.UserName Is Login.txtUsername.Text _
             Select vwUser.OperatorID).Single
 
    Dim lqHospitalList = From vwHospitalList In tasklistdata.SPM_Accounts _
                          Where vwHospitalList.OperatorID = UserID _
                          Order By vwHospitalList.CustomerName, vwHospitalList.Class _
                          Select vwHospitalList.CustomerName, vwHospitalList.Class, vwHospitalList.ClassCount, vwHospitalList.Charges
    tvHospitalSelect.Nodes.Add(lqHospitalList(0).CustomerName)
 
错误信息：”operator note supported”