C＃：如何從LINQ查詢設置組合框valuemember

Question

行，所以我有組合框衛生組織的數據源所遇到的問題IM LINQ查詢

//load QA names 
      var qaNames = 
       from a in db.LUT_Employees 
       where a.position == "Supervisor" && a.department == "Quality Assurance" 
       select new { a, Names = a.lastName + ", " + a.firstName }; 

      cboQASupervisor.DataSource = qaNames; 
      cboQASupervisor.DisplayMember = "Names"; 

的結果是，當我嘗試添加的代碼

下一行

cboQASupervisor.ValueMember = "ID"; 

我得到運行時它不能投的匿名類型的錯誤。我該如何解決這個問題？

校正： 錯誤是：

無法綁定到新值構件。 參數名：價值

Answer 1

您指定ID作爲值字段，但你沒有ID屬性在你的匿名類型。
假設你在LUT_Employees有ID對象：

var qaNames = (
    from a in db.LUT_Employees 
    where a.position == "Supervisor" && a.department == "Quality Assurance" 
    select new { a.ID, Names = a.lastName + ", " + a.firstName }) 
    .ToList(); 

cboQASupervisor.DataSource = qaNames; 
cboQASupervisor.DisplayMember = "Names"; 
cboQASupervisor.ValueMember = "ID"; 

Answer 2

你可以試試這個：

 var qaNames = 
     from a in db.LUT_Employees 
     where a.position == "Supervisor" && a.department == "Quality Assurance" 
     select new { Id = a.ID, Names = a.lastName + ", " + a.firstName }; 

     cboQASupervisor.DataSource = qaNames.ToList(); 
     cboQASupervisor.DisplayMember = "Names"; 
     cboQASupervisor.ValueMember = "Id"; 

添加.ToList()到你的代碼中的數據源行。