在頁面加載事件中填充下拉列表

Question

我看不出爲什麼這不起作用。

我有一個名爲ddlRoomName的下拉列表和一個名爲roomlist的SQL表。

當我在SQL編輯器中運行SQL命令它工作正常。但是，當我加載頁面的房間不加載！

我在這裏錯過了一些明顯的東西嗎？

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 
    If Page.IsPostBack Then 

     ddlRoomName.Items.Clear() 
     ddlRoomName.Items.Add(New ListItem("--Select Room--", "")) 
     ddlRoomName.AppendDataBoundItems = True 

     Dim strConnString As String = ConfigurationManager.ConnectionStrings("a_cisco").ConnectionString 
     Dim strQuery As String = "Select * from roomlist" 
     Dim con As New SqlConnection(strConnString) 
     Dim cmd As New SqlCommand() 

     cmd.CommandType = CommandType.Text 
     cmd.CommandText = strQuery 
     cmd.Connection = con 

     Try 
      con.Open() 
      ddlRoomName.DataSource = cmd.ExecuteReader() 
      ddlRoomName.DataTextField = "RoomName" 
      ddlRoomName.DataValueField = "intRoom" 
      ddlRoomName.DataBind() 

     Catch ex As Exception 
      Throw ex 
     Finally 
      con.Close() 

     End Try 
    End If 
End Sub 

Answer 1

您只是在回發中加載它們。它真的是你想要的嗎？也許你想：

If Not Page.IsPostBack Then 

End If 

（當時ViewState將保持在回傳的DropDownList項目）