在页面加载事件中填充下拉列表

Question

我看不出为什么这不起作用。

我有一个名为ddlRoomName的下拉列表和一个名为roomlist的SQL表。

当我在SQL编辑器中运行SQL命令它工作正常。但是，当我加载页面的房间不加载！

我在这里错过了一些明显的东西吗？

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

您只是在回发中加载它们。它真的是你想要的吗？也许你想：

If Not Page.IsPostBack Then 

End If 

（当时ViewState将保持在回传的DropDownList项目）