無法檢索頁面加載的dropdownlist.selectedvalue？

Question

我有一個下拉框，它的價值是由datasqlsource檢索，但是我想在頁面加載計數值，但它似乎是，如果你使用cmd.ExcuteScalar沒有指望

'Dim adapter As New SqlDataAdapter 
    'Dim ds As New DataSet 


    'Dim connectionString = ConfigurationManager.ConnectionStrings("myProject").ConnectionString 
    'Dim myConn As New SqlConnection(connectionString) 

    'Dim cmd = "SELECT * FROM Group Where groupID='" & DropDownList1.SelectedValue & "' AND customerID='" & Session("customerID") & "'" 






    'Try 
    ' myConn5.Open() 
    ' Dim myCmd5 As New SqlCommand(cmd5, myConn5) 
    ' adapter.SelectCommand = myCmd5 
    ' adapter.Fill(ds, "Group") 
    ' ' txtQuan.Text = adapter.SelectCommand.ExecuteScalar().ToString() 
    ' adapter.Dispose() 
    ' myCmd5.Dispose() 
    ' ' txtQuan.Text = ds.Tables(0).Rows.Count 
    ' If ds.Tables(0).Rows.Count >= 10 Then 
    '  lblNoPpl.Text = "The group is full" 
    ' Else 
    '  Dim numLefts As Integer = 10 - ds.Tables(0).Rows.Count 
    '  lblNoPpl.Text = numLefts.ToString() + "space left" 



    'Catch ex As Exception 
    ' MsgBox("Can not open connection ! ") 
    'End Try 

Answer 1

（）方法來檢索計數，則SQL應

選擇COUNT（*）FROM羣裏組ID = ' 「& DropDownList1.SelectedValue &」' AND的customerID =' 「&會議（ 」的customerID「）&」 '「