主题：[求助]帮忙看看这个问题

下面的代码看看有什么问题没有？我操作后没有任何效果，但是我加上msg看看结果时，奇迹发生了，我点完MSG的确定后，该得到的信息就有了，不知道什么原因，去掉MSG，就不行了

Valuechanged：事件

Dim sxr As WinForm.ComboBox = e.Form.Controls("ComboBox2")
Dim cj As WinForm.ComboBox = e.Form.Controls("ComboBox1")
Dim ly As WinForm.TextBox = e.Form.Controls("TextBox2")
Dim cmd As New SQLCommand
Dim dt As DataTable
Dim dr As String = e.Form.Controls("ComboBox3").value
cmd.C
cmd.CommandText = "SELECT * From kehu Where mingcheng = '" & dr & "'"

MessageBox.Show(dr)
dt = cmd.ExecuteReader
If dt.DataRows.Count > 0 Then
    cj.Text = dt.DataRows(0)("jigou")
    ly.Text = dt.DataRows(0)("laiyuanjigou")
    sxr.Text = dt.DataRows(0)("sxren")
Else
    cj.Text = Nothing
    ly.Text = Nothing
    sxr.Text = Nothing
End If