主题：窗口提示错误，请问原因（已解决）

Dim cmd As New SQLCommand
Dim dt As DataTable
Dim cmb As WinForm.ComboBox = e.Form.Controls("用户名")
cmd.ConnectionName = "User" ’原帮助这里指定数据源
cmd.CommandText = "SELECT DISTINCT Name From {用户}"
dt = cmd.ExecuteReader()
For Each dr As DataRow In dt.Datarows
    cmb.Items.Add(dr("用户名"))
Next

if .Items.Count > 0 Then ‘原帮助这里多了一个判断
    cmb.SelectedIndex = 0

end if