主题：连接SQsever登录问题(测试）

你确定按钮当然要出错，应为你屏蔽了这行代码：

Dim UserName As String = e.Form.Controls("UserName").Value
Dim cmd As New SQLCommand
Dim dt As DataTable
Dim dr As DataRow
'cmd.Connection Name = "test2"   外部数据源
If UserName = ""  Then
    Messagebox.show("请选择用户!","提示",MessageBoxButtons.OK,MessageBoxIcon.Information)
    Return
End If