ASP链接sql输入数据库账号密码错误如何显示对话框提示

Dim error, errMsg

error = false

On Error Resume Next

Set dbconn = GetSQLServerConnection(...)

If Err Then

	error = True

    errMsg = Err.Description

    Err.Clear

End If

On Error Goto 0

Private Sub cmdEnter_Click()

On Error GoTo cnnerror

If Trim$(txtUsername.Text) = "" Then
   MsgBox "请输入数据库用户名！", vbOKOnly + vbExclamation, "图书租借管理系统"
   txtUsername.SetFocus
   Exit Sub
End If

If Trim$(txtServerName.Text) = "" Then
   MsgBox "请输入服务器名称！", vbOKOnly + vbExclamation, "图书租借管理系统"
   txtServerName.SetFocus
   Exit Sub
End If

strConnection = "Provider=sqloledb;" & "Data Source=" & Trim$(txtServerName.Text) & _
         ";" & "Initial Catalog=" & Trim$(txtDatabaseName.Text) & ";" & "User Id=" & _
          Trim$(txtUsername.Text) & ";" & "Password=" & Trim$(txtPassword.Text) & ";"
cnnConnection.CursorLocation = adUseClient
cnnConnection.Open strConnection

strDataSource = Trim$(txtServerName.Text)
strInitialCatalog = Trim$(txtDatabaseName.Text)
strUserId = Trim$(txtUsername.Text)
strPassword = Trim$(txtPassword.Text)

frmLogin.Show
Unload Me
Exit Sub

cnnerror:
   MsgBox Err.Description
End Sub