异常：类型不匹配。

错误：类型不匹配。。
程序如下，一个定时闹钟程序，照课本敲的，但运行时错误是红色部分类型不匹配，求解。。
Option Explicit
Private Declare Function Beep Lib "kernel32" (ByVal dwFreq As Long, ByVal dwDuration As Long) As Long
Dim msTime$

Private Sub CmdOk_Click()
  Timer2.Enabled = True
  Timer1.Enabled = True
LabShow.Caption = DateDiff("s", Format$(DT1.Value, "hh:mm:ss"), msTime$) Open (App.Path & "\Set.ini") For Output As #1
  Print #1, DT1.Value
  Close #1
End Sub

Private Sub Command2_Click()
  Timer3.Enabled = False
  Timer2.Enabled = False
  Timer1.Enabled = False
  Unload Me
End Sub

Private Sub Form_Load()
  Dim Intext$
  On Error GoTo ToExit
  Open (App.Path & "\Set.ini") For Input As #1
  Line Input #1, Intext
  DT1.Value = Intext
  Close #1
  Exit Sub
ToExit:
  Resume Next
End Sub

Private Sub Timer1_Timer()
  TxtNow.Text = Time
End Sub

Private Sub Timer2_Timer()
  On Error Resume Next
  msTime$ = Format$(DT1.Value, "hh:mm:ss")
  If msTime$ = "0:0:0" Then
  LabShow.Caption = vbNullString
  Else
  If DateDiff("s", Format$(TxtNow.Text, "hh:mm:ss"), msTime$) >= 0 Then
  LabShow.Caption = DateDiff("s", Format$(TxtNow.Text, "hh:mm:ss"), msTime$)
  Else
  LabShow.Caption = vbNullString
  End If
  End If
  If LabShow.Caption = "0" Then
  LabShow.Caption = "时间到"
  Timer3.Enabled = True
  Timer2.Enabled = False
  End If
   
End Sub

Private Sub Timer3_Timer()
  Dim Musics As Long
  Musics = CLng(600)
  Beep Musics, 500
  
End Sub

[解决办法]
日期型，而不是字符串类型。改成：

VB code

DateDiff("s", CData(Format$(DT1.Value, "hh:mm:ss")), CDate(msTime$))