outlook高级查找

a673575727

AdvancedSearch请问一下这个属于异步查找的么？
因为我同一个查找有时候能找到有时候却找不到，如果是异步的请问一下有什么判断语句能判断他查找结束了呢？
Dim mail_sch As Search
    Dim strF As String
    Dim strS As String
    Dim strTag As String
    strS = "Inbox"      '目录
    strT = "xxxxxx" & date_tiqu
    Debug.Print strT
    strF = "urn:schemas:httpmail:subject ='" & strT & "'"
    Debug.Print strF
    strTag = "SubjectSearch"
   
    '开启outlook
    Dim OLapp As Object
    Set OLapp = CreateObject("Outlook.Application")
   
    '搜索邮件移动邮件
    Set mail_sch = OLapp.AdvancedSearch(strS, strF, False, strTag)
    'MsgBox mail_sch