它应该是这样的(未经测试!)
Dim date1 As DateTime = DateTime.ParseExact(yourdate1.ToString(), "yyyyMMdd", CultureInfo.InvariantCulture)
Dim date2 As DateTime = DateTime.ParseExact(yourdate2.ToString(), "yyyyMMdd", CultureInfo.InvariantCulture)
Dim days As Integer = date1.Subtract(date2).Days
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