DataColChanged
If e.DataCol.Name = "记录时间" AndAlso e.DataRow.IsNull(e.DataCol) = False Then
Dim dr As DataRow = e.DataTable.Find("_Identify < " & e.DataRow("_Identify"),"_Identify Desc",0)
If dr IsNot Nothing Then
Dim tp As TimeSpan = e.DataRow("记录时间") - dr("记录时间")
e.DataRow("天数") = tp.TotalDays
Else
e.DataRow("天数") = 0
End If
End If