If showmx Is Nothing Then
Dim trls As object = pptable.GetElementsByTagName("tr")
For i As Integer = 1 To trls.count - 3
MXRow = new List(of String)
For Each td As object In trls(i).GetElementsByTagName("span")
MXRow.Add(td.Innertext) ’这里用msgbox测试都正常
Next
MXTab.Add(MXRow) ’把行的集合添加到 MXTab
Next