“索引超出范围"；错误.需要检查是否填充了DataTable以避免这种情况?

问题描述

大家好，我定义了一个DataTables列表

Hi guys, i defined a list of DataTables

Dim PreSubTables As New List(Of DataTable)()

然后我解析一些源文件，并根据数据进行解析，列表PreSubTables2中的任何表都可能没有填充，因此它只是一个空列表.
稍后，当我引用列表中的第一个表时，出现索引超出范围错误"

Then I parse some source files and depending on the data, possibly none of the tables in the list PreSubTables2 is populated, so it''s just an empty list.
Later on when i refer to the first table in the list , I get "index out of range error"

 If (PreSubTables(0).Rows.Count > 0) Then ...
' just dealing with the first table:  PreSubtables(0) 
For ii = 0 To (PreSubTables(0).Rows.Count - 1)
'print the row
next
end if

在我指代``.count''的行上...

我只是想拿出一行来检查是否填充了列表中的(至少第一个)表，所以我可以将其打印出来或做其他事情.

on the line where I refer to ''.count''...

I''m just trying to come up with a line that checks whether the(at least the first)Table in the list is populated, so I can print it out or do other things. suggestions?

推荐答案

If(PreSubTables.Tables.Count > 0)
  ' this means there is some table
   If(PreSubTables.Tables(0).Rows.Count > 0)
      ' This means there is some row in table 1
      ' Do your stuff
   End If
End If

If (PreSubTables.Count > 0) Then

                       If (PreSubTables(0).Rows.Count > 0) Then

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