DataTable internal index is corrupted

Question

I am working with a .NET WinForms app in C#, running against the 3.5 .NET framework. In this app, I am setting the .Expression member of a DataColumn in a

Answer 1

Personally, this particular bug has been my nemesis for 3 weeks in various fashions. I have solved it in one part of my code base and it shows up elsewhere (I believe I finally squashed it tonight). The exception info is rather unhelpful, and a way to force a reindex would have been a nice feature given the lack of MS to solve the problem.

I wouldn't look for MS's hotfix -- they have a KB article on it, then redirect you to an ASP.Net fix that is completely unrelated.

Ok - enough complaining. Let's see what has actually helped me in resolving this particular issue in the various places I've encountered it:

• Avoid using Default Views, and modifying the Default View if possible. Btw, .Net 2.0 has a number of reader/writer locks on creating views, so they are not the issue they were pre 2.0.
• Call AcceptChanges() where possible.
• Be careful about .Select(expression), since there is no reader/writer lock in this code -- and it is the only place (at least according to a person on the usenet so take it w/ a grain of salt -- however, this is very similar to your issue -- so using Mutexes may help)
• Set AllowDBNull to the column in question (questionable value, but reported on the usenet -- I've used it only in places where it makes sense)
• Make sure that you are not setting null (C#)/Nothing (VB) to a DataRow field. Use DBNull.Value instead of null. In your case you may wish to check that the field is not null, the expression syntax does supports the IsNull(val, alt_val) operator.

• This has probably helped me the most (absurd as it sounds): If a value is not changing, don't assign it. So in your case use this instead of your outright assignment:

  if (column.Expression != "some expression") column.Expression = "some expression";

(I removed the square brackets, not sure why they were there).

Edit (5/16/12): Just ran into this issue repeatedly (with an UltraGrid/UltraWinGrid). Used the advice of removing the sort on the DataView, and then added a sorted column which matched the DataView sort, and this resolved the issue.