WorkItem validation of "Plain Text" fields

I've got an application that bridges our help desk system with TFS (one way from Help Desk to TFS). When I create the work item in TFS, in some situations I'm getting an "InvalidCharacters" validation error.

The field I'm using is the standard "Description" field, which is defined as "Plain Text" in t开发者_开发百科he Work Item definition.

This is only happening on one record, so I'm sure it's the data, but I can't figure out what character is being considered to be invalid. Is there any guidance on what will trigger the InvalidCharacters validation on "Plain Text" fields?

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It looks like this field is unable to display the extended ASCII characters. There was an a with an accent grave (à) in the string I was trying to save.

-- EDIT --

This actually became even more frustrating. The character representation when I did a ToCharArray() was "à", however, when I finally found the spot in the string where it was bombing, the actual character was a single-character ellipses (...). Which was probably caused by someone copying and pasting from Word into our help-desk system for comments.

My ultimate resolution was a brute force spin through the char array, replacing any character that had an int value of greater than 127 with something else (in my case, a question mark).

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A ‘string’ field is invalid if it contains control characters other than newline, carriage return, and tab or if it contains mismatched surrogate characters. Longtext fields (like plaintext) accept everything except mismatched surrogate pairs. Make sure your copy/paste is resulting in Unicode being pasted in.

You can use a Regex function to compress all white space down to a " " character, such as this:

Regex.Replace( text, @"\s+", " " ); 

Although that actually strips more than you technically need to, since it takes out newline, carriage return and tab too.

Hope this helps!