Newlines escaped unexpectedly in C#/ASP.NET 1.1 code

Question

Can someone explain to me why my code:

string messageBody = "abc\n" + stringFromDatabaseProcedure;

where valueFromDatabaseProcedure is not a value from the SQL database entered as

'line1\nline2'

results in the string:

"abc\nline1\\nline2"

This has resulted in me scratching my head somewhat.

I am using ASP.NET 1.1.

To clarify,

I am creating string that I need to go into the body of an email on form submit. I mention ASP.NET 1.1 as I do not get the same result using .NET 2.0 in a console app.

All I am doing is adding the strings and when I view the messageBody string I can see that it has escaped the value string.

Update What is not helping me at all is that Outlook is not showing the \n in a text email correctly (unless you reply of forward it). An online mail viewer (even the Exchange webmail) shows \n as a new line as it should.

Answer 1

ASP.NET would use <br /> to make linebreaks. \n would work with Console Applications or Windows Forms applications. Are you outputting it to a webpage?

Method #1

string value = "line1<br />line2";
string messageBody = "abc<br />" + value;

If that doesn't work, try:

string value = "line1<br>line2";
string messageBody = "abc<br>" + value;

Method #2

Use System.Environment.NewLine:

 string value = "line1"+ System.Environment.NewLine + "line2";
 string messageBody = "abc" System.Environment.NewLine + value;

One of these ways is guaranteed to work. If you're outputting a string to a Webpage (or an email, or a form submit), you'd have to use one of the ways I mentioned. The \n will never work there.

Answer 2

You need to set a watch and see where exactly your database result string gets double escaped.

Adding two strings together will never double escape strings, so its either happening before that, or after that.

Answer 3

I just did a quick test on a test NorthwindDb and put in some junk data with a \n in middle. I then queried the data back using straight up ADO.NET and what do you know, it does in fact escape the backslash for you automatically. It has nothing to do with the n it just sees the backslash and escapes it for you. In fact, I also put this into the db: foo"bar and when it came back in C# it was foo\"bar, it escaped that for me as well. My point is, it's trying to preserve the data as is on the SQL side, so it's escaping what it thinks it needs to escape. I haven't found a setting yet to turn that off, but if I do I'll let you know...

Answer 4

When I get the string out of the database, .NET escapes it automagically. However, the little @ symbol is appended to the string, which I did not notice.

So it appeared to be non-escaped to my "about to go on holiday" eye inside the ide.

Therefore when the non-escaped \n was added to the string (as the whole string is no longer escaped), it would remove the @ and show the database portion of the string escaped.

Gah, it was all an illusion.

Perhaps that holiday is overdue.

Thanks for your input.

Answer 5

If the actual string stored in the database is (spaces added for emphasis): "l i n e 1 \ n l i n e 2", then whatever stored it there probably has a bug. But assuming that is the exact string there, then the "abc\nline1\nline2" string is what happens when you look at the string which would print as "abc
line1\nline2" in a debugger which escapes it (this is a convenience, allowing you to copy-paste out of the debugger straight into code without errors).

Short answer: .NET is not escaping the string, your debugger is. The code which writes a literal "\n" into the database has a bug.