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How to carriage return C# string without \r\n?

This is my problem.
A user can enter text into a text area in the browser. Which is then emailed out to users.
What I want to know is that how do I handle carriage return? If I enter \r\n for carriage return, the email (which is a plain text email) has actual \r\n in it.
In other words:
On the SQL server end
Case 1:
if I do this before the email gets sent
(notice the line break after line 1)
update emails
set
body='line 1
line 2'
where
id=100
the email goes out correctly
Case 2:
update emails
set
body='line 1'+char(13) + char(10) +'line 2'
where
id=100
This email also goes out correctly
Case 3:
However if I do this
update emails
set
body='line 1 \r\n line 2',
where
id=100
the email would have the actual text \r\n in it.
How do I simulate case 1/2 through c# ?

SQL literals (at least those in SQL Server) do not support such escape sequences (although you can just hit enter within the string literal so that it spans multiple lines). See this answer for some alternatives if writing it as an SQL string is a requirement.
If running the SQL programmatically from C#, use parameters which will handle this just fine:
sqlCommand.CommandText = "update emails set body=#body where id=#id"
sqlCommand.Parameters.AddWithValue("#body", "line 1 \r\n line2");
Note that the handling of the string literal (and conversion of the \r and \n character escape sequences) happens in C# and the value (with CR and LF characters) is passed to SQL.
If the above didn't address the problem, keep reading.
4.10.13 The textarea element:
For historical reasons, the element's value is normalised in three different ways for three different purposes. The raw value is the value as it was originally set. It is not normalized. The API value is the value used in the value IDL attribute. It is normalized so that line breaks use "LF" (U+000A) characters. Finally, there is the form submission value. [Upon form submission the textarea] is normalized so that line breaks use U+000D CARRIAGE RETURN U+000A LINE FEED (CRLF) character pairs, and in addition, if necessary given the element's wrap attribute, additional line breaks are inserted to wrap the text at the given width.
Note that CR and LF represent characters and not the two-character sequence of \ followed by either the r or n characters - this form is often found in string literals. If it appears as such then something is doing the incorrect conversion and putting (or leaving) the \ there. Or, perhaps there is some misguided "add slashes" hack somewhere?
As pointed out, while URL decode is likely wrong, it won't directly do this conversion. However, if the conversion happened previously before being "URL Encoded", then it will (correctly) decode to (incorrect) values.
In either case, it's a bug. So find out where the incorrect data conversion is introduced and fix it (attach a debugger and/or monitor the network traffic for clues) - the required information to isolate where is simply not present in the post.

Use whatever c#'s string replace method is to replace "\\r\\n" with "\r\n" and that should fix it.

Trim or remove characters of type (0x0000)

I have written a C# application that is extracting all of the text that is contained in the pdf and store it in a database.
The problem I have is when reusing the stored information and displaying it on my website with XML. I get an error that states something like invalid character 0x0000, and from what I have read, the 0x0000 character isn't allowed in XML.
So, my question is; Does anyone know how I can remove all characters of type 0x0000 with C# before I store it in my database?

How about using Replace
Returns a new string in which all occurrences of a specified Unicode
character or String in the current string are replaced with another
specified Unicode character or String.
string s = "a\0b";
string r = s.Replace('\0',' ');

How to read double quotes (") in a text file in C#?

I have to read a text file and then to parse it, in C# using VS 2010. The sample text is as follows,
[TOOL_TYPE]
; provides the name of the selected tool for programming
“Phoenix Select Advanced”;
[TOOL_SERIAL_NUMBER]
; provides the serial number for the tool
7654321;
[PRESSURE_CORRECTION]
; provides the Pressure correction information requirement
“Yes”;
[SURFACE_MOUNT]
; provides the surface mount information
“Yes”;
[SAPPHIRE_TYPE]
; provides the sapphire type information
“No”;
Now I have to parse only the string data (in double quotes) and headers (in square brackets[]), and then save it into another text file. I can successfully parse the headers but the string data in double quotes is not appearing correctly, as shown below.
[TOOL_TYPE]
�Phoenix Select Advanced�;
[TOOL_SERIAL_NUMBER]
7654321;
[PRESSURE_CORRECTION]
�Yes�;
[SURFACE_MOUNT]
�Yes�;
[SAPPHIRE_TYPE]
�No�;
[EXTENDED_TELEMETRY]
�Yes�;
[OVERRIDE_SENSE_RESISTOR]
�No�;
Please note a special character (�) which is appearing every time whenever a double quotes appear.
How can I write the double quotes(") in the destination file and avoid (�) ?
Update
I am using the following line for my parsing
temporaryconfigFileWriter.WriteLine(configFileLine, false, Encoding.Unicode);
Here is the complete code I am using:
string temporaryConfigurationFileName = System.Environment.GetFolderPath(Environment.SpecialFolder.Desktop) + "\\Temporary_Configuration_File.txt";
//Pointers to read from Configuration File 'configFileReader' and to write to Temporary Configuration File 'temporaryconfigFileWriter'
StreamReader configFileReader = new StreamReader(CommandLineVariables.ConfigurationFileName);
StreamWriter temporaryconfigFileWriter = new StreamWriter(temporaryConfigurationFileName);
//Check whether the 'END_OF_FILE' header is specified or not, to avoid searching for end of file indefinitely
if ((File.ReadAllText(CommandLineVariables.ConfigurationFileName)).Contains("[END_OF_FILE]"))
{
//Read the file untill reaches the 'END_OF_FILE'
while (!((configFileLine = configFileReader.ReadLine()).Contains("[END_OF_FILE]")))
{
configFileLine = configFileLine.Trim();
if (!(configFileLine.StartsWith(";")) && !(string.IsNullOrEmpty(configFileLine)))
{
temporaryconfigFileWriter.WriteLine(configFileLine, false, Encoding.UTF8);
}
}
// to write the last header [END_OF_FILE]
temporaryconfigFileWriter.WriteLine(configFileLine);
configFileReader.Close();
temporaryconfigFileWriter.Close();
}

Your input file doesn't contain double quotes, that's a lie. It contains the opening double quote and the closing double quote not the standard version.
First you must ensure that you are reading your input with the correct encoding (Try multiple ones and just display the string in a textbox in C# you'll see if it show the characters correctly pretty fast)
If you want such characters to appear in your output you must write the output file as something else than ASCII and if you write it as UTF-8 for example you should ensure that it start with the Byte Order Mark (Otherwise it will be readable but some software like notepad will display 2 characters as it won't detect that the file isn't ASCII).
Another choice is to simply replace “ and ” with "

It appears that you are using proper typographic quotes (“...”) instead of the straight ASCII ones ("..."). My guess would be that you read the text file with the wrong encoding.
If you can see them properly in Notepad and neither ASCII nor one of the Unicode encodings works, then it's probably codepage 1252. You can get that encoding via
Encoding.GetEncoding(1252)

How to read/write text and avoid special character signs (<, , >, etc)

I am currently parsing some C# scripts that are stored in a database, extracting the body of some methods in the code, and then writing an XML file that shows the id, the body of the extracted methods, etc.
The problem I have write now is that when I write the code in the XML I have to write it as a literal string, so I thought I'd need to add " at the beginning and end:
new XElement("MethodName", #"""" + Extractor.GetMethodBody(rule.RuleScript, "MethodName") + #"""")
This works, but I have a problem, things that are written in the DB as
for (int n = 1; n < 10; n++)
are written into the XML file (or printed to console) as:
for (int n = 1; n < 10; n++)
How can I get it to print the actual character and not its code? The code in the database is written with the actual charaters, not the "safe" < like one.

Inside xml (as a text value) it is correct for < to be encoded as <. The internal representation of xml doesn't affect the value, so let it get encoded. You can get around this by forcing a CDATA section, but in all honesty - it isn't worth it. But here is an example using CDATA:
string noEncoding = new XElement("foo", new XCData("a < b")).ToString();

Why do you think that you have to write it as a literal string? That is not so. Besides, you are not writing it as a literal string at all, it's still a dynamic string value only that you have added quotation marks around it.
A literal string is a string that is written litteraly in the code, like "Hello world". If you get the string in any other way, it's not a literal string.
The quotation marks that you have added to the string simply adds quotation marks to the value, they don't do anything else to the string. You can add the string with the quotation marks just fine:
new XElement("MethodName", Extractor.GetMethodBody(rule.RuleScript, "MethodName"))
Now, the characters that are encoded when they are put in the XML, is because they need to be encoded. You can't put a < character inside a value without encoding it.
If you show the XML, you will see the encoded values, and that is just a sign that it works as it should. When you read the XML, the encoded characters will be decoded, and you end up with the original string.

I don't know what software he's going to use to read the XML, but any that I know of will throw an error on parsing any XML that does not escape < and > chars which aren't used as tag starts and ends. It's just part of the XML specification; these chars are reserved as part of the structure.
If I were you, then, I'd part ways with the System.XML utilities and write this file yourself. Any decent XML tool is going to encode those chars for you, so you should probably not use them. Go with a StreamWriter and create the output the way you are being told to. That way you can control the XML output yourself, even if it means breaking the XML specification.
using (StreamWriter sw = new StreamWriter("c:\\xmlText.xml", false, Encoding.UTF8))
{
sw.WriteLine("<?xml version=\"1.0\"?>");
sw.WriteLine("<Class>");
sw.Write("\t<Method Name=\"MethodName\">");
sw.Write(#"""" + Extractor.GetMethodBody(rule.RuleScript, "MethodName") + #"""");
sw.WriteLine("</Method>");
// ... and so on and so forth
sw.WriteLine("</Class>");
}

C# Special Characters not displayed propely in XML

i have a string that contains special character like (trademark sign etc). This string is set as an XML node value. But the special character is not rendered properly in XML, shows ??. This is how im using it.
String str=xxxx; //special character string
XmlNode node = new XmlNode();
node.InnerText = xxxx;
I tried HttpUtility.htmlEncode(xxxx) but it converts it into "&amp ;#8482;" so the output of xml is "&#8482"; instead of ™
I have also tried XmlConvert.ToString() and XmlConvert.EncodeName but it gives ??

I strongly suspect that the problem is how you're viewing the XML. Have you made sure that whatever you're viewing it in is using the right encoding?
If you save the XML and then reload it and fetch the inner text as a string, does it have the right value? If so, where's the problem?
You shouldn't perform extra encoding yourself - let the XML APIs do their job.

I've had issues with some characters using htmlEncode() before, as well. Here's a good example of different ways to write your XML: Different Ways to Escape an XML String in C#. Check out #3 (System.Security.SecurityElement.Escape()) and #4 (System.Xml.XmlTextWriter), these are the methods I typically use.