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Keep umlauts in text file with ASCII encoding

My code saves necessarily the string e.g. "Günther" with System.IO.File.WriteAllText(filePath, "Günther", Encoding.ASCII); but comes out with G?nther. I did some research but yet can't figure out how to solve this problem. It seems like there's no way because ASCII only is 7bit. But I need the text file in ASCII and with the umlaut "ü".
Is there any way to do this?

As you said: There is no umlaut in ASCII.
If it's not possible to change the File to UTF-8, the only possible way i can think of, is to replace the "ü" in the String with, e.g. "ue".

how to fix corrupt japanese character encoding

i have the following string that i know is suppose to be displayed as Japanese text
25“ú‚¨“¾‚ȃAƒ‹ƒeƒBƒƒbƒgƒRƒXƒZƒbƒg‹L”O
is there any way to decode and re-encode the text so it displays properly? i already tried using shift-jis but it did not produce a readable string.
string main = "25“ú‚¨“¾‚ȃAƒ‹ƒeƒBƒƒbƒgƒRƒXƒZƒbƒg‹L”O.zip";
byte[] mainBytes = System.Text.Encoding.GetEncoding("shift-jis").GetBytes(main);
string jpn = System.Text.Encoding.GetEncoding("shift-jis").GetString(mainBytes);
thanks!

I think that the original is Shift-JIS, but you didn't show how you did try. So here is my try to re-code it::
string s1 = "25“ú‚¨“¾‚ȃAƒ‹ƒeƒBƒƒbƒgƒRƒXƒZƒbƒg‹L”O";
byte[] bs = Encoding.GetEncoding(1252).GetBytes(s1);
string s2 = Encoding.GetEncoding(932).GetString(bs);
And s2 is now "25日お得なアルティャbトコスセット記念", that looks a lot more like Japanese.
What I assume it that some byte array that represent text Shift-JIS encoded, what read by using a different encoding, maybe Windows-1252. So first I try to get back the original byte array. Then I use the proper encoding to get the correct text.
A few notes about my code:
1252 is the numeric ID for Windows-1252, the most usually used-by-mistake encoding. But this is just a guess, you can try with other encodings and see if it makes more sense.
932 is de numeric ID for Shift-JIS (you can also use the string name). This is also a guess, but likely right.
Take into account that using a wrong encoding is not generally a reversible procedure so there may be characters that are lost in the translation.

How do I read and write smart quotes (and other silly characters) in C#

I'm writing a program that reads all the text in a file into a string, loops over that string looking at the characters, and then appends the characters back to another string using a Stringbuilder. The issue I'm having is when it's written back out, the special characters such as “ and ” , come out looking like � characters instead. I don't need to do a conversion, I just want it written back out the way I read it in:
StringBuilder sb = new StringBuilder();
string text = File.ReadAllText(filePath);
for (int i = 0; i < text.Length; ++i) {
if (text[i] != '{') { // looking for opening curly brace
sb.Append(text[i]);
continue;
}
// Do stuff
}
File.WriteAllText(destinationFile, sb.ToString());
I tried using different Encodings (UTF-8, UTF-16, ASCII), but then it just came out even worse; I started getting question mark symbols and Chinese characters (yes, a bit of a shotgun approach, but I was just experimenting).
I did read this article: http://www.joelonsoftware.com/articles/Unicode.html
...but it didn't really explain why I was seeing what I saw, unless in C#, the reader starts cutting off bits when it hits weird characters like that. Thanks in advance for any help!

TL;DR that is definitely not UTF-8 and you are not even using UTF-8 to read the resulting file. Read as Windows1252, write as Windows1252 (If you are going to use the same viewing method to view the resulting file)
Well let's first just say that there is no way a file made by a regular user will be in UTF-8. Not all programs in windows even support it (excel, notepad..), let alone have it as default encoding (even most developer tools don't default to utf-8, which drives me insane). Since a lot of developers don't understand that such a thing as encoding even exists, then what chances do regular users have of saving their files in an utf-8 hostile environment?
This is where your problems first start. According to documentation, the overload you are using File.ReadAllText(filePath); can only detect UTF-8 or UTF-32.
Indeed, simply reading a file encoded normally in Windows-1252 that contains "a”a" results in a string "a�a", where � is the unicode replacement character (Read the wikipedia section, it describes exactly the situation you are in!) used to replace invalid bytes. When the replacement character is again encoded as UTF-8, and interpreted as Windows-1252, you will see � because the bytes for � in UTF-8 are 0xEF, 0xBF, 0xBD which are the bytes for � in Windows-1252.
So read it as Windows-1252 and you're half-way there:
Encoding windows1252 = Encoding.GetEncoding("Windows-1252");
String result = File.ReadAllText(#"C:\myfile.txt", windows1252);
Console.WriteLine(result); //Correctly prints "a”a" now
Because you saw �, the tool you are viewing the newly made file with is also using Windows-1252. So if the goal is to have the file show correct characters in that tool, you must encode the output as Windows-1252:
Encoding windows1252 = Encoding.GetEncoding("Windows-1252");
File.WriteAllText(#"C:\myFile", sb.toString(), windows1252);

Chances are the text will be UTF8.
File.ReadAllText(filePath, Encoding.UTF8)
coupled with
File.WriteAllText(destinationFile, sb.ToString(), Encoding.UTF8)
should cover off dealing with the Unicode characters. If you do one or the other you're going to get garbage output, both or nothing.

Convert UCS-2 characters to UTF-8 Using C#

I'm pulling some internationalized text from a MS SQL Server 2005 database. As per the defaults for that DB, the characters are stored as UCS-2. However, I need to output the data in UTF-8 format, as I'm sending it out over the web. Currently, I have the following code to convert:
SqlString dbString = resultReader.GetSqlString(0);
byte[] dbBytes = dbString.GetUnicodeBytes();
byte[] utf8Bytes = System.Text.Encoding.Convert(System.Text.Encoding.Unicode,
System.Text.Encoding.UTF8, dbBytes);
System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding();
string outputString = encoder.GetString(utf8Bytes);
However, when I examine the output in the browser, it appears to be garbage, no matter what I set the encoding to.
What am I missing?
EDIT:
In response to the answers below, the reason I thought I had to perform a conversion is because I can output literal multibyte strings just fine. For example:
OutputControl.Text = "カルフォルニア工科大学とチューリッヒ工科大学は共同で、太陽光を保管可能な燃料に直接変えることのできる装置の開発に成功したとのこと";
works. Here, OutputControl is an ASP.Net Literal. However,
OutputControl.Text = outputString; //Output from above snippet
results in mangled output as described above. My hypothesis was that the database's output was somehow getting mangled by ASP.Net. If that's not the case, then what are some other possibilities?
EDIT 2:
Okay, I'm stupid. It turns out that there's nothing wrong with the database at all. When I tried inserting my own literal double byte characters (材料,原料;木料), I could read and output them just fine even without any conversion process at all. It seems to me that whatever is inserting the data into the DB is mangling the characters somehow, so I'm going to look at that. With my verified, "clean" data, the following code works:
OutputControl.Text = dbString.ToString();
as the responses below indicate it should.

Your code does essentially the same as:
SqlString dbString = resultReader.GetSqlString(0);
string outputString = dbString.ToString();
string itself is a UNICODE string (specifically, UTF-16, which is 'almost' the same as UCS-2, except for codepoints not fitting into the lowest 16 bits). In other words, the conversions you are performing are redundant.
Your web app most likely mangles the encoding somewhere else as well, or sets a wrong encoding for the HTML output. However, that can't be diagnosed from the information you provided so far.

String in .net is 'encoding agnostic'.
You can convert bytes to string using a particular encoding to tell .net how to interprets your bytes.
You can convert string to bytes using a particular encoding to tell .net how you want your bytes served.
But trying to convert a string to another string using encodings makes no sens at all.

How to get correctly-encoded HTML from the clipboard?

Has anyone noticed that if you retrieve HTML from the clipboard, it gets the encoding wrong and injects weird characters?
For example, executing a command like this:
string s = (string) Clipboard.GetData(DataFormats.Html)
Results in stuff like:
<FONT size=-2>  <A href="/advanced_search?hl=en">Advanced
Search</A><BR>  Preferences<BR>  <A
href="/language_tools?hl=en">Language
Tools</A></FONT>
Not sure how MarkDown will process this, but there are weird characters in the resulting markup above.
It appears that the bug is with the .NET framework. What do you think is the best way to get correctly-encoded HTML from the clipboard?

In this case it is not so visible as it was in my case. Today I tried to copy data from clipboard but there were a few unicode characters. The data I got were as if I would read a UTF-8 encoded file in Windows-1250 encoding (local encoding in my Windows).
It seems you case is the same. If you save the html data (remember to put non-breakable space = 0xa0 after the  character, not a standard space) in Windows-1252 (or Windows-1250; both works). Then open this file as a UTF-8 file and you will see what there should be.
For my other project I made a function that fix data with corrupted encoding.
In this case simple conversion should be sufficient:
byte[] data = Encoding.Default.GetBytes(text);
text = Encoding.UTF8.GetString(data);
My original function is a little bit more complex and contains tests to ensure that data are not corrupted...
public static bool FixMisencodedUTF8(ref string text, Encoding encoding)
{
if (string.IsNullOrEmpty(text))
return false;
byte[] data = encoding.GetBytes(text);
// there should not be any character outside source encoding
string newStr = encoding.GetString(data);
if (!string.Equals(text, newStr)) // if there is any character "outside"
return false; // leave, the input is in a different encoding
if (IsValidUtf8(data) == 0) // test data to be valid UTF-8 byte sequence
return false; // if not, can not convert to UTF-8
text = Encoding.UTF8.GetString(data);
return true;
}
I know that this is not the best (or correct solution) but I did not found any other way how to fix the input...
EDIT: (July 20, 2017)
It Seems like the Microsoft already found this error and now it works correctly. I'm not sure whether the problem is in some frameworks, but I know for sure, that now the application uses a different framework as in time, when I wrote the answer. (Now it is 4.5; the previous version was 2.0)
(Now all my code fails in parsing the data. There is another problem to determine the correct behaviour for application with fix already aplied and without fix.)

You have to interpret the data as UTF-8. See MS Office hyperlinks change code page?.

DataFormats.Html specification states it's encoded in UTF-8. But there's a bug in .NET 4 Framework and lower, and it actually reads as UTF-8 as Windows-1252.
You get allot of wrong encodings, leading funny/bad characters such as
'Å','‹','Å’','Ž','Å¡','Å“','ž','Ÿ','Â','¡','¢','£','¤','Â¥','¦','§','¨','©'
Full explanation here
Debugging Chart Mapping Windows-1252 Characters to UTF-8 Bytes to Latin-1 Characters
Soln: Create a translation dictionary and search and replace.

I don't know what your original source document is, but be aware that Word and Outlook provide several versions of the clipboard in different encodings. One is usually Windows-1252 and another is UTF-8. Possibly you're grabbing the UTF-8 encoded version by default, when you're expecting the Windows-1252 (Latin-1 + Smart Quotes)? Non-ASCII characters would show up as multiple odd Latin-1 accented characters. Most "Smart Quotes" are not in the Latin-1 set and are often three bytes in UTF-8.
Can you specify which encoding you want the clipboard contents in?

Try this:
System.Windows.Forms.Clipboard.GetText(System.Windows.Forms.TextDataFormat.Html);