Develop Reference

*Very specific issue* of removing white spaces from multiple lines of a single string in C#. Trim() not working

I am working with C#. I had a string which was in the format:
myString = ""Person:Name","Address:City","University:District""
I know having quotes within a main string quote is not right in C# and that you have to escape quotes. But this string that I have here is the result of concatenation of several strings to make it look like that for some back-end processing.It was a string list of the format [A:B, C:D, E:F] which was converted into JSON format and then back to string again. I stripped off the external brackets already in case you're wondering. So before moving further, I'd like to clarify that this is a legal string and the quotes within the string are not a problem in this particular scenario.
I want my final output to display in multiple lines like the following:
Person:Name
Address:City
University:District
I tried to achieve it by doing the following:
myString = myString.Replace(',', '\n'); //replaced comma with newline
myString = myString.Replace('"', ' '); //replaced double quote with a space
I have them in separate lines now, however my problem now is I can't seem to get rid of the space. I want all of the spaces removed. i.e 6 total below. Turns out Trim() does not help me. Is there a way to solve this? This is where I am at right now. I'm open to trying any new idea if my way is not correct. If you're confused with the way the string is, you can ask me.
(space)Person:Name(space)
(space)Address:City(space)
(space)University:District(space)

You are replacing double quotes with a space here.
myString = myString.Replace('"', ' ');
It should be like this :
myString = myString.Replace('"', '');

C# string format error

I need to send the value I receive from the model with this link, the proposalName field must be in quotes.How can I do it?
Here is my service url.
string path = string.Format("{ProposalId:{proposalId},ProposalName:{"proposalName"},VendorId:{vendorId}}",
Uri.EscapeDataString(proposalId.ToString()),
Uri.EscapeDataString(proposalName),
Uri.EscapeDataString(vendorId.ToString()));

You can simply put quotes around by escaping the quotes, like this -
string path = string.Format("{{0},ProposalName:\"{1}\",VendorId:{2}}",
Uri.EscapeDataString(proposalId.ToString()),
Uri.EscapeDataString(proposalName),
Uri.EscapeDataString(vendorId.ToString()));
As per your updated question, if you need to pass double quotes in URL, you need to encode it to %22
You can also use URI which allows a lot of flexibility with urls. For example -
Uri myUri = new Uri("http://google.com/search?hl=en&q=\"query with quotes\"");
Going with your example - Replace EscapeDataString with Uri.EscapeUriString. It will escape the chracter to form a valid URL. " will get replaced by %22
Some suggestions here and here-

Your problem exactlly in the {"1"} part. The double quotation mark " should be outside the {}, not inside them.
here is the fixed code.
string path = string.Format("{{0},ProposalName:\"{1}\",VendorId:{2}}",
Uri.EscapeDataString(proposalId.ToString()),
Uri.EscapeDataString(proposalName),
Uri.EscapeDataString(vendorId.ToString()));
or
string path = string.Format(#"{{0},ProposalName:""{1}"",VendorId:{2}}",
Uri.EscapeDataString(proposalId.ToString()),
Uri.EscapeDataString(proposalName),
Uri.EscapeDataString(vendorId.ToString()));
and if you are using C# 6 then you can write it as following
string path = $"{Uri.EscapeDataString(proposalId.ToString())},ProposalName:\"{Uri.EscapeDataString(proposalName)}\",VendorId:{Uri.EscapeDataString(vendorId.ToString())}";

This might do the trick for you
\"{1}\"
instead of
{"1"}
because you can put \ symbol to indicate escape sequence followed by a reserved characters
So
string.Format("{{{0},ProposalName:\"{1}\",VendorId:{2}}}",

I think escaping the quotes and placing them outside the brackets will work:
"{{0},ProposalName:\"{1}\",VendorId:{2}}"
Depending on the C# version, you can also do it like this, which I often think is an easier and cleaner way to do it:
string path = $"{proposalId},ProposalName:\"{proposalName}\",VendorId:{vendorId}";

You have two problems:
Wrong quotation (should be outside the braces {...} and escaped)
Incorrect { and } escape: {{ means just a single '{' in a formatting string
Should be
string path = string.Format("{{{0},ProposalName:\"{1}\",VendorId:{2}}}",
please, notice
escaped quotations \" which are outside {1}
tripled curly braces{{{ and }}}
Edit: in your edited question you have the same errors:
string format =
"http://mobile.teklifdosyam.com/VendorReport/GetListProposalService?&page=1&start=0&limit=10&filter=" +
"{{ProposalId:{0},ProposalName:\"{1}\",VendorId:{2}}}";
string path = string.Format(format,
Uri.EscapeDataString(proposalId.ToString()),
Uri.EscapeDataString(proposalName),
Uri.EscapeDataString(vendorId.ToString()));
please, notice escaped quotations \" which are outside the {1}, double '{{' and tripled '}}}'. When formatting you have to use numbers as place holders: so {"proposalName"} must be changed into {0}

Outputting c# console application to webpage [duplicate]

Is there an easy way to create a multiline string literal in C#?
Here's what I have now:
string query = "SELECT foo, bar"
+ " FROM table"
+ " WHERE id = 42";
I know PHP has
<<<BLOCK
BLOCK;
Does C# have something similar?

You can use the # symbol in front of a string to form a verbatim string literal:
string query = #"SELECT foo, bar
FROM table
WHERE id = 42";
You also do not have to escape special characters when you use this method, except for double quotes as shown in Jon Skeet's answer.

It's called a verbatim string literal in C#, and it's just a matter of putting # before the literal. Not only does this allow multiple lines, but it also turns off escaping. So for example you can do:
string query = #"SELECT foo, bar
FROM table
WHERE name = 'a\b'";
This includes the line breaks (using whatever line break your source has them as) into the string, however. For SQL, that's not only harmless but probably improves the readability anywhere you see the string - but in other places it may not be required, in which case you'd either need to not use a multi-line verbatim string literal to start with, or remove them from the resulting string.
The only bit of escaping is that if you want a double quote, you have to add an extra double quote symbol:
string quote = #"Jon said, ""This will work,"" - and it did!";

As a side-note, with C# 6.0 you can now combine interpolated strings with the verbatim string literal:
string camlCondition = $#"
<Where>
<Contains>
<FieldRef Name='Resource'/>
<Value Type='Text'>{(string)parameter}</Value>
</Contains>
</Where>";

The problem with using string literal I find is that it can make your code look a bit "weird" because in order to not get spaces in the string itself, it has to be completely left aligned:
var someString = #"The
quick
brown
fox...";
Yuck.
So the solution I like to use, which keeps everything nicely aligned with the rest of your code is:
var someString = String.Join(
Environment.NewLine,
"The",
"quick",
"brown",
"fox...");
And of course, if you just want to logically split up lines of an SQL statement like you are and don't actually need a new line, you can always just substitute Environment.NewLine for " ".

One other gotcha to watch for is the use of string literals in string.Format. In that case you need to escape curly braces/brackets '{' and '}'.
// this would give a format exception
string.Format(#"<script> function test(x)
{ return x * {0} } </script>", aMagicValue)
// this contrived example would work
string.Format(#"<script> function test(x)
{{ return x * {0} }} </script>", aMagicValue)

Why do people keep confusing strings with string literals? The accepted answer is a great answer to a different question; not to this one.
I know this is an old topic, but I came here with possibly the same question as the OP, and it is frustrating to see how people keep misreading it. Or maybe I am misreading it, I don't know.
Roughly speaking, a string is a region of computer memory that, during the execution of a program, contains a sequence of bytes that can be mapped to text characters. A string literal, on the other hand, is a piece of source code, not yet compiled, that represents the value used to initialize a string later on, during the execution of the program in which it appears.
In C#, the statement...
string query = "SELECT foo, bar"
+ " FROM table"
+ " WHERE id = 42";
... does not produce a three-line string but a one liner; the concatenation of three strings (each initialized from a different literal) none of which contains a new-line modifier.
What the OP seems to be asking -at least what I would be asking with those words- is not how to introduce, in the compiled string, line breaks that mimick those found in the source code, but how to break up for clarity a long, single line of text in the source code without introducing breaks in the compiled string. And without requiring an extended execution time, spent joining the multiple substrings coming from the source code. Like the trailing backslashes within a multiline string literal in javascript or C++.
Suggesting the use of verbatim strings, nevermind StringBuilders, String.Joins or even nested functions with string reversals and what not, makes me think that people are not really understanding the question. Or maybe I do not understand it.
As far as I know, C# does not (at least in the paleolithic version I am still using, from the previous decade) have a feature to cleanly produce multiline string literals that can be resolved during compilation rather than execution.
Maybe current versions do support it, but I thought I'd share the difference I perceive between strings and string literals.
UPDATE:
(From MeowCat2012's comment) You can. The "+" approach by OP is the best. According to spec the optimization is guaranteed: http://stackoverflow.com/a/288802/9399618

Add multiple lines : use #
string query = #"SELECT foo, bar
FROM table
WHERE id = 42";
Add String Values to the middle : use $
string text ="beer";
string query = $"SELECT foo {text} bar ";
Multiple line string Add Values to the middle: use $#
string text ="Customer";
string query = $#"SELECT foo, bar
FROM {text}Table
WHERE id = 42";

You can use # and "".
string sourse = #"{
""items"":[
{
""itemId"":0,
""name"":""item0""
},
{
""itemId"":1,
""name"":""item1""
}
]
}";

In C# 11 [2022], you will be able to use Raw String literals.
The use of Raw String Literals makes it easier to use " characters without having to write escape sequences.
Solution for OP:
string query1 = """
SELECT foo, bar
FROM table
WHERE id = 42
""";
string query2 = """
SELECT foo, bar
FROM table
WHERE id = 42
and name = 'zoo'
and type = 'oversized "jumbo" grand'
""";
More details about Raw String Literals
See the Raw String Literals GitHub Issue for full details; and Blog article C# 11 Preview Updates – Raw string literals, UTF-8 and more!

I haven't seen this, so I will post it here (if you are interested in passing a string you can do this as well.) The idea is that you can break the string up on multiple lines and add your own content (also on multiple lines) in any way you wish. Here "tableName" can be passed into the string.
private string createTableQuery = "";
void createTable(string tableName)
{
createTableQuery = #"CREATE TABLE IF NOT EXISTS
["+ tableName + #"] (
[ID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
[Key] NVARCHAR(2048) NULL,
[Value] VARCHAR(2048) NULL
)";
}

Yes, you can split a string out onto multiple lines without introducing newlines into the actual string, but it aint pretty:
string s = $#"This string{
string.Empty} contains no newlines{
string.Empty} even though it is spread onto{
string.Empty} multiple lines.";
The trick is to introduce code that evaluates to empty, and that code may contain newlines without affecting the output. I adapted this approach from this answer to a similar question.
There is apparently some confusion as to what the question is, but there are two hints that what we want here is a string literal not containing any newline characters, whose definition spans multiple lines. (in the comments he says so, and "here's what I have" shows code that does not create a string with newlines in it)
This unit test shows the intent:
[TestMethod]
public void StringLiteralDoesNotContainSpaces()
{
string query = "hi"
+ "there";
Assert.AreEqual("hithere", query);
}
Change the above definition of query so that it is one string literal, instead of the concatenation of two string literals which may or may not be optimized into one by the compiler.
The C++ approach would be to end each line with a backslash, causing the newline character to be escaped and not appear in the output. Unfortunately, there is still then the issue that each line after the first must be left aligned in order to not add additional whitespace to the result.
There is only one option that does not rely on compiler optimizations that might not happen, which is to put your definition on one line. If you want to rely on compiler optimizations, the + you already have is great; you don't have to left-align the string, you don't get newlines in the result, and it's just one operation, no function calls, to expect optimization on.

If you don't want spaces/newlines, string addition seems to work:
var myString = String.Format(
"hello " +
"world" +
" i am {0}" +
" and I like {1}.",
animalType,
animalPreferenceType
);
// hello world i am a pony and I like other ponies.
You can run the above here if you like.

using System;
namespace Demo {
class Program {
static void Main(string[] args) {
string str = #"Welcome User,
Kindly wait for the image to
load";
Console.WriteLine(str);
}
}
}
Output
Welcome User,
Kindly wait for the image to
load

String escaping

I want find and replace a substring in a string in C#.
The substring I want to find looks like this:
],\"
and the substring i want to replace looks like this ],\"Name
This is what i tried so far:
string find = #"],\""";
string replace = #"],\""Name";
string newjson = jsonstring.Replace( find, replace );

From your comment
Debugger show me like this "],\\\"Name"
That is the correct output, the debugger is showing you the escaped version of your string. the \\ turns in to a single \ and the \" turns in to a " once the escaping has been applied.
If you click the magnifying glass in the box in your debugger it will open a new window with the escaping applied.

Are you getting any errors when doing what you did?
Otherwise try without using a literal "#"
so something like this:
string find = "],\\\"";
string replace = "],\\\"Name";
string newjson = jsonstring.Replace(find, replace);
Sometime double quotes and string literals still give me issues so I do it that way without using the literal. Hope that helps.

Mysteriously added quotation mark inside a string

I copied and pasted a certain source code into my program with a text editor. I basically need to confirm that the source code begins with "int main()" so I went ahead and compared line with "int main()" but the comparison always returned false.
I decided to strip the string into characters and found something weird.
so string line has "int main()" passed inside it which is the text that has been pasted inside the text editor. You would think a and b would have the same characters, but they don't:
I'm honestly not sure where is that quotation mark in the beginning coming from. The original string didn't contain it, the debugger doesn't show it (It would display "\"int main()\"" otherwise). What is happening here?
Edit: I tried line = line.Trim(). Still that character is not gone. Apparently it's some special unicode character for Zero width no-break space. How can I remove this from my string?

65279 looks like the decimal representation of a UTF-16 BOM (U+FEFF), is it possible that the way you're reading the data into "line" would've failed to remove it?

Could you set line to line.Trim(); It's hard to tell what might be going on without seeing how line is set.
update based on the BOM character: try line.Trim(new char[]{'\uFEFF'}); assuming .NET 4

I've found the solution:
private readonly string BYTE_ORDER_MARK_UTF8 = Encoding.UTF8.GetString(Encoding.UTF8.GetPreamble());
...
if (line.StartsWith(BYTE_ORDER_MARK_UTF8))
line = line.Remove(0, BYTE_ORDER_MARK_UTF8.Length);
That was bizzare...

In that code you have posted, it seems like the line variable begins with a space character. Try line = line.Trim();
Edit:
The reason the string.Trim() method is not working as expected can found on MSDN
Starting with the .NET Framework 4, the method trims all Unicode white-space characters (that is, characters that produce a true return value when they are passed to the Char.IsWhiteSpace method). Because of this change, the Trim method in the .NET Framework 3.5 SP1 and earlier versions removes two characters, ZERO WIDTH SPACE (U+200B) and ZERO WIDTH NO-BREAK SPACE (U+FEFF), that the Trim method in the .NET Framework 4 and later versions does not remove.
(U+FEFF) seems to be the character at the beginning of line, hence why Trim isn't dealing with it.