Interpolation in the middle of a string

Question

I want to interpolation in the middle of a string, but I cannot use String.Format, because the string contains {} curly brackets.

This is what I have tried so far:

string code = "(function(){var myvariable = $"{variableToBeInterpolated}"});"

Returns: ) expected ; expected

Edit: I tried the following snippet, the interpolation is now working, but the code is not executed in the browser.

"(function(){var myvariable=" + $"{myvariable c#}" + ")});"

Why does the string having `{` or `}` in it mean you can't use `string.Format`? Just [escape those characters](https://stackoverflow.com/questions/91362/how-to-escape-braces-curly-brackets-in-a-format-string-in-net). — Kenneth K., Feb 13 '19 at 15:10
When I use string format like this: string.Format ((function () {var myvariable = {0}}), myvariable); returns: contains invalid placeholder — Slinidy, Feb 13 '19 at 15:16
Why are you building up JavaScript via a string in the first place? What's the use care here? — mason, Feb 13 '19 at 15:20
I using cefsharp, method evaluatescript to execute JavaScript — Slinidy, Feb 13 '19 at 15:25

prd · Accepted Answer · 2022-05-12T18:25:02.340

6

General Information

With C# version 6, extensive string interpolation capabilities have been added to the language.

String interpolation provides a more readable and convenient syntax to create formatted strings than a string composite formatting feature.

To solve your problem, please have a look at the special characters section of the documentation, which reads the following:

To include a brace, "{" or "}", in the text produced by an interpolated string, use two braces, "{{" or "}}".

var variable = 10;
var code = $"(function() {{ var myVariable = {variable} }});";
Console.WriteLine(code);

Output: (function() { var myVariable = 10 });

edited May 12 '22 at 18:25

answered Feb 13 '19 at 15:26

prd

If my string contains more brackets, this method work? – Slinidy Feb 13 '19 at 15:46
@Slinidy sure, you just have to escape them. – prd Feb 13 '19 at 15:48

Johnny · Answer 2 · 2019-02-13T20:40:14.577

0

Why do you want to interpolate in the middle, rather put $ in front. And for { you need to use {{. (the same applies for })

string code = $"(function(){{ var myvariable = {myvariable} }});";

edited Feb 13 '19 at 20:40

answered Feb 13 '19 at 15:13

Johnny

The simbol $ has to be in the middle if it does not bug the string because of the brackets – Slinidy Feb 13 '19 at 15:19
This SO post explains escaping curly braces using string.format. (works with string interpolation with $) https://stackoverflow.com/questions/3773857/escape-curly-brace-in-string-format – nick gowdy Feb 13 '19 at 16:07
@nickgowdy tnx for the link. I rollbacked my first answer, which is actually correct one but the point is that I was confused with the actual requerements as @Slinidy said he wants `$` in the middle... – Johnny Feb 13 '19 at 20:42

nick gowdy · Answer 3 · 2019-02-13T16:05:31.667

0

Have you tried:

string someVariable = "test";

string code = $"(function()'{{var myvariable = ({someVariable} in c#)}});"

Using $ in C# is string interpolation. Added in C# 6

edited Feb 13 '19 at 16:05

answered Feb 13 '19 at 15:13

nick gowdy

Did you try compiling this? – Kenneth K. Feb 13 '19 at 15:14
@KennethK.Sorry, my bad. You have to do double {{ }} otherwise it's a compilation error. Check my updated answer. I can't guarantee it will work at runtime, you'll need to try it out. – nick gowdy Feb 13 '19 at 16:05