Page 197 - CSharp/C#

var fooBar = (from DataRow x in fooBarTable.Rows
select string.Format("{0}{1}", x["foo"], x["bar"])).ToList();

Can be re-written as:

var fooBar = (from DataRow x in fooBarTable.Rows
select $"{x["foo"]}{x["bar"]}").ToList();

Reusable Interpolated Strings

With string.Format, you can create reusable format strings:

public const string ErrorFormat = "Exception caught:\r\n{0}";

// ...

Logger.Log(string.Format(ErrorFormat, ex));

Interpolated strings, however, will not compile with placeholders referring to non-existent variables.
The following will not compile:

public const string ErrorFormat = $"Exception caught:\r\n{error}";
// CS0103: The name 'error' does not exist in the current context

Instead, create a Func<> which consumes variables and returns a String:

public static Func<Exception, string> FormatError =
error => $"Exception caught:\r\n{error}";

// ...

Logger.Log(FormatError(ex));

String interpolation and localization

If you’re localizing your application you may wonder if it is possible to use string interpolation along
with localization. Indeed, it would be nice to have the possibility to store in resource files Strings
like:

"My name is {name} {middlename} {surname}"

instead of the much less readable:

"My name is {0} {1} {2}"

String interpolation process occurs at compile time, unlike formatting string with string.Format

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