Difference between String, FormattableString, IFormattable
FormattableString is a new type in .NET 4.6, and the compiler will only use it if you try to use it. In other words, the type of an interpolated string literal is normally string – built with string.Format – but can be FormattableString (via FormattableStringFactory) if you ask for it. A FormattableString consists of the … Read more