Question

Is there a (system library) way to insert a formatted string to a StringBuilder that will be identical to the following?

myStringBuilder.Insert(0, string.Format("%02X", someInt)); 

I haven’t find any in the class documentation.

Answer 1

StringBuilder provides you the method AppendFormat which does the append and the format in one call but adds the content in the end of the buffer.

In your specific case since there is no provided .NET framework method which does InsertFormat as you wish you either use the method shown above in your question or create an extension method (for example call it InsertFormat) and then use it in your project.