Escape curly brace '{' in String.Format [duplicate]
Use double braces {{ or }} so your code becomes:
sb.AppendLine(String.Format("public {0} {1} {{ get; private set; }}",
prop.Type, prop.Name));
// For prop.Type of "Foo" and prop.Name of "Bar", the result would be:
// public Foo Bar { get; private set; }