netcore/System.Private.CoreLib/shared/System/Runtime/CompilerServices/FormattableStringFactory.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 /*============================================================
   6 **
   7 **
   8 **
   9 ** Purpose: implementation of the FormattableStringFactory
  10 ** class.
  11 **
  12 ===========================================================*/
  13
  14 namespace System.Runtime.CompilerServices
  15 {
  16     /// <summary>
  17     /// A factory type used by compilers to create instances of the type <see cref="FormattableString"/>.
  18     /// </summary>
  19     public static class FormattableStringFactory
  20     {
  21         /// <summary>
  22         /// Create a <see cref="FormattableString"/> from a composite format string and object
  23         /// array containing zero or more objects to format.
  24         /// </summary>
  25         public static FormattableString Create(string format, params object?[] arguments)
  26         {
  27             if (format == null)
  28             {
  29                 throw new ArgumentNullException(nameof(format));
  30             }
  31
  32             if (arguments == null)
  33             {
  34                 throw new ArgumentNullException(nameof(arguments));
  35             }
  36
  37             return new ConcreteFormattableString(format, arguments);
  38         }
  39
  40         private sealed class ConcreteFormattableString : FormattableString
  41         {
  42             private readonly string _format;
  43             private readonly object?[] _arguments;
  44
  45             internal ConcreteFormattableString(string format, object?[] arguments)
  46             {
  47                 _format = format;
  48                 _arguments = arguments;
  49             }
  50
  51             public override string Format => _format;
  52             public override object?[] GetArguments() { return _arguments; }
  53             public override int ArgumentCount => _arguments.Length;
  54             public override object? GetArgument(int index) { return _arguments[index]; }
  55             public override string ToString(IFormatProvider? formatProvider) { return string.Format(formatProvider, _format, _arguments); }
  56         }
  57     }
  58 }