public class Demo<T>
{
 public Demo(Action<T> demo)
 {
  _demo = demo ?? throw new ArgumentNullException(nameof(action));
 }

 private Action<T> _demo;

 public async Task<T> DoAsync(T t)
 {
  // 做某些事情。
 }

 // 做其他事情。
}

public class Demo<T1, T2>
{
 public Demo(Action<T1, T2> demo)
 {
  _demo = demo ?? throw new ArgumentNullException(nameof(action));
 }

 private Action<T1, T2> _demo;

 public async Task<(T1, T2)> DoAsync(T1 t1, T2 t2)
 {
  // 做某些事情。
 }

 // 做其他事情。
}

<#@ output extension=".txt" #> 
<#@ assembly name="System.Xml" #> 
<# 
 System.Xml.XmlDocument configurationData = ...; // Read a data file here. 
#> 
namespace Fabrikam.<#= configurationData.SelectSingleNode("jobName").Value #> 
{ 
 ... // More code here. 
} 

using System;
using System.Linq;
using static System.Environment;

namespace Walterlv.BuildTools
{
 public class GenericTypeGenerator
 {
  private static readonly string GeneratedHeader =
$@"http://------------------------------------------------------------------------------
// <auto-generated>
//  此代碼由工具生成。
//  運(yùn)行時(shí)版本:{Environment.Version.ToString(4)}
//
//  對(duì)此文件的更改可能會(huì)導(dǎo)致不正確的行為，并且如果
//  重新生成代碼，這些更改將會(huì)丟失。
// </auto-generated>
//------------------------------------------------------------------------------

#define GENERATED_CODE
";

  private static readonly string GeneratedFooter =
   $@"";

  private readonly string _genericTemplate;
  private readonly string _toolName;

  public GenericTypeGenerator(string toolName, string genericTemplate)
  {
   _toolName = toolName ?? throw new ArgumentNullException(nameof(toolName));
   _genericTemplate = genericTemplate ?? throw new ArgumentNullException(nameof(toolName));
  }

  public string Generate(int genericCount)
  {
   var toolName = _toolName;
   var toolVersion = "1.0";
   var GeneratedAttribute = $"[System.CodeDom.Compiler.GeneratedCode(\"{toolName}\", \"{toolVersion}\")]";

   var content = _genericTemplate
    // 替換泛型。
    .Replace("<out T>", FromTemplate("<{0}>", "out T{n}", ", ", genericCount))
    .Replace("Task<T>", FromTemplate("Task<({0})>", "T{n}", ", ", genericCount))
    .Replace("Func<T, Task>", FromTemplate("Func<{0}, Task>", "T{n}", ", ", genericCount))
    .Replace(" T, Task>", FromTemplate(" {0}, Task>", "T{n}", ", ", genericCount))
    .Replace("(T, bool", FromTemplate("({0}, bool", "T{n}", ", ", genericCount))
    .Replace("var (t, ", FromTemplate("var ({0}, ", "t{n}", ", ", genericCount))
    .Replace(", t)", FromTemplate(", {0})", "t{n}", ", ", genericCount))
    .Replace("return (t, ", FromTemplate("return ({0}, ", "t{n}", ", ", genericCount))
    .Replace("<T>", FromTemplate("<{0}>", "T{n}", ", ", genericCount))
    .Replace("(T value)", FromTemplate("(({0}) value)", "T{n}", ", ", genericCount))
    .Replace("(T t)", FromTemplate("({0})", "T{n} t{n}", ", ", genericCount))
    .Replace("(t)", FromTemplate("({0})", "t{n}", ", ", genericCount))
    .Replace("var t =", FromTemplate("var ({0}) =", "t{n}", ", ", genericCount))
    .Replace(" T ", FromTemplate(" ({0}) ", "T{n}", ", ", genericCount))
    .Replace(" t;", FromTemplate(" ({0});", "t{n}", ", ", genericCount))
    // 生成 [GeneratedCode]。
    .Replace(" public interface ", $" {GeneratedAttribute}{NewLine} public interface ")
    .Replace(" public class ", $" {GeneratedAttribute}{NewLine} public class ")
    .Replace(" public sealed class ", $" {GeneratedAttribute}{NewLine} public sealed class ");
   return GeneratedHeader + NewLine + content.Trim() + NewLine + GeneratedFooter;
  }

  private static string FromTemplate(string template, string part, string separator, int count)
  {
   return string.Format(template,
    string.Join(separator, Enumerable.Range(1, count).Select(x => part.Replace("{n}", x.ToString()))));
  }
 }
}

using System.IO;
using System.Linq;
using System.Text;
using Walterlv.BuildTools;

class Program
{
 static void Main(string[] args)
 {
  foreach (var argument in args)
  {
   GenerateGenericTypes(argument, 4);
  }
 }

 private static void GenerateGenericTypes(string file, int count)
 {
  // 讀取原始文件并創(chuàng)建泛型代碼生成器。
  var template = File.ReadAllText(file, Encoding.UTF8);
  var generator = new GenericTypeGenerator(template);

  // 根據(jù)泛型個(gè)數(shù)生成目標(biāo)文件路徑和文件內(nèi)容。
  var format = GetIndexedFileNameFormat(file);
  (string targetFileName, string targetFileContent)[] contents = Enumerable.Range(2, count - 1).Select(i =>
   (string.Format(format, i), generator.Generate(i))
  ).ToArray();

  // 寫(xiě)入目標(biāo)文件。
  foreach (var writer in contents)
  {
   File.WriteAllText(writer.targetFileName, writer.targetFileContent);
  }
 }

 private static string GetIndexedFileNameFormat(string fileName)
 {
  var directory = Path.GetDirectoryName(fileName);
  var name = Path.GetFileNameWithoutExtension(fileName);
  if (name.EndsWith("1"))
  {
   name = name.Substring(0, name.Length - 1);
  }

  return Path.Combine(directory, name + "{0}.cs");
 }
}

"$(ProjectDir)..\CodeGenerator\$(OutDir)net47\CodeGenerator.exe" "$(ProjectDir)..\Walterlv.Demo\Generic\IDemoFile.cs" "$(ProjectDir)..\..\Walterlv.Demo\Generic\DemoFile.cs"