List SerchName = new List(); //要查找的字段
     public List SerchName1
     {
       get { return SerchName; }
       set { SerchName = value; }
}

//设置查找文件类型
     private int i;
     public int I
     {
       get { return i; }
       set { i = value; }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
namespace Serch_File
{
   class FindFile
{
    public List lst1 = new List();
     public List getFile(string path, string extName, int i)//创建一个List类型的函数 
    {
      getdir(path, extName, i);//传入路径、搜索的字段 、将要搜索的类型
      return lst1;
    }
     private void getdir(string path, string extName, int i)
     {
       try
       {
         //获取文件夹列表
         string[] dirs = Directory.GetDirectories(path);　　　　　　　　　　　 DirectoryInfo fdir = new DirectoryInfo(path);
         FileInfo[] file = fdir.GetFiles();
         //当前目录文件或目录不为空
         if (file.Length != 0 || dirs.Length != 0)
         {
           foreach (FileInfo f in file)
           {
             switch (i)
            {
              case 0: if (extName == f.Name) //根据文件名匹配上
                {
                  lst1.Add(f.Name);
                 } break;
              case 1: if (extName == f.Extension) //根据后缀名匹配上
                 {
                   lst1.Add(f.FullName);
                 } break;
             }
           }
           foreach (string d in dirs)
           {
             getdir(d, extName, i);//递归   
           }
         }
       }
       catch
       {
 
       }
     }
   }
}