.NET循环遍历文件夹下所有文件.改所有文件的文件名后缀名

上代码 

using System.Collections.Specialized;


string strfilenames = "";
StringCollection sc01 = GetAllFiles(@"E:\Pro\MyProjectJianjie\MyProject\bd");
for (int i = 0; i < sc01.Count; i++)
{
	//Console.WriteLine($"当前索引：{i},元素【{sc01[i]}】");
	strfilenames += sc01[i] + "-";

	string strout;
	strout = "";
	if (!File.Exists(System.Web.HttpContext.Current.Server.MapPath(urlconvertor(sc01[i]))))
	{
	}
	else
	{
		StreamReader sr = new StreamReader(System.Web.HttpContext.Current.Server.MapPath(urlconvertor(sc01[i])), System.Text.Encoding.Default);
		String input = sr.ReadToEnd();
		sr.Close();
		strout = input;
		if (strout.IndexOf("")>=0)
		{
			//string path = System.Web.HttpContext.Current.Server.MapPath(urlconvertor(sc01[i]));
			FileInfo fi = new FileInfo(sc01[i]);
			if (fi.Exists)
			{
				fi.MoveTo(Server.MapPath(urlconvertor(sc01[i])+"123456"));
				//Response.Write("<script>alert(\"文件改名成功\");</script>");
			}
		}
		string a02 = "";
	}

}

string a01 = "";


/// <summary>
/// 遍历 rootdir目录下的所有文件
/// </summary>
/// <param name="rootdir">目录名称</param>
/// <returns>该目录下的所有文件</returns>
public StringCollection GetAllFiles(string rootdir)
{
	StringCollection result = new StringCollection();
	GetAllFiles(rootdir, result);
	return result;
}
/// <summary>
/// 作为遍历文件函数的子函数
/// </summary>
/// <param name="parentDir">目录名称</param>
/// <param name="result">该目录下的所有文件</param>
public void GetAllFiles(string parentDir, StringCollection result)
{
	//获取目录parentDir下的所有的子文件夹
	string[] dir = Directory.GetDirectories(parentDir);
	for (int i = 0; i < dir.Length; i++)
		GetAllFiles(dir[i], result);

	//获取目录parentDir下的所有的文件，并过滤得到所有的文本文件
	string[] file = Directory.GetFiles(parentDir, "*");
	for (int i = 0; i < file.Length; i++)
	{
		//FileInfo fi = new FileInfo(file[i]);
		//if (fi.Extension.ToLower() == "txt")
		//{
		result.Add(file[i]);
		//}                
	}
}

private string urlconvertor(string imagesurl1)
{
	string tmpRootDir = Server.MapPath(System.Web.HttpContext.Current.Request.ApplicationPath.ToString());//获取程序根目录
	string imagesurl2 = imagesurl1.Replace(tmpRootDir, ""); //转换成相对路径
	imagesurl2 = imagesurl2.Replace(@"\", @"/");
	//imagesurl2 = imagesurl2.Replace(@"Aspx_Uc/", @"");
	return imagesurl2;
}