/// <summary>
        /// 拷贝文件到另一个文件夹下
        /// </summary>
        /// <param name="sourceName">新文件路径</param>
        /// <param name="folderPath">需替换的文件夹路径1</param>
        ///<param name="str3">需替换的文件夹路径2</param>
        public void CopyToFile(string sourceName, string folderPath, string str3)
        {
            try
            {

                if (!Directory.Exists(folderPath))
                {
                    Directory.CreateDirectory(folderPath);
                }

                //当前文件如果不用新的文件名，那么就用原文件文件名
                string fileName = Path.GetFileName(sourceName);
                //这里可以给文件换个新名字，如下：
                //string fileName = string.Format("{0}.{1}", "newFileText", "txt");

                //目标整体路径
                string targetPath = Path.Combine(folderPath, fileName);
                string targetPath2 = Path.Combine(str3, fileName);
                //Copy到新文件下
                FileInfo file = new FileInfo(sourceName);
                if (file.Exists)
                {
                    //true 为覆盖已存在的同名文件，false 为不覆盖
                    file.CopyTo(targetPath, true);
                    file.CopyTo(targetPath2, true);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("异常错误" + ex.Message);
            }
        }