private void button1_Click(object sender, EventArgs e)
        {
            string filePath = textBox1.Text.Trim();
            string directoryName = filePath.Substring(0, filePath.LastIndexOf("\\"));//根據文件路徑獲取到該文件夾
            string dir = Path.GetDirectoryName(filePath);   //獲取文件所在的目錄
            string fileName = Path.GetFileName(filePath);   //獲取文件名，帶后綴
            string fileNameNoExt = Path.GetFileNameWithoutExtension(filePath); //獲取文件名，不帶后綴
            string ExtName = Path.GetExtension(filePath);   //獲取文件的后綴名
            string[] Files = Directory.GetFiles(dir, "*.Png");  //獲取該目錄下所有以后綴名為Png結尾的文件
            List<string> files = new List<string>();
            foreach (var f in Files)
            {
                string nameFull = Path.GetFileNameWithoutExtension(f);
                string name = nameFull.Substring(0, nameFull.LastIndexOf("_"));
                if (fileNameNoExt == name)
                    files.Add(f);
            }
            string str = string.Join(",", files.ToArray());//以"，"存在于str中
        }