private void SignByPlatform(string documentId)
{
// 平台签署,带签名外观
string sealId = "2292201504040435826"; // 平台印章，在契约锁云平台维护
Stamper stamper = new Stamper(1, 0.5f, 0.5f); // 签名位置，根据坐标比确定位置
//Stamper stamper = new Stamper("公章：", 0, 0);// 签名位置，根据关键字定位
//remoteSignService.Sign(documentId);//无签名外观
signService.Sign(documentId, sealId, stamper);
Console.WriteLine("平台签署成功！");
}