Post 提交用户名和密码， 用户自动登录，无需手动登录

   public void AutoPost(string url,string domain, string userName)
        {
            AlipayProxy.UserReg.UserReg userRegService = new AlipayProxy.UserReg.UserReg();
            string password = userRegService.GetUserPassWord(userName);
            string language = "zh-cn";
            string key = "VaNclddf&123";// 解密key
            string decrypassword = Decrypt(password, key);
            StringBuilder sbForm = new StringBuilder();
            sbForm.Append("<form id='postForm' method='post'> ");
            sbForm.Append("<input type='hidden' name='Domain' value='" + domain + "' />");
            sbForm.Append("<input type='hidden' name='UserName' value='" + userName + "' />");
            sbForm.Append("<input type='hidden' name='Password' value='" + decrypassword + "' />");
            sbForm.Append("<input type='hidden' name='Language' value='" + language + "' />");
            sbForm.Append("</form>");
            sbForm.Append("<script language= 'javascript'>");
            sbForm.Append("document.getElementById('postForm').method = 'post';");
            sbForm.Append("document.getElementById('postForm').action = '" + url + "';");
            sbForm.Append("document.getElementById('postForm').submit();");
            sbForm.Append("</script>");
            Response.Write(sbForm.ToString());
        }

AutoPost("Login.aspx", "Vancloud-corp", username);

login 页面做如下处理

   if (!IsPostBack)
            {
                if (Request.RequestType.ToUpper() == "POST")
                {
                    SortedList table = Param();
                    if (table != null)
                    {
                          AlipayProxy.UserReg.UserReg userRegService = new AlipayProxy.UserReg.UserReg();
                            if (true == userRegService.UserLogin( table["Domain"].ToString(),table["UserName"].ToString(),table["Password"].ToString()))
                            {
                                int role = 0;
                                if (!SaveLoginInfo(  table["Domain"].ToString(),table["UserName"].ToString(),table["Password"].ToString(),table["Language"].ToString(),out role))
                                {
                                    lblErrorMessage.Text = GetLocalResourceObject("PermissionExpired").ToString();
                                    return;
                                }

                                Response.Redirect("SysInit.aspx", false);
                            }
                    }
                } 
}