html2画布无法单击按钮

Question

我无法单击批准按钮将签名保存到数据库中。 。请帮忙！我已经参考了这个链接，但他们没有工作。 https://www.aspsnippets.com/Articles/Convert-Export-HTML-DIV-or-Table-to-Image-using-HTML-Canvas-in-ASPNet-using-C-and-VBNet.aspx

批准按钮下的代码

<asp:Button ID="ProcesssOwner1" Visible="true" data-action="save" Text="Approve" CssClass="btn btn-success btn-sm" UseSubmitBehavior="false" OnClientClick="return ConvertToImage(this)" runat="server" OnClick="ProcesssOwner1_Click" />

的Javascript

<script type="text/javascript">
        function ConvertToImage(ProcesssOwner1) {

            if (signaturePad.isEmpty()) {
                alert("Please provide signature first.");
                return false;
            } else {
                //document.getElementById("hfSign").value = signaturePad.toDataURL();
                html2canvas($("#drawing")[0]).then(function (canvas) {
                    var base64 = canvas.toDataURL();
                    $("[id*=hfImageData]").val(base64);
                    __doPostBack(ProcesssOwner1.name, "");
                });
                return false;
            }

        }
    </script>

点击按钮下的代码

这里我尝试将签名保存在路径和文件夹中。

 protected void ProcesssOwner1_Click(object sender, EventArgs e)
    {
        if (Session["loggedUserID"] == null && Session["loggedRoleID"] == null)
        {
            Response.Redirect("Login.aspx");
        }
        else
        {

            int loggedUserID = Convert.ToInt32(Session["loggedUserID"]);
            List<BOL.UserInfo> userslist = new UserInfos().List();
            BOL.UserInfo loggeduser = userslist.Where(x => x.UserID == loggedUserID).FirstOrDefault();
            string app_type = "";
            string dcr = Request.QueryString["r_id"].Replace("/", "_") + DateTime.Now.ToString("yyyy-MM-dd HHmmtt");
            string myID = loggeduser.EmployeeNo;
            string path1 = "/Web/";
            //System.Diagnostics.Debugger.Launch();
            if (Request.QueryString["STAT"] == "S_7")
            {
                app_type = "A";
                string base64 = Request.Form[hfImageData.UniqueID].Split(',')[1];
                byte[] bytes = Convert.FromBase64String(base64);
                //write the bytes to file:
                File.WriteAllBytes(path1 + dcr + "_" + myID + app_type + ".jpg", bytes); //write to a temp location.
                File.Copy(path1 + dcr + "_" + myID + app_type + ".jpg", @"D:\IntranetPortal\IntranetPortal\Web\signature\" + dcr + "_" + myID + app_type + ".jpg");//here we grab the file and copy it.                                                                                                                      //EDIT: based on permissions you might be able to write directly to the share instead of a temp folder first.
            }
            
            else if (Request.QueryString["STAT"] == "S_9")
            {
                app_type = "C";
                string base64 = Request.Form[hfImageData.UniqueID].Split(',')[1];
                byte[] bytes = Convert.FromBase64String(base64);
                //write the bytes to file:
                File.WriteAllBytes(path1 + dcr + "_" + myID + app_type + ".jpg", bytes); //write to a temp location.
                File.Copy(path1 + dcr + "_" + myID + app_type + ".jpg", @"D:\IntranetPortal\IntranetPortal\Web\signature\" + dcr + "_" + myID + app_type + ".jpg");//here we grab the file and copy it.
            }
            DAL.DMSS insertdata = new DMSS();
            insertdata.APP_PROCESS(Request.QueryString["r_id"], app_type, chatt.Text, path1 + "signature" + "/" + dcr + "_" + myID + app_type + ".jpg", dcr + "_" + myID + app_type + ".jpg", loggeduser.EmployeeNo, DATEE.Text);
            ScriptManager.RegisterStartupScript(this, this.GetType(), "alert", "alert('Approved.Thank you.');window.location ='Dms_app.aspx';", true);
        }

    }