无法在 ASP.NET 中集成 reCAPTCHA v2（服务器端）

Question

我们在 ASP.NET 项目中使用了 reCAPTCHA，并将验证码从 ascx 发送到代码隐藏页面（服务器端），没有任何问题。然而，在2018年3月之后，我们不得不将验证码更新到v2并进行以下更改：

用户控制 (cs):

....
protected Recaptcha.Web.UI.Controls.Recaptcha Captcha;
protected override Recaptcha.Web.UI.Controls.Recaptcha ReCaptcha 
    { get { return this.Captcha; } }

protected void btnSend_Click(object sender, EventArgs e)
{
    if (this.Submit(sender))
        this.mvMain.ActiveViewIndex++;
}

reCAPTCHA v1 (ascx): 在此版本中，站点密钥在 web.config.

中定义

<%@ Control Language="C#" AutoEventWireup="true" Inherits="Tools.WebUI._ContactForm"%>

<%@ Register Assembly="Recaptcha.Web" Namespace="Recaptcha.Web.UI.Controls" TagPrefix="cc1"%>

<asp:MultiView ID="mvMain" ActiveViewIndex="0" runat="server">
    <asp:View runat="server">
        <div id="divCaptcha">

            <!-- code omitted for brevity -->

            <div id="captcha">
                <cc1:Recaptcha ID="Captcha" Theme="Clean" runat="server" />

            </div>
            <asp:TextBox ID="txtBotCheck" style="display:none !important" runat="server" />
            <asp:Button ID="btnSend" runat="server" OnClick="btnSend_Click" />
            <asp:Label ID="lblMessage" runat="server" CssClass="captchaMessage"></asp:Label>
        </div>
    </asp:View>
    <asp:View runat="server">
        Message was sent...
    </asp:View>
</asp:MultiView>

reCAPTCHA v2 (ascx):

<%@ Control Language="C#" AutoEventWireup="true" Inherits="Crema.Tools.WebUI._ContactForm"%>

<%@ Register Assembly="Recaptcha.Web" Namespace="Recaptcha.Web.UI.Controls" TagPrefix="cc1"%>

<asp:MultiView ID="mvMain" ActiveViewIndex="0" runat="server">
    <asp:View runat="server">

    <script src="http://www.google.com/recaptcha/api.js" async defer></script> 

        <div id="divCaptcha">

            <!-- code omitted for brevity -->

            <div id="captcha">
                <div class="g-recaptcha" data-sitekey="tlcUAAACV...............FhQ"></div>     
            </div>

            <asp:TextBox ID="txtBotCheck" style="display:none !important" runat="server" />
            <asp:Button ID="btnSend" runat="server" OnClick="btnSend_Click" />
            <asp:Label ID="lblMessage" runat="server" CssClass="captchaMessage"></asp:Label>
        </div>
    </asp:View>
    <asp:View runat="server">
        Message was sent...
    </asp:View>
</asp:MultiView>

发送此表单时，我们遇到错误 pge，相关日志中有以下错误。另一方面，当我们查看 Firebug 网络时，我们观察到 g-recaptcha-response，但即使我们使用 "name" 属性 名称="captcha"。

异常信息：

Exception type: NullReferenceException Exception message: Object reference not set to an instance of an object. at Tools.Domain.FormUserControl.Submit(Object sender) at Tools.WebUI._ContactForm.btnSend_Click(Object sender, EventArgs e) at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

有什么想法吗？

Answer 1

我按照这个很棒的教程在 ASP.NET WebForms 中实现了 reCaptcha v2：

https://www.aspsnippets.com/Articles/Google-RECaptcha-Code-with-Example-in-ASPNet.aspx

P.S.: 这家伙有很多很棒的技巧和文章，我会不时查看。