Thanks for the tutorial, Mitch (and many of your others, too!). I took over a module that uses Captcha from someone that had obviously read and used your tutorial. We used it successfully on all DNN versions 4.6 though 4.9.
Starting with a clean install of 5.0, I have successfully installed our Captcha module, and added that module to our custom Enrollment (registration) page. The module is primarily an asp:wizard control, and the Captcha control is on one of the latter .ascx's the wizard steps through. When it comes time to display the .ascx containing the Captcha control, the previous .ascx just sits there and nothing changes.
Admin > Event Viewer captures a Page Load Exception due to a "Object reference not set to an instance of an object.", with a lengthy stack trace. I include enough here to be suggestive:
System.NullReferenceException: Object reference not set to an instance of an object. at
DotNetNuke.UI.WebControls.CaptchaControl.Render(HtmlTextWriter writer) at
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at
System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at
System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at
System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at
System.Web.UI.Control.Render(HtmlTextWriter writer) at
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) at
System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) at
System.Web.UI.Control.RenderControl(HtmlTextWriter writer) at
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) at
System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) at
System.Web.UI.WebControls.WizardStepBase.RenderChildren(HtmlTextWriter writer) at
...
Why would the Captcha control have a problem rendering? What can I do about it?
TIA, Don Stuber