Hi, I created a custom captch fieldtype using MSCaptcha. The custom control seems to be working fine in a normal .aspx page, but it's not working when it's within contour form page. I added a custom validator to validate the captcha text, the validation works fine but the form is not submitting even though the page is valid. I wonder if there's anything wrong my fieldtype? Any help would be appreciated. Thanks.

Here is the code for my custom captcha control:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.UI;
using System.Web.UI.WebControls;
using MSCaptcha;

namespace Model.Forms.Controls
{
    public class Captcha : TextBox
    {
        public CaptchaControl CaptchaControl
        {
            get
            {
                EnsureChildControls();
                return this.captcha;
            }
            set
            {
                this.captcha = value;
            }
        }

        private CaptchaControl captcha;
        private CustomValidator captchaVal;

        protected override void OnInit(EventArgs e)
        {
            string vGroup = string.Empty;
            List<RequiredFieldValidator> reqValidators = this.ControlsByTypeUsingAncestor<RequiredFieldValidator>(this.Page);

            if (reqValidators != null)
            {
                var validatorWithGroupSet = (from v in reqValidators
                                             where v.ValidationGroup != string.Empty
                                             select v);

                if (validatorWithGroupSet != null)
                    vGroup = validatorWithGroupSet.FirstOrDefault().ValidationGroup;
            }

            this.captcha = new CaptchaControl();
            this.captcha.CaptchaBackgroundNoise = CaptchaImage.backgroundNoiseLevel.Low;
            this.captcha.NoiseColor = System.Drawing.Color.FromArgb(251, 194, 196);
            this.captcha.CaptchaLength = 4;
            this.captcha.CaptchaHeight = 60;
            this.captcha.CaptchaWidth = 250;
            this.captcha.CaptchaLineNoise = CaptchaImage.lineNoiseLevel.None;
            this.captcha.CaptchaMinTimeout = 5;
            this.captcha.CaptchaMaxTimeout = 240;

            base.CssClass = "text";

            this.captchaVal = new CustomValidator();
            this.captchaVal.ErrorMessage = "Invalid code";
            this.captchaVal.ServerValidate += new ServerValidateEventHandler(captchaVal_ServerValidate);
            this.captchaVal.IsValid = true;
            this.captchaVal.Display = ValidatorDisplay.Dynamic;
            this.captchaVal.ValidateEmptyText = true;
            this.captchaVal.EnableClientScript = false;
            this.captchaVal.CssClass = "contourError";

            if (!string.IsNullOrEmpty(vGroup))
            {
                base.ValidationGroup = vGroup;
                this.captchaVal.ValidationGroup = vGroup;
            }

            base.Controls.Add(this.captchaVal);
            base.Controls.Add(this.captcha);
        }

        void captchaVal_ServerValidate(object source, ServerValidateEventArgs args)
        {
            try
            {
                args.IsValid = ValidateCaptcha();
            }
            catch
            {
                args.IsValid = false;
            }
        }

        private bool ValidateCaptcha()
        {
            bool flag = true;

            if (this.captcha != null)
            {
                if (string.IsNullOrEmpty(base.Text))
                {
                    flag = false;
                }
                else
                {
                    this.captcha.ValidateCaptcha(base.Text);
                    flag = this.captcha.UserValidated;
                }
            }
            else
            {
                flag = false;
            }

            if (flag)
                this.captchaVal.Style.Add("display", "none");
            else
                this.captchaVal.Style.Add("display", "block");

            return flag;
        }

        protected override void Render(HtmlTextWriter writer)
        {
            base.RenderChildren(writer);
            base.Render(writer);           
        }

        /// <summary>
        /// get find control method using generics
        /// </summary>
        /// <typeparam name="T">type of item you want</typeparam>
        /// <param name="ancestor">parent to start looking from</param>
        /// <returns>collection of T items</returns>
        public List<T> ControlsByTypeUsingAncestor<T>(Control ancestor) where T : Control
        {
            var controls = new List<T>();

            //Append to search results if we match the type
            if (typeof(T).IsAssignableFrom(ancestor.GetType()))
            {
                controls.Add((T)ancestor);
            }

            //Recurse into child controls
            foreach (Control ctrl in ancestor.Controls)
            {
                controls.AddRange(ControlsByTypeUsingAncestor<T>(ctrl));
            }

            return controls;
        }
    }
}

And my custom field type:

using System;
using System.Collections.Generic;
using System.Web.UI.WebControls;
using Umbraco.Forms.Core;

namespace Model.Forms.FieldTypes
{
    public class Captcha : FieldType
    {
        public Controls.Captcha CaptchaControl;

        public List<object> Value;

        public Captcha()
        {
            base.Id = new Guid("F8C089B9-7D8F-47B0-A594-9FD9903FBF42");
            base.Name = "Captcha";
            base.Description = "Renders a Captcha";
            this.Icon = "textfield.png";
            this.DataType = FieldDataType.String;
            this.Value = new List<object>();

            this.CaptchaControl = new Controls.Captcha();
        }

        public override WebControl Editor
        {
            get
            {
                return this.CaptchaControl;
            }
            set
            {
                base.Editor = value;
            }
        }

        public override List<object> Values
        {
            get
            {
                if (!string.IsNullOrEmpty(this.CaptchaControl.Text))
                {
                    this.Value.Clear();
                    this.Value.Add(this.CaptchaControl.Text);
                }
                return this.Value;
            }
            set
            {
                this.Value = value;
            }
        }

        public override bool SupportsPrevalues
        {
            get
            {
                return false;
            }
        }

        public override bool SupportsRegex
        {
            get
            {
                return false;
            }
        }

        public override string RenderPreview()
        {
            return "<img src=\"/Images/layout/capex.jpg\" alt=\"captcha\" /><br /><input type=\"text\" class=\"textfield\" />";
        }

        public override string RenderPreviewWithPrevalues(List<object> prevalues)
        {
            return this.RenderPreview();
        }
    }
}