protected void IsAvailablePass(object source, ServerValidateEventArgs args)
        {
            var hashre = new PasswordHasher();

            args.IsValid = (hashre.VerifyHashedPassword(Context.User.Identity.GetUserInfo().PasswordHash, args.Value)) ==
                           PasswordVerificationResult.Success;
        }

 protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
 {
     if (CheckBoxRegulamin.Checked)
         args.IsValid = true;
     else
         args.IsValid = false;
 }

 protected void CustomValidator4_ServerValidate(object source, ServerValidateEventArgs args)
 {
     if (CheckBox1.Checked && TextBox1.Text == "")
     {
         args.IsValid = false;
     }
 }

 public void val_email(object source, ServerValidateEventArgs args)
 {
     Regex rgxEmail = new Regex(@"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" +
                    @"\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" +
                    @".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$");
     args.IsValid = rgxEmail.IsMatch(args.Value);
 }

        private void ValidateImage(object source, ServerValidateEventArgs args)
        {
            if (FileUploadEdit.HasFile)
            {
                var bytes = FileUploadEdit.FileBytes;

                try
                {
                    var image = System.Drawing.Image.FromStream(new MemoryStream(bytes));
                }
                catch
                {
                    // catch any error when user tries to load a file that 
                    // is not an image recognised by System.Drawing
                    args.IsValid = false;
                    CustomValidator1.ErrorMessage = "Not an Image";
                }
            }
            else
            {
                return;
                // no file to download you decide wether this is a valid error
                // to throw comment out
                if (!FileUploadEdit.HasFile && String.IsNullOrEmpty(ImageEdit.ImageUrl))
                {
                    args.IsValid = false;
                    CustomValidator1.ErrorMessage = "No file to download";
                }
            }
        }

 protected void CvUserName_ServerValidate(object source, ServerValidateEventArgs args)
 {
     if (args.Value.Length >= 6)
         args.IsValid = true;
     else
         args.IsValid = false;
 }

 protected void cvProcName_ServerValidate(object source, ServerValidateEventArgs args)
 {
     //默认不存在该部门
     args.IsValid = false;
     //检测是否存在部门
     args.IsValid = ydPublicMethod.IsExistProc(args.Value);
 }

 protected void CheckDate(object sender, ServerValidateEventArgs e)
 {
     DateTime date;
     bool IsDate = DateTime.TryParse(e.Value, out date);
     if (IsDate) e.IsValid = true;
     else e.IsValid = false;
 }

 protected void CheckPassword(object source, ServerValidateEventArgs args)
 {
     if (WebClient.RevalidatePassword(PasswordField.Text))
         args.IsValid = true;
     else
         args.IsValid = false;
 }

 protected void cvTitle_ServerValidate(object source, ServerValidateEventArgs args)
 {
     SqlDataAdapter da = new SqlDataAdapter("", connection);
     DataTable dt = new DataTable();
     DataTable dl = new DataTable();
     da.SelectCommand.CommandText = "SELECT * FROM Skills WHERE ID = @sxid";
     da.SelectCommand.Parameters.AddWithValue("@sxid", Request.QueryString["Sid"]);
     da.Fill(dl);
     //Consept : Check if TextBox' value has changed or not
     //If This part doesn't Exist -> the page won't be valid Because of the next part of Validation. WHY? ...
     //if the title isn't changed the next part cause invalidation beacuse the Title has already Exist
     if (dl.Rows[0]["Title"].ToString() != txtTitle.Text)
     {
         da.SelectCommand.CommandText = "SELECT * FROM Skills WHERE [email protected] AND [email protected]";
         da.SelectCommand.Parameters.AddWithValue("@t", txtTitle.Text);
         da.SelectCommand.Parameters.AddWithValue("@scid", ddlSkillCat.SelectedValue);
         da.Fill(dt);
         //If the TextBox' Value has changed ...
         //So , Now Check if The New Value has already Exist in Table or not
         if (dt.Rows.Count == 0)
         {
             args.IsValid = true;
         }
         else
             args.IsValid = false;
     }
 }

        protected void cvCaptcha_ServerValidate(object source, ServerValidateEventArgs args)
        {
            bool isValid = false;

            if (ViewState["captchaToken"] != null)
            {
                Guid captchaToken = (Guid)ViewState["captchaToken"];
                using (CSSDataContext db = new CSSDataContext())
                {
                    var captcha = db.Captchas.FirstOrDefault(p => p.Id == captchaToken);

                    //args.Value
                    //CustomValidator cvCaptcha = (CustomValidator)source;
                    //TextBox txtValidationCode = (TextBox) cvCaptcha.ControlToValidate;
                    if (captcha != null && args.Value.Equals(captcha.Answer, StringComparison.InvariantCultureIgnoreCase) == true)
                    {
                        isValid = true;
                    }
                }
            }

            if (isValid == false)
                ViewState["captchaToken"] = null;

            args.IsValid = isValid;
        }

 protected void IsAvailableEmail(object source, ServerValidateEventArgs args)
 {
     using (_repository)
     {
         args.IsValid = !_repository.Users.Select(s => s.Email).Contains(this.EmailTexbox.Text);
     }
 }

 protected void LogoValidator_ServerValidate(object sender, ServerValidateEventArgs e)
 {
     if (e.Value.Length > 0)
     {
         e.IsValid = FileType.IsImageFile(e.Value);
     }
 }

        protected void CustomValidator_ServerValidate(object source, ServerValidateEventArgs args)
        {
            //string imageName = Guid.NewGuid().ToString().Substring(0, 8);
            //string geocacheImageTemp = imageName + ".bmp";
            //System.Drawing.Bitmap bmpPostedImage = new System.Drawing.Bitmap(imageFileUpload.PostedFile.InputStream);
            //bmpPostedImage.Save(Server.MapPath(@"temp\") + imageName + ".bmp");
            ////bmpPostedImage.Save("C:\\Users\\Juliana\\Documents\\GitHub\\ASECPJ\\ASECPJ\\geocache\\temp\\" + imageName + ".bmp");

            //Stegano decryptStegano = new Stegano();
            //string message = decryptStegano.RetrieveMessage(Server.MapPath(@"temp\") + imageName + ".bmp");
            ////string message = decryptStegano.RetrieveMessage("C:\\Users\\Juliana\\Documents\\GitHub\\ASECPJ\\ASECPJ\\geocache\\temp\\3a902149.bmp");

            //if (message.Equals(""))
            //{
            //    Response.Redirect("true");
            //    args.IsValid = true;

            //}
            //else
            //{
            //    Response.Redirect("false");
            //    args.IsValid = false;
            //}

            args.IsValid = true;
        }

 protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
 {
     if (Image1.ImageUrl == "Images/icon_visa.png")
     {
         if ((txtCard.Text).Count() == 16 || (txtCard.Text).Count() == 13)
             args.IsValid = true;
         else
             args.IsValid = false;
     }
     else
         if (Image1.ImageUrl =="Images/apps_mastercard.png")
         {
             if ((txtCard.Text).Count() == 16)
                 args.IsValid = true;
             else
                 args.IsValid = false;
         }
         else
             if (Image1.ImageUrl =="Images/download.jpg")
             {
                 if ((txtCard.Text).Count() == 15)
                     args.IsValid = true;
                 else
                     args.IsValid = false;
             }
             else args.IsValid = false;
 }

        protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
        {
            try
            {
                var connString = ConfigurationManager.ConnectionStrings["CineQuilla"].ConnectionString;
                using (SqlConnection connection = new SqlConnection(connString))
                {
                    connection.Open();
                    using (SqlCommand command = new SqlCommand(null, connection))
                    {
                        command.CommandText = @"SELECT 1 FROM clients WHERE id = @id";
                        SqlParameter idParam = new SqlParameter("@id", SqlDbType.Int);

                        idParam.Value = args.Value;

                        command.Parameters.Add(idParam);

                        var reader = command.ExecuteReader();
                        if (!reader.HasRows)
                            args.IsValid = false;
                    }
                }
            }
            catch (SqlException ex)
            {
                ErrorLabel.Visible = true;
                args.IsValid = false;
            }
        }

 protected void validateFile(object sender, ServerValidateEventArgs e)
 {
     if(Path.GetExtension(e.Value) == ".jpg" || Path.GetExtension(e.Value) == ".png" || Path.GetExtension(e.Value) == ".gif")
         e.IsValid = true;
     else
         e.IsValid = false;
 }

 //Validate input service group name
 //Add Option - Validate existence of group naem
 protected void ExistenceCustomValidator_ServerValidate(object source, ServerValidateEventArgs args)
 {
     var inputValue = args.Value.ToString();
     var icdChapters = from element in _dataContext.IcdChapters
                        select element.icdChapterName.ToString().ToLower();
     foreach (var chapter in icdChapters.ToArray())
     {
         if (chapter.ToString().ToLower().Equals(inputValue.ToLower()))
         {
             args.IsValid = true;
             return;
         }
     }
     args.IsValid = false;
     //int editIndex = MedicalServiceList.EditIndex;
     //TextBox textBox = MedicalServiceList.Rows[editIndex].FindControl("EditGroupId") as TextBox;
     //var inputStringData = textBox.Text;
     //var inputIntData = Convert.ToInt64(inputStringData);
     //var idList = from element in _dataContext.MedicalServiceGroups
     //             select element.medicalServiceGroupId;
     //foreach (var id in idList.ToArray())
     //{
     //    if (id == inputIntData)
     //    {
     //        args.IsValid = true;
     //        return;
     //    }
     //}
     //args.IsValid = false;
 }

 protected void cvIsActive_ServerValidate(object source, ServerValidateEventArgs args)
 {
     if (chkDone.Checked != true)
         args.IsValid = false;
     else
         args.IsValid = true;
 }

 protected void Automobile_ServerValidate(object sender, ServerValidateEventArgs e)
 {
     int automobileId;
     string automobileIdTxt = e.Value;
     bool validAutomobile = Int32.TryParse(automobileIdTxt, out automobileId) && (automobileId >= 0);
     e.IsValid = validAutomobile;
 }