Validate Custom Image FieldTemplate

I've created a custom Image Field Template which works fine. I decided to create some kind of validation for image sizes so I've created a custom validation attribute. here is the code:

public class ImageSizeValidator : ValidationAttribute
    {
        public long MaxSize { get; set; }
        public long MinSize { get; set; }

        public override bool IsValid(object value)
        {
            if (value == null)
                return true;

            byte[] image = (byte[]) value;

            if (image.Length / 1024L > MaxSize || image.Length / 1024L < MinSize)
                return false;

            return true;
        }
    }

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="Image_Edit.ascx.cs" Inherits="RastinArgham.CRM.Web.DynamicData.FieldTemplates.Image_Edit" %>

<asp:FileUpload ID="FileUpload1" runat="server" OnDataBinding="FileUpload1DataBinding" />

<asp:RequiredFieldValidator runat="server" ID="RequiredFieldValidator1" CssClass="DDControl DDValidator" ControlToValidate="FileUpload1" Display="Static" Enabled="false" />
<asp:DynamicValidator runat="server" ID="DynamicValidator1" CssClass="DDControl DDValidator" ControlToValidate="FileUpload1" Display="Static" />

public partial class Image_Edit : System.Web.DynamicData.FieldTemplateUserControl
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            SetUpValidator(RequiredFieldValidator1);
            SetUpValidator(DynamicValidator1);
        }

        protected override void ExtractValues(IOrderedDictionary dictionary)
        {
            if (FileUpload1.PostedFile == null || String.IsNullOrEmpty(FileUpload1.PostedFile.FileName) || FileUpload1.PostedFile.InputStream.Length == 0)
                return;

            dictionary[Column.Name] = FileUpload1.FileBytes;
        }

        public override Control DataControl
        {
            get
            {
                return FileUpload1;
            }
        }
    }

There are two problems:
1- when IsValid(object value) called value is always null!
2- when trying to upload a new image I always get "The value is not valid" Error on client side of validation.

by the way here is my entity metadata code:

[Display(Name = "ServicePhoto", Order = 410, GroupName = "Misc")]
[HideColumnIn(PageTemplate.List)]
[UIHint("Image")]
[ImageSizeValidator(ErrorMessage = "Invalid Photo Size", MinSize = 30, MaxSize = 300)]
public object ServicePhoto { get; set; }

Re: Validate Custom Image FieldTemplate

Hello

In my mindsides checking the value is null or notyou should save the file posted onto the server and then show it

The reason why your object is always null is that the file won't be submitted until you click a submit button or something like this

Please debug your app and check whether your FileBytes is null or notAnd check whether the column.Name is fitable or notmy suggestionn is that you can use a fixed string instead of the column.Name instead

Regurads