Tanzim Saqib on .NET discovery

DropZone: How I built a database-less secured file storage using dotnetopenid

Tanzim Saqib — Sat, 27 Jun 2009 03:13:27 PDT

One of my friends work for a company where he has to work in a remote PC and where he lives he does not have good internet connection. He neither has permission for opening up third party email website such GMail, nor he could download email with 100MBs...(read more)

Success story from Microsoft Day @ Dhaka

Tanzim Saqib — Wed, 24 Jun 2009 08:05:57 PDT

As you probably know from the earlier posts or you might have attended already Microsoft Day , I spoke on Development in ASP.NET [WebForms, LINQ, Dynamic Data, Futures] on June 20th. Some of the enthusiasts still communicating with me even after the Microsoft...(read more)

Presentation at Microsoft Day @ Dhaka

Tanzim Saqib — Sun, 21 Jun 2009 09:27:46 PDT

As I have told earlier about the Microsoft Day @ Dhaka event , and as I have promised, this post is about the presentation slide the audience was asking for. I am so glad to receive appreciation about the session and overall event. I am really happy the...(read more)

I will be speaking at Microsoft Day @ Dhaka

Tanzim Saqib — Thu, 18 Jun 2009 10:58:40 PDT

Microsoft Community in Bangladesh proudly presents Microsoft Day @ Dhaka. This is a special day dedicated to all Microsoft technology professionals and students in Bangladesh. We will be having the best Microsoft community technologists from Bangladesh...(read more)

ASP.NET MVC 1.0 Starter Kit for Visual Studio 2010

Tanzim Saqib — Tue, 26 May 2009 06:47:14 PDT

I have described before in my prior post how you can run your ASP.NET MVC application in Visual Studio 2010. There is currently no support for ASP.NET MVC project types in Visual Studio 2010 Beta 1. So what I did is I created a starter kit for ASP.NET...(read more)

Running a ASP.NET MVC project on Visual Studio 2010 Beta1

Tanzim Saqib — Sat, 23 May 2009 21:37:57 PDT

You probably already know that ASP.NET MVC is not included with Visual Studio 2010 Beta1 since MVC was released when Visual Studio release was being locked down. I hope it will be available from Beta2. It also looks like if you install ASP.NET MVC after...(read more)

Building a basic Menu control for ASP.NET MVC

Tanzim Saqib — Sat, 23 May 2009 11:23:47 PDT

There are two different ways to build controls for ASP.NET MVC as of now. The most common way is by HTML Helper extension methods. You will find such methods being used in numerous places inside Views. Such methods can take any complexity of parameters...(read more)

CallQueue: Implementing a Sequential Web Service Call Queue for AJAX application

Tanzim Saqib — Wed, 19 Nov 2008 02:12:36 PST

In AJAX based applications its common that user might end up breaking your AJAX calls by clicking on numerous places in very short interval of time. Let us assume there is a page where there are several of hyperlinks which make WebService calls and do...(read more)

My eye friendly Visual Studio dark theme

Tanzim Saqib — Mon, 17 Nov 2008 20:11:07 PST

I am not sure about how you guys feel about your IDE look & feel. First few years it was alright for me. However the more I used Visual Studio, the more I experienced problem with my eyes as well as monotony of the same old white background IDE. So...(read more)

Client Perspective of Windows Azure Services Platform

Tanzim Saqib — Fri, 14 Nov 2008 03:11:16 PST

Windows Azure was announced on PDC 2008 (Oct 27) and will hopefully be released mid next year. You probably already know about Azure by this time. If no, I would like to quote some from www.azure.com as intro: The Azure Services Platform is an internet...(read more)

Cloudship: Membership Provider for the Cloud

Tanzim Saqib — Thu, 13 Nov 2008 21:09:30 PST

Planning to move to the Azure Cloud, but already tied to the Membership API? I have recently written an article on Windows Azure which guides you to build a complete Membership provider library which can be leveraged by existing application to link to...(read more)

Building applications for Windows Azure

Tanzim Saqib — Fri, 07 Nov 2008 01:12:18 PST

Windows Azure is an upcoming operating system for the cloud from Microsoft, announced on October 27 at PDC. Windows Azure provides developers with on-demand compute and storage to host, scale, and manage Web applications on the Internet through Microsoft...(read more)

Fixing DevelopmentStorage's database cannot be found problem on Windows Azure

Tanzim Saqib — Fri, 31 Oct 2008 11:00:13 PDT

This could be a common problem who are not using SQL Express. If you run an Azure application you may find it seeks for SQL Express instance in your machine if you do not have already. You may also find "An error occurred while processing this request...(read more)

jQuery intellisense in Visual Studio

Tanzim Saqib — Mon, 27 Oct 2008 20:20:43 PDT

Those who are excited like me about the news of jQuery integration into Visual Studio, started adopting jQuery replacing ASP.NET AJAX Client side API. Microsoft also declared there will be a patch for Visual Studio which will support jQuery as well as...(read more)

Simple Form Validation - A Reflection based approach

Tanzim Saqib — Fri, 28 Mar 2008 09:02:24 PDT

Are you tired of placing multiple Validation controls on Form? If you are bored of following scenario like me, keep on reading the post:

A simple Email address validation can consist of whether

The field is empty
Longer than limit
Email address format is invalid
Already in use

Ordinary solution to this problem is placing multiple validation controls for a single TextBox. You can simply it by replacing all with a single Custom Validator. Our goal is to reduce amount of controls on the form to keep it simple. To do that, we would have to write code for Custom Validator that does it all. We also would like to write minimum code to validate the control without compromising manageability. Let us assume we would write the following code inside the ServerValidate of that control:

protected void cvEmailAddress_ServerValidate(object source, ServerValidateEventArgs args)
{
    ValidationController.ValidateControl<ProfileValidator>(cvEmailAddress, ProfileValidator.Fields.EmailAddress.ToString(), args);
}

Let us declare a ValidationErrorResult object that contains error messages and text to display in the UI:

public sealed class ValidationErrorResult
{
    public string ErrorMessage { get; set; }
    public string Text { get; set; }
}

And an Attribute which would be used to tag a specific method which would be responsible for validation of particular control:

[AttributeUsage(AttributeTargets.Method, Inherited = false, AllowMultiple = true)]
public sealed class ValidationMethodAttribute : Attribute
{
    public ValidationMethodAttribute(string fieldName)
    {
        this.FieldName = fieldName;
    }

    public string FieldName { get; private set; }
}

If you are already familiar with Attirbute based programming, I hope you know the attribute of this piece of code is in fact ValidationMethod. We will soon see how to use this. The following is the method that checks the value and make a list of ValidationErrorResult that consists of which rules got failed. Notice that the ValidationMethod attribute contains the field name of the object which determines no matter whatever your method name is, that field name helps Validation controller to find this method out for validation.

[ValidationMethod("Email")]
public static List<ValidationErrorResult> ValidateEmail(object value)
{
    var email = value as string;
    var results = new List<ValidationErrorResult>();

    // Blank
    if (string.IsNullOrEmpty(email))
        results.Add(new ValidationErrorResult()
        {
            ErrorMessage = "You did not provide an Email Address.",
            Text = "Cannot be left blank"
        });

    // Length 128
    if (email.Length > 128)
        results.Add(new ValidationErrorResult()
        {
            ErrorMessage = "You exceeded length limit.",
            Text = "Keep it less than 129 characters"
        });

    // Valid Email Address
    if (!Regex.IsMatch(email, "^[\\w\\.\\-]+@[a-zA-Z0-9\\-]+(\\.[a-zA-Z0-9\\-]{1,})*(\\.[a-zA-Z]{2,3}){1,2}$"))
        results.Add(new ValidationErrorResult()
        {
            ErrorMessage = "You provided an invalid Email Address.",
            Text = "Invalid Email Address"
        });

    // Is Already In Use
    if (IsAlreadyInUse(email))
        results.Add(new ValidationErrorResult()
        {
            ErrorMessage = "You provided an invalid Email Address.",
            Text = "Invalid Email Address"
        });

    return results;
}

Here is the ValidationController which goes through the Validation class and looks for the method that has the attribute which validates the control's value.

public class ValidationController
{
    public static List<ValidationErrorResult> Validate<T>(string fieldName, object value)
    {
        var results = new List<ValidationErrorResult>();
        var type = typeof(T);
        var methods = type.GetMethods(BindingFlags.Static | BindingFlags.Public);

        var method = methods.Single<MethodInfo>(delegate(MethodInfo m)
        {
            return ((ValidationMethodAttribute[])m.GetCustomAttributes(typeof(ValidationMethodAttribute), false))[0].FieldName == fieldName;
        });

        return (List<ValidationErrorResult>)method.Invoke(null, new object[] { value });
    }

    public static void ValidateControl<T>(CustomValidator validator, string fieldName, ServerValidateEventArgs args)
    {
        var results = Validate<T>(fieldName, args.Value);

        if (!(args.IsValid = !(results.Count > 0)))
        {
            validator.ErrorMessage = results[0].ErrorMessage;
            validator.Text = results[0].Text;
        }
    }
}