The data entered by the end user in various form fields must be validated before it is saved in the database. Developers often use validation HTML helpers provided by ASP.NET MVC to perform the input validations. Additionally, you can also use data annotation attributes from the System.ComponentModel.DataAnnotations namespace to perform validations at the model level. Data annotation attributes are attached to the properties of the model class and enforce some validation criteria. They are capable of performing validation on the server side as well as on the client side. This article discusses the basics of using these attributes in an ASP.NET MVC application.

http://www.bipinjoshi.net/articles/0a53f05f-b58c-47b1-a544-f032f5cfca58.aspx

A website is exposed to various types of attacks and one of the most common types of attack is what is known as Cross Site Scripting (XSS). In a cross site scripting attack, malicious markup and script is entered in the web pages that are viewed by other users. If proper care is not taken to filter this malicious piece of markup, the script gets stored in the system and also rendered on web pages. Depending on the script injected by the hacker it can cause damage ranging from annoying popups to stolen credentials to accessing data stored in cookies. Therefore, it is important for ASP.NET MVC developers to prevent these types of attacks. Luckily, ASP.NET MVC offers a helping hand in safeguarding your websites. This article discusses some of the basics involved in the process.

http://www.bipinjoshi.net/articles/7e79ca45-5bf7-4dc4-b97e-3fdbae06c988.aspx

Websites often need to generate SEO friendly URLs. In ASP.NET Web Forms applications, a URL is tied to a physical .aspx file. This default mapping between a URL and physical file makes it difficult for Web Forms applications to generate SEO friendly URLs. One option available to ASP.NET developers is to use URL routing features. Alternatively they can also use Friendly Urls - a feature that allows you to quickly and easily use SEO friendly URLs in Web Forms applications. This article discusses how.

http://www.bipinjoshi.net/articles/4fabc773-ffeb-4ac9-8b12-e39bb72b9ddc.aspx

Sometime back I wrote an article that shows how to zip and unzip files programmatically using System.IO.Compression classes. Using these classes along with ASP.NET controls you can allow user user to select one or more files from a list and then programmatically "bundle" these files into a ZIP archive. This short post shows how.

http://www.bipinjoshi.net/articles/2cd48325-5523-4442-98a8-63f12dba567b.aspx

Recently a reader asked about a tricky issue with HTML5 drag and drop. The issue is this:

HTML5 supports native drag and drop through draggable property and several events such as dragstart, drag, dragenter, dragleave, dragover and drop. Normally dragstart event handler is where you set the data that is to be transferred between the drag source and drop target. The drop event handler is where you handle the drop of a drag source, access the data transferred and process it further. Now, in this particular case only the dragstart and drop events were handled. And the drop event handler never used to get called. In other words dragging operation was successful but dropping operation was not.

http://www.bipinjoshi.net/articles/9ce78d52-7927-4fce-9dbc-d0d3f2bd6f70.aspx

For security reasons browsers prohibit AJAX calls to resources residing outside the current origin. This means you under the current settings, you can't provide a service exposed by a Web API to some other origin. However, at times you might want to allow a legitimate origin to access a resource. This is where Cross Origin Resource Sharing (CORS) specifications come into the picture. While there are other ways to enable CORS at the web application level, the ASP.NET Web API takes CORS support a step further through certain attributes. Using these attribute you can fine tune CORS at the global level, controller level or individual action level. This article discusses how this support can be used in your applications.

http://www.bipinjoshi.net/articles/540c368a-74ae-4693-a093-545e693988db.aspx

Most of us deal with Zip files on a daily basis. Normally people use some third-party utility to create, open and extract Zip files. At times you may want to deal with Zip files programmatically. Luckily, .NET framework 4.5 introduces some new classes in System.IO.Compression namespace that allows you to do just that. Using these classes you can create new Zip files, open and modify existing Zip files and extract the contents of Zip files via code. This article examines some of these classes.

http://www.bipinjoshi.net/articles/30c37391-0d15-4772-a9fc-822579fcdcc0.aspx

Basics of using arrays in C#:

Arrays are frequently used to store data of the same type. You can use arrays in C# in many different ways. Although single dimensional arrays are most commonly used, other varieties such as multidimensional arrays and jagged arrays are also available to C# developers. Additionally, the Array class comes in handy when it comes to sorting or searching an array. This article discusses all these types of arrays with examples of each.

http://www.bipinjoshi.net/articles/88bfd8e6-59d6-49fe-8a36-284d11707460.aspx

Whenever you access ASP.NET Web API from your client side script (JavaScript / jQuery) by default the data is returned in JSON format. However, in certain cases you lay want to retrieve the data in XML format instead of JSON. On the server side, Web API determinses what data format to use for sending data to the client by doing what is known as Content Negotiation. Simply put, content negotiation is a process by which Web API inspects the incoming request and HTTP headers accompanying the request to figure out what response format(s) the client can understand. Based on this checking Web API sends the output.

http://www.bipinjoshi.net/articles/6ef2100b-6561-4997-9df5-0864c5f23a21.aspx

C# preprocessor directives are commands that are meant for the C# compiler. Using preprocessor directives you instruct the C# compiler to alter the compilation process in some way. For example you may instruct the C# compiler that a particular block of code be excluded from the compilation process. This article examines several C# preprocessor directives available, with an example of each.

http://www.bipinjoshi.net/articles/fa0768e3-0db2-4fa8-af2a-e0dc92fec6d3.aspx