Twitter Bootstrap navigation with automatic active class for current page usng ASP.NET MVC

Posted on February 6, 2013 by Joe in ASP.NET, C#, MVC | Leave a comment

I’ve been playing around some more with Twitter Bootstrap and MVC and wanted to create a top level menu where the active class was added automatically to the item corresponding to the current page. Initially I had an action link inside the list item tag, but as the active class needs to be added to the list item so I decided to create an extension method to generate the entire item for me.

Optimistic Concurrency with MongoDB C# driver and ASP.NET MVC – Prevent multiple users updating the same record

Posted on January 31, 2013 by Joe in ASP.NET, C#, MongoDB, MVC | Leave a comment

Over on my MongoDB C# Tutorial Richard asked how you would prevent multiple users from updating the same document. In this post I’m going to update the project in the tutorial to support this.

In my blog example this issue could occur when user 1 clicks to edit a post. While editing, user 2 also edits the same post. User 2 finishes their edit before user 1 and saves the post. User 1 continues editing and saves their changes. User 2′s changes are completely overwritten and neither user has any idea that it happened.

In this implementation, based on the above scenario I’m going to display an error to user 2 to tell them somebody else has updated to the post. They won’t be able to save their changes and it would be up to them to reload the post and make their changes again. Of course you could do something much more exciting, like show the two versions side by side and allow the user to merge the changes.

Using KnockoutJS with SignalR in ASP.NET MVC

Posted on January 28, 2013 by Joe in ASP.NET, C#, MVC | Leave a comment

KnockoutJS is a MVVM implementation for JavaScript written by Steve Sanderson, in my opinion the author of the best ASP.NET MVC textbooks available. Simply put it lets you bind a JavaScript object model to your HTML UI using a simple binding format, and when the underlying model is updated the UI is automatically updated to reflect the change.

SignalR is a library from Microsoft utilising HTML5′s WebSockets allowing server side code to call JavaScript functions on the client to create real-time functionality.

To me these two libraries seem like a match made in heaven. SignalR calling a JavaScript function to alter data, and Knockout automatically updating the UI, awesome!

In this post I’ll show how you can use KnockoutJS and SignalR together to create real-time web application with little effort. I’m going to create a very basic example of a web page showing a list of exchange rates hooked up using KnockoutJS. I’ll then create a server side page to update the data and use SignalR to call a JavaScript function to update the JavaScript model.

Twitter Bootstrap validation styles with ASP.NET MVC

Posted on January 23, 2013 by Joe in ASP.NET, C#, jQuery, MVC | 2 Comments

Well it’s been a while since I’ve been blogging, two kids under 2 will do that to you. I’m going to try and get back into writing some regular posts.

Recently I’ve been playing around with Twitter Bootstrap, so the first thing I wanted to do was add it to an ASP.NET MVC 4 project. Getting the project set up was all pretty easy, and I quickly created a form using the horizontal form styles.

A MongoDB Tutorial using C# and ASP.NET MVC

Posted on October 2, 2011 by Joe in ASP.NET, C#, MongoDB, MVC | 30 Comments

In this post I’m going to create a simple ASP.NET MVC website for a simple blog that uses MongoDB and the offical 10gen C# driver.

MongoDB is no NOSQL database that stores information as Binary JSON (BSON) in documents. I have been working with it now for around 6 months on an enterprise application and so far am loving it. Our application is currently in alpha phase but should be public early next year! If you are used to working with an RDBMS, it takes a little bit of getting used to as generally you work with a denormalized schema. This means thinking about things quite differently to how you would previously; you’re going to have repeating data which is a no-no in a relational database, but it’s going to give you awesome performance, sure you may need an offline process that runs nightly and goes and cleans up your data, but for the real time performance gains it’s worth it.

ASP.NET MVC 2 client side validation for dynamic fields added with ajax

Posted on July 24, 2011 by Joe in Ajax, C#, MVC | 1 Comment

It’s quite common to add fields to a form dynamically using ajax, for example you may have a list of phone numbers for a user, and they could have many different phone numbers.

Using MVC you can easily add fields to a form by making an ajax call to an action that returns the rendered result of a partial view, but if you’ve tried doing this when using client side validation you’ll find the client side validation doesn’t work for those fields dynamically added to the form via the ajax call.

In this article I’ll explain a simple way to enable client side validation on those dynamically added fields.

Model Binding MongoDB ObjectId with ASP.NET MVC

Posted on June 12, 2011 by Joe in ASP.NET, C#, MongoDB, MVC | 10 Comments

If you’re using the MongoDB C# driver with ASP.NET MVC and have a property of type ObjectId in your model you will get the following error when trying to bind back to the model.

The parameter conversion from type ‘System.String’ to type ‘MongoDB.Bson.ObjectId’ failed because no type converter can convert between these types.

This can easily be resolved by creating a custom Model Binder which I’ll explain how to do in this article.

Creating strongly typed wrappers around untyped dictionaries in ASP.NET using the Castle DictionaryAdapter

Posted on June 9, 2011 by Joe in ASP.NET, C#, IoC, MVC | Leave a comment

Often when writing web applications you find yourself writing strongly typed wrapper classes around untyped dictionaries, such as Session, QueryString or even Web.Config Application Settings.

This is quite a tedious task, but using the Castle DictionaryAdapter this is all wrapped up nicely, and all you need to do is create an interface.

Editing and binding nested lists with ASP.NET MVC 2

Posted on June 6, 2011 by Joe in Ajax, ASP.NET, C#, JavaScript, jQuery, MVC | 14 Comments

Dynamically editing lists of data and binding back to the model with MVC is a little complicated as the id’s of the form elements need to all tie up for binding to succeed. Recently I had a model, which contained a list of an object, which in turn contained another nested list. Getting this to easily bind back to the model when adding to the lists dynamically was a bit of a headache so I’ll explain how I did it.

This article is inspired by this article by Steve Sanderson, but I also explain how to adapt it to bind nested lists.

ASP.NET MVC simple server-side ajax paging using jQuery

Posted on May 30, 2011 by Joe in Ajax, ASP.NET, C#, jQuery, MVC | 24 Comments

It’s always important to page your data on the server side so that you are only hitting the database to get the page you currently need, rather than getting all the results and paging on the client. In this post I’ll explain how to perform simple ajax paging on the server side using ASP.NET MVC 3.

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