Continue reading »]]> Recently I have been working on an MVC site using the Entity Framework. 

I have some related entities in my EF model, as show below in the form of “Reader” and “Category”, and the relationship between them, i.e. many to many.

When it came to proucing a view and action to perofrm the Create Reader action, I was somewhat puzzled as to how I could allow the user to select one or more categories for a reader. 

I started by having a view model that contained a list of all possible categories and then looping around these in my view and writing a check box out for each one.  When the form was submitted I looked through the form collection to find if any of the category check boxes had been selected.  I didn’t like this one bit and so I set out to find a cleaner way of carrying it out.

After some (quite a lot actually) searching, I stumbled accross the MultiSelectList type, which I could use in my ViewModel and then allow the default model binding to step in and do the leg work for me Great!

So, I created a view model, a simplified version of which you can see below;

    public class ReaderCreateViewModel : CustomViewModelBase
    {

        public ReaderCreateViewModel()
        {
            ReaderDetails = new Reader();
            CategoriesList = GetCategories(null);
        }

        public Reader ReaderDetails { get; set; }
        public MultiSelectList CategoriesList { get; private set; }
        public int[] SelectedCategories { get; set; }

        public MultiSelectList GetCategories(int[] selectedValues)
        {
            var te = new myEntities();
            List<Category> categories = te.Categories.ToList();
            return new MultiSelectList(categories, “id”, “Name”, selectedValues);
        }
    }

 As you can see from the code above, the view model contains my Reader entity, a list of type MultiSelectList, which is a list of available categories and an array of integers which represent the Id of any selected Categories.

Then to add a listbox to my view that will bind the MultiSelectList, I simply insert the following into my view.

            <p>
             <label for=”SelectedCategories”>Categories:</label>
        <%= Html.ListBox(“SelectedCategories”, Model.CategoriesList) %>
            </p>

Finally in my controller, I can simply check the SelectedItems object in my model for any selected Ids and add them to the Reader Categories list like this;

            if (model.SelectedCategories != null)
            {
                foreach (var selectedCat in model.SelectedCategories)
                {
                    int selectedCatId = selectedCat;
                    Category category = DataContext.Categories.Where(c => c.id                  == selectedCatId).FirstOrDefault();
                    reader.Categories.Add(category);
                }
            }

And that’s it.  Now there is probably a much better way of doing all or some of the above, but this worked perfectly for me when I needed it, so I hope it helps someone else out as well.  The final multi-select list box looked something like this;

Technorati Tags: ASP.NET MVC, Entity Framework, MVC

Continue reading »]]> If like me you are using ASP.NET MVC for some of your web applications these days and use MasterPages within them, then you may have come accross the need to pass ViewData to the MasterPage.  For example, this might be for a dynamically generated navigation bar.

When I first started using MVC, I simply passed the ViewData required for the MasterPage along with every action, but even with a small site, this was a lot of code replication.

To solve this problem, we can create an ApplicationController class which inherits from the Controller class we all know and love.  Your applications’ controllers then in turn simply inherit from this new ApplicationController.

Below is a simple example of an ApplicationController.

namespace MvcSite.Controllers
{
    public abstract class ApplicationController : Controller
    {
        private MyEntities _dataContext = new MyEntities();

        public MyEntities DataContext
        {
            get { return _dataContext; }
        }

        public ApplicationController()
        {
            ViewData["categories"] = DataContext.Categories.ToList();
        }

    }
}

Hope this helps someone else as well. Certainly removed a headache for me!

Technorati Tags: ASP.NET MVC

Continue reading »]]>

Scott Guthrie, Microsoft’s Corporate Vice Presedent and all round .Net Guru is coming to Manchester, UK, later this month to talk about what’s new with Visual Studio 2010, ASP.Net 4.0, Silverlight 3 and upcoming improvements to the MVC Framework!

Seating for this event, entitled Guathon 2009,  is very limited and as such you can only join the wait list at the moment, but I have been lucky enough to secure a place at what promises to be a fantastic workshop.

The announcement on the event home page over at DeveloperDeveloperDeveloper also has a funny section of “things you might not know about Scott Gu”, such as;

When Scott Guthrie throws exceptions, it’s across the room.

All arrays Scott Guthrie declares are of infinite size, because Scott Guthrie knows no bounds.

Scott Guthrie doesn’t have disk latency because the hard drive knows to hurry the hell up.

Scott Guthrie writes code that optimizes itself.

Scott Guthrie can’t test for equality because he has no equal.

Scott Guthrie doesn’t need garbage collection because he doesn’t call .Dispose(), he calls .DropKick().

For the rest of this amusing list and more info on the event or to add yourself to the wait list, visit the event home page.

Technorati Tags: ASP.Net, ASP.NET MVC, scott gu, scott guthrie, silverlight 3, visual studio 2010

Continue reading »]]> Title: ASP.NET MVC 1.0 Problem – Design – Solution

Publisher: Wrox

Authors: Nick Beradi, Al Katawazi, Marco Bellinaso

It seems that recently every man and his dog have been talking about ASP.Net MVC and the many advantages it brings along with it.  I have to admit that, up until now, I have not really looked into it a great deal, except for watching a couple of sessions at last years MSDN Roadshow.  Anyway, I decided that it was about time I found out more about ASP.Net MVC and see if it really was worth all of the hype.

Why did I read THIS book?

The reason I chose this book was two fold – firstly, it claimed to give you a good grounding in using ASP.Net MVC to those with experience of ASP.Net Web Development.  Secondly, in the books’ own words it provided “solid, workable solutions to real work problems” (I was dubious about this claim….many books I have read have claimed to do this and failed miserably with the first couple of chapters).

First Impressions

Right from the very first chapter it starts off on the correct foot, giving an overview of the application you will create as you work through the book, that application being The Beer House, which is available for download as a starter kit.  The main attraction of this application to me was that it contained many of the features I often implement in my own applications, such as forums, article management and user profile / membership management.  The idea of reading a book that directly relates to my real-world programming was a big pull for me.

Thankfully, this book certainly does not try and force MVC down your throat as a must-use solution, instead giving an honest opinion that, yes MVC is very useful in many situations, but that in other situations, classic ASP.Net Web Forms may still be the more logical option.  This is a refreshing change from some of the other more self-righteous books I have had the des-pleasure of sampling where they simply see their subject matter and related methods as the only way to go.

What’s Covered?

I don’t think I can put the content of the book in better words that the book itself, so here are those very words;

All of the above is covered in ample detail and I really did find this book extremely useful when relating the MVC implementation with my tradition Web Forms methods.

I especially liked the fact that attention was paid to the design of the application you create.  Coming from a web design background I am often astounded by the lack of attention paid to this area and it was pleasing to see a chapter dedicated to this for the non-design minded developer.

The other thing I loved about this book was that as well as ensuring every detail was covered off when developing each solution for the Beer House application, the authors have made a clear effort to highlight when something more may be needed in different circumstances and provided sample code and examples where needed.

Source Code Problems

Probably the only bad thing I have to say about this book were the problems I had when attempting to get the source code to compile once I had downloaded it from the Wrox web site.  I think the main problem was that the code on the site was possibly an old version with several other versions kicking around the internet.  I am unsure as to which was the correct up-to-date copy.

However, all that said, with some tinkering, I did manage to get it to compile and what a lovely application it is.

The Final Verdict

I found this book to be an extremely concise and focused journey through ASP.Net MVC and a perfect introduction to the subject and I would highly recommend it to anybody who is looking for a good grounding in the subject.

This was also my first read of a book from the Problem – Design – Solution series from Wrox, and if the other books in the series are in a similar style, then I look forward to reading more as the straight forward style with real-world connections suited me down to the ground.  

You can find this book for sale on Amazon or from the Wiley web site.

Technorati Tags: ASP.Net, ASP.NET MVC, book review, C#, wrox

Continue reading »]]> Ok, so a few weeks ago I posted about my plans to attend the MSDN Roadshow 2008 in Manchester and I said that I would post about the event once I had attended.  So as promised here is that very post along with some useful links;

Firstly, the venue for this years event was excellent.  The Odeon in Manchester City Centre in the Printworks is quite simply huge.  Luckily there were escalators for those of use who were to lazy to climb all of the stairs.

Once you reached the third floor, we were greeted by poster boxes with MSDN posters inside with some nice quotes, such as "There’s No Place Like 127.0.0.1" and "I’ll make him a program he can’t refuse", which was a nice touch I thought. Made the whole thing feel like more of an event rather than just a meeting.

In the corridor outside of the actual conference room were the usual stands familiar to those who have attended a Roadshow before, such as the registration table, a stand with discount books from the guys over at Computer Manuals selling discounted books on a variety of subjects from Expression to LINQ and of course, every developers favourite stand, the SWAG stand, with free goodies like the updated Developers Highway Code (which is available for download and I have included a link in the useful links later in this post).  We did all get a free software pack when we left, but more on that shortly.

In addition to the usual stands this year though, we were treated to a couple of really interesting tables showing off the XNA Framework on a dev Xbox 360 and the new Microsoft Robotics studio.  I have to say, some of the games produced with the XNA framework for the 360 were pretty impressive and most of them are available as starter kits from Microsoft if you’re interested.  I will include some links for both of these areas at the end of this post.

The conference room itself was actually a cinema room (surprisingly being at the Odeon ), which was fantastic.  This meant most people got comfortable seats to enjoy the show and those all important cup holders! I arrived slightly late, and so didn’t manage to get a seat, however, the nice Roadshow staff got me a seat and put me right at the side of the stage and I got a ringside seat which was great.  As you can see from the picture to the right (apologies for the quality, somehow I managed to set my camera phones’ resolution unusually low by mistake) of MSDNs Mike Ormond presenting, the slide being on a cinema screen really helped, as they were always clear and nobody was struggling to see anything.

The presentations themselves were, as always, of an excellent quality, with the speakers conveying their expert knowledge in their respective topics clearly and concisely.  I particularly enjoyed Mike Ormonds’ talk on the ASP.NET 3.5 Extensions, especially the new Dynamic Data capabilities (which I am hopefully going to be posting a small tutorial series about shortly. If you’re interested, add this blog to you’re favourites or subscribe to my RSS Feed).

The refreshments this year were good, a choice between ham, cheese and chicken sandwiches, along with crisps and soft drinks for lunch.  Very nice Coffee during the breaks and even popcorn or Ben and Jerrys ice cream in the afternoon!

As I have already mentioned, if you handed in your feedback form and your pass before you left you were treated to a nice software pack, which didn’t disappoint.  Contained within the set were promotional copies of Windows Server 2008 32bit and 64bit editions, SQL Server 2008 Preview along with a voucher to get a development copy when it is released, and my personal favourite, a full copy of Visual Studio 2008.

All in all, an excellent day, well put together and very well received!

One last note, the MSDN Roadshow’s are an invaluable free event from Microsoft giving excellent technical and hands-on insight into the latest techniques and strategies for developers.  Every year they seem to sell out really fast, so my one message to you for next year is….REGISTER EARLY!

Now as promised, some useful links regarding the days speakers, events and topics;

Presentation Slides

Definitely worth a look through…..

Xbox 360 XNA Game Framework and Microsoft Robotics Studio and the Developer Highway Code

As promised, a couple of links to the areas that were the subject of two impressive stands this years event.

Technorati Tags: .net 3.5, ADO.NET, ASP.NET MVC, Dynamic Data, Microsoft Robotics, MSDN, Silverlight, XNA Framework