The Problem Solver : ASP.NET

CodeCamp jQTouch session

Maurice — Sat, 21 Nov 2009 18:05:01 GMT

If you are looking for the demo files from my CodeCamp presentation in the Netherlands you can download the notes here and the complete sample code here. No PowerPoint, after all this was a CodeCamp

And when my ISP is fully operational again the demo can be viewed online here.

Enjoy, I enjoyed organizing the CodeCamp and doing this presentation.

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

Nederlandse CodeCamp 2009

Maurice — Mon, 19 Oct 2009 10:26:00 GMT

Op 21 november 2009 organiseren de SDN, Stichting dotNed en VBcentral samen het derde Nederlandse Code Camp. Dit is een dag lang met code, code sharing, freaking en gezellig samenzijn. Een evenement door ontwikkelaars, voor ontwikkelaars. De regie ligt voor een belangrijk deel bij de deelnemers! Het aantal plaatsen voor deelnemers is wel beperkt tot maximaal 150. Wacht dus niet te lang met beslissen want voor je het weet is er geen plaats meer. Vergeet bij je aanmelding niet op te geven welke onderwerpen je interesse hebben. Bovendien nodigen we iedereen graag uit om zelf een sessie in te vullen.

Op de website, www.codecamp.nl, vind je meer informatie en kan je je aanmelden.

Combined DevelopMentor instructors blog feed.

Maurice — Wed, 19 Aug 2009 07:37:12 GMT

Michael Kennedy, one of the co instructors from DevelopMentor, has created a combined feed from all the blogs of the various DevelopMentor. An awesome group of people with a lot of knowledge to share. Highly recommended in you RSS reader.

http://feeds.feedburner.com/DevelopmentorInstructors

If you want to check out a list of the individual blog feeds look here.

Enjoy!

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

Using ASP.NET MVC

Maurice — Thu, 13 Aug 2009 17:26:44 GMT

Recently I started using ASP.NET MVC for a real project. SO far I had been reluctant to use ASP.NET MVC as it meant giving up on the post back model that so many of the available ASP.NET controls depend on. Yet a lot of people I know and respect where saying good things about ASP.NET MVC so I decided to try it out on a small but real project.

Well the project isn’t finished yet but I am a convert

Using ASP.NET MVC is much nicer that I expected it to be. Sure the post back model, and with it a lot of controls, are gone but I started doing more client side stuff using jQuery and the many plug-ins available. And even where not doing a lot of client side work ASP.NET MVC makes live quite easy.

The main difference is that ASP.NET MVC lends itself very well to test driven development. Now I not a pure TDD zealot but covering a lot of the code with unit test, regardless if you create the test first or later, is pretty much a requirement of a good software project. And ASP.NET MVC lend itself much better to unit testing than ASP.NET web forms.

ASP.NET MVC will not be the thing for everyone. If you are heavy into designers and drag-drop development web forms will be a better match for you. But if you are like me and like working with code ASP.NET MVC is a joy to work with.

The book I keep by my side is Steven Sanderson’s Pro ASP.NET MVC Framework. It has been very valuable, both on giving me a behind the scenes insight and solving some practical issues I ran into.

Error Logging Modules and Handlers for ASP.NET (MVC)

Maurice — Thu, 13 Aug 2009 12:40:20 GMT

I am working on a new ASP.NET MVC app and like so many other applications out there I need to log any errors should they occur. recently I heard about ELMAH Error Logging Modules and Handlers for ASP.NET through this blog post of Scott Hanselman. So as using en existing and proven solution is always better that reinventing the wheel I decided to try ELMAH and see how easy it is to get started.

Well I can only say I am positively amazed at how easy it is.

Starting from scratch it took me less that 2 hours to download and integrate it into my current ASP.NET MVC application and log all errors to SQL Server. That is including security so not everyone can check the error log.

There are lots of additional capabilities I haven’t looked at yet like setting up an RSS feed, emailing or even tweeting errors messages. But judging from the experience so far that should prove easy enough.

My only regret is that I didn’t check it out before.

Checkout the project run by Atif Aziz here.

Enjoy!

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

Getting started with the .NET RIA Services

Maurice — Tue, 30 Jun 2009 16:34:38 GMT

A recent article I wrote for the MSDN website just went live.

Read is here.

Paging with the Silverlight RIA services DomainDataSource

Maurice — Mon, 27 Apr 2009 08:57:46 GMT

Using the declarative DomainDataSource that is part of the upcoming Silverlight 3 RIA services makes it quite easy to work with data. All you need to do is add a DomainDataSource control to the the XAML, point it to the generated DomainContext class (in this case NorthwindContext) and tell it which method to use to load the data from the web service(in this case LoadCustomers). Next add a DataGrid to display the data and you are good to go.

     <UserControl xmlns:dataControls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.DataForm"  x:Class="LOBUsingRIAServices.CustomerListPage"

                 xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"  

                 xmlns:riaControls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Ria.Controls"

                 xmlns:web="clr-namespace:LOBUsingRIAServices.Web"

                 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 

                 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

        <Grid x:Name="LayoutRoot" Background="White">

            <riaControls:DomainDataSource x:Name="CustomerDataSource"

                                          LoadMethodName="LoadCustomers">

                <riaControls:DomainDataSource.DomainContext>

                    <web:NorthwindContext />

                </riaControls:DomainDataSource.DomainContext>

            </riaControls:DomainDataSource>

            <data:DataGrid ItemsSource="{Binding Data, ElementName=CustomerDataSource}" />

        </Grid>

    </UserControl>

Pretty simple and that is the way I like it

Adding paging.

Sometimes the lost of data to load can get somewhat large and you might not want to load all data. In that case all you need to do is add a PageSize and the DomainDataSource will only load enough data to display on a single page. You can do this by just setting the PageSize on the DomainDataSource but as we also need a control to allow the user to page trough the data it is easier to also add the DataPager control. Now you have the option of setting the PageSize on the DomainDataSource or the DataPager. I found that setting it on either would work just was well except for the initial load where the DataPager shows page 0 when the PageSize is set on the DomainDataSource while it is set to 1, the correct value, when set on the DataPager. I assume this is just a small bug in the current preview.

Another thing you can specify is the LoadSize. This determines how many rows are loaded with each request and if not set equals the PageSize. Setting this to double the PageSize will improve the responsiveness of the the client application so might be a good idea if the data isn’t too large.

    <UserControl xmlns:dataControls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.DataForm"  x:Class="LOBUsingRIAServices.CustomerListPage"

                 xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"  

                 xmlns:riaControls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Ria.Controls"

                 xmlns:web="clr-namespace:LOBUsingRIAServices.Web"

                 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 

                 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

        <Grid x:Name="LayoutRoot" Background="White">

            <riaControls:DomainDataSource x:Name="CustomerDataSource"

                                          LoadMethodName="LoadCustomers"

                                          LoadSize="40">

                <riaControls:DomainDataSource.DomainContext>

                    <web:NorthwindContext />

                </riaControls:DomainDataSource.DomainContext>

            </riaControls:DomainDataSource>

            <data:DataGrid ItemsSource="{Binding Data, ElementName=CustomerDataSource}" />

            <dataControls:DataPager Source="{Binding Data, ElementName=CustomerDataSource}" 

                                    PageSize="20" />

        </Grid>

    </UserControl>

The DataPager control is quite easy to use as well. Just drop it below the DataGrid and point it to the DomainDataSource to use and it just works. One problem I ran into was adding the DataPager above the DataGrid though. When I did that the DataPager didn’t show up on the UI so the user could not page through the data even though it still limited the data to the first page.

Using progressive loading

Another nice option is delayed loading. When using progressive loading all you need to do is specify the LoadSize on the DomainDataSource. The DomainDataSource will now load the specified number of rows, wait a bit and load the next set of rows. It will keep on doing this until all data is loaded. The nice thing here is that all the data is loaded but the UI still stays responsive for the user. De the default interval between load requests is 0.75 seconds but this can be fine tuned using the LoadDelay time span on the DomainDataSource.

    <UserControl xmlns:dataControls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.DataForm"  x:Class="LOBUsingRIAServices.CustomerListPage"

                 xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"  

                 xmlns:riaControls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Ria.Controls"

                 xmlns:web="clr-namespace:LOBUsingRIAServices.Web"

                 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 

                 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

        <Grid x:Name="LayoutRoot" Background="White">

            <riaControls:DomainDataSource x:Name="CustomerDataSource"

                                          LoadMethodName="LoadCustomers"

                                          LoadSize="10"

                                          LoadDelay="0:0:0.25">

                <riaControls:DomainDataSource.DomainContext>

                    <web:NorthwindContext />

                </riaControls:DomainDataSource.DomainContext>

            </riaControls:DomainDataSource>

            <data:DataGrid ItemsSource="{Binding Data, ElementName=CustomerDataSource}" />

        </Grid>

    </UserControl>

And all of this was done without writing any code add everything was completely declarative. Of course it is just a matter of setting properties so doing so from code is easy enough.

Enjoy!

Adding a custom machineKey section to the web.config

Maurice — Wed, 08 Apr 2009 12:41:00 GMT

Normal 0 21 false false false MicrosoftInternetExplorer4  /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}

Normally you should never have to set the <machineKey> in the in the web.config. This is only needed when am ASP.NET site runs on a web farm and in that case the machines in question should be configured using the machineKey instead of individual web applications. However we have run into the following exception a few times: “System.Web.UI.ViewStateException: Invalid viewstate” after leaving the browser idle for some time.

Turns out that the <machineKey> that where supposed to be on the web farm where missing. Now this is a shared hoster so not much we can do about the machine configuration but adding this key to the web.config before deploying is simple enough.

And generating the values to add is simple using this nifty, not my words, little generator.

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

.NET RIA Services and data communication

Maurice — Mon, 06 Apr 2009 13:55:02 GMT

I was working on an article about the .NET RIA Services and decided to fire up Fiddler to take a close look at the data actually passed around. I was sort of expecting to see a WCF REST based approach with XML messages. Turns out I was wrong, though I expect this option will be added in the future.

It turns out the .NET RIA Services use JSON as their serialization format. This is actually kind of nice as the DataContractJsonSerializer is part of the System.ServiceModel.Web assembly and therefore usable by all .NET clients.

The good part is that a .NET RIA Service is also usable from a JavaScript browser based client. So the same .NET RIA Services library gives us lots of client options. Now this was always the plan but it is nice to see that the default already enable it.

And the best thing?

Well that is that I was already using the .NET RIA Services and never even needed to know how the messages where actually send across the wire, something I shouldn't have to worry about when developing a RIA style application. Which is exactly the goal of the .NET RIA Services.

Cool stuff and highly recommended if you want to create browser based LOB apps

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

And now on Twitter at http://twitter.com/mauricedb.

Want to download all MIX sessions?

Maurice — Tue, 31 Mar 2009 06:52:40 GMT

Then you should check Mike Swanson’s blog post here. He has two batch files, the first downloads all MIX session recordings with in the format you like, the second renames them so it is easier to make sense of all the media file names.

If you just want a list of all sessions with download links this page might be the thing for you.

So much better than downloading them by hand. Not as good as going to the MIX itself but if you, like me, couldn’t go it is still a nice way to see all the content.

Enjoy!

Software Development Event march 30th

Maurice — Mon, 23 Mar 2009 15:40:29 GMT

Just one week to go to the next Software Development Event. The schedule with all the sessions is looking good. But this time there is even more!

We will have a Microsoft Surface machine somewhere in the common area for people to try our. And if you have never played, oops tested, with a Surface machine before this is a truly exiting machine!

Just goes to show, the SDN will go to extraordinary efforts to please all attendees

You can see the full schedule here. And don’t forget, we are not in Ede this time but in a great new location in Driebergen.

Hope to see everyone there next week Monday.

www.TheProblemSolver.nl
Wiki.WindowsWorkflowFoundation.eu

And now on Twitter at http://twitter.com/mauricedb.

Using T4 templates with Silverlight

Maurice — Sat, 21 Mar 2009 20:59:34 GMT

Everyone who has Visual Studio 2008 also has T4 templates that can be used to generate code, or anything else textual for that matter. Using T4 should be pretty easy but unfortunately Visual Studio kind of hides the fact, there is no “Add T4 template” option and when you manually add one there is no help whatsoever in the box to create a working template. There are some tools out there that will help some but getting started with a simple template is easy. The following is a simple template to create a simple class

        1: <#@ Template language="C#" #>

       2: <#@ import namespace="System.Collections.Generic" #>

       3: <#

       4:     Dictionary<string, string> props = new Dictionary<string, string>();

       5:     props.Add("FirstName", "string");

       6:     props.Add("LastName", "string");

       7:     props.Add("Age", "int");

       8: #>

       9: namespace T4Test

      10: {

      11:     public class Demo

      12:     {

      13: <#

      14:     foreach (KeyValuePair<string, string> prop in props)

      15:     {

      16: #>

      17:  

      18:         /// <summary>

      19:         /// Get or set the <#= prop.Key #> property.

      20:         /// </summary>

      21:         public <#= prop.Value #> <#= prop.Key #> { get; set; }

      22: <#

      23:     }

      24: #>

      25:     }

      26: }

The template looks nice, specially with the keyword highlighting but unfortunately that is my code snippet for Live Writer at work because Visual Studio only shows this as a single color text. The result is a nice C# class that looks like this:

       1: namespace T4Test

       2: {

       3:     public class Demo

       4:     {

       5:  

       6:         /// <summary>

       7:         /// Get or set the FirstName property.

       8:         /// </summary>

       9:         public string FirstName { get; set; }

      10:  

      11:         /// <summary>

      12:         /// Get or set the LastName property.

      13:         /// </summary>

      14:         public string LastName { get; set; }

      15:  

      16:         /// <summary>

      17:         /// Get or set the Age property.

      18:         /// </summary>

      19:         public int Age { get; set; }

      20:     }

      21: }

Pretty easy to do and a useful technique don’t you think so?

The bad news

So that was rather easy and great for generating business entities with a bunch of properties, all with identical property implementations. And that is exactly what I tend to do in my Silverlight line of business applications. So I decided to try using T4 with a Silverlight project. But unfortunately that didn’t quite work. using exactly the same template I only had the single word “ErrorGeneratingOutput” appear in the output.

The errors where a bit more useful thought.

Error 1 Compiling transformation: The type or namespace name 'CompilerError' does not exist in the namespace 'System.CodeDom.Compiler' (are you missing an assembly reference?)

Error 2 Compiling transformation: The type 'System.CodeDom.Compiler.CompilerErrorCollection' is defined in an assembly that is not referenced. You must add a reference to assembly 'System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.

It turns out Visual Studio uses the project references itself to run the template. And While the System.CodeDom.Compiler namespace exists in Silverlight the required classes like CompilerError and CompilerErrorCollection do not.

This really is a shame as there is really no good reason that T4 templates do not work for Silverlight. All generation is done in Visual Studio, which has access to the full .NET framework, and not at runtime in the browser.

Still enjoy T4 in the full framework.

www.TheProblemSolver.nl
[2]

And now on Twitter at http://www.twitter.com/mauricedb.

Using mouse gestures in an ASP.NET application with jQuery

Maurice — Mon, 16 Feb 2009 14:55:00 GMT

Most applications allow a user to work both with the mouse and with the keyboard. With the mouse that usually means clicking on buttons or, in the case of a web application, on hyperlinks. using mouse gestures is still not all that common though and that is a shame because it is really easy to add to an application and can be a very useful addition of the user.

To demonstrate how easy it is to add mouse gestures to an ASP.NET application I created a small sample to do just that.

To start with I created a real simple ASP.NET page with a label and two buttons. The label contains a number and the clicking either of the buttons will decrease or increase the number. The page looks like this.

Enabling gestures is just a few minutes work .

First I downloaded the latest version of jQuery and the jGesture plug-in.

Wiring the whole thins just takes a few lines of code. In this case I decided to use the left and right gesture as they match the direction of the two arrows on the page. The first thing is to add the two JavaScript file to the page. Next when the page loads we can use the jQuery ready() function to hook up the mouse gesture event handler. Inside our handler we check is the gesture was left or right and if that was the case we just trigger the click action of the appropriate button. Sounds complicated but using jQuery just a few lines of code. The complete JavaScript needed looks like this:

$().ready(function() {

    $().gesture(function(gs) {

        var gestureName = gs.getName();

        if (gestureName == "right") {

            $(".BtnRight").click();

        else if (gestureName == "left") {

            $(".BtnLeft").click();

});

});

With this code in pace all a use has to do is drag the mouse left or right anywhere over the page to increment or decrement the number. And with the default settings it doesn’t even matter which mouse button he uses.

Note that I use the Button CSS classes as selector instead of the button ID. In this case not really needed but un general this approach works much better with ASP.NET because of the name mangling ASP.NET does.

The complete ASP.NET page looks like this:

    <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="Gestures._Default" %>

    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

    <html xmlns="http://www.w3.org/1999/xhtml">

    <head runat="server">

        <title></title>

        <script src="Scripts/jquery-1.3.1.js" type="text/javascript"></script>   1:     2:     <script src="Scripts/jgesture-1.0.3.js" type="text/javascript">   1: </script>   2:     <script type="text/javascript">   3: $().ready(function() {   4:     $().gesture(function(gs) {   5:         var gestureName = gs.getName();   6:         if (gestureName == "right") {   7:             $(".BtnRight").click();   8:         }   9:         else if (gestureName == "left") {  10:             $(".BtnLeft").click();  11:         }  12:     });  13: });  14:       </script>

    </head>

    <body>

        <form id="form1" runat="server">

        <div>

            <table width="100%">

                <col width="50%" />

                <col />

                <col width="50%" />

                <tr>

                    <td align="center">

                        <asp:ImageButton ID="BtnLeft" 

                            ImageUrl="~/Img/Back.png" 

                            runat="server" 

                            OnClick="BtnLeft_Click"

                            CssClass="BtnLeft" />

                    </td>

                    <td align="center">

                        <asp:Label ID="LblNumber" 

                            runat="server" 

                            Text="0" 

                            Font-Size="XX-Large"></asp:Label>

                    </td>

                    <td align="center">

                        <asp:ImageButton ID="BtnRight" 

                            ImageUrl="~/Img/Next.png" 

                            runat="server" 

                            OnClick="BtnRight_Click"

                            CssClass="BtnRight" />

                    </td>

                </tr>

            </table>

        </div>

        </form>

    </body>

    </html>

Enjoy!

Downlaod source code