Mike's Blog: 2010

18/9/10

Sample C#, .NET Framework 3.5 project

I always want to provide possible employers with a sample of my work. I decided to implement a Web Application in C# along with .NET Framework 3.5 in order for employers to get a grasp on whether I am suitable for the job. The project is called NewCertification and it is all about data retrieval and manipulation on the MS SQL Database, by communicating with it using an asmx Web Service

Visit this for some code implemented for the NewCertification project

Find the whole project, along with the Database and its log file in mdf format here

You will probably have to change the connection string in the WebService Web Config file to make a successful connection to the Database

Technologies/Techniques used
·         MasterPages
·         WebServices
·         ADO.NET
·         AJAX
· User roles
· Localization
·         Exception Handling/Logging
·         Authorization/Authentication
·         C# object oriented programming
·         Stored Procedures
·         Cryptography
·         Configuration Files
· CSS Files
·         Encrypted Passwords in Database

Logging in the Web Application

1.       LoginUser.aspx
a.       The user enters a username and password
b.      Online Certification makes a Web Service call to validate the credentials and returns a Dataset
c.       If the Dataset contains no rows, the System alerts that there is no such user
d.      If the Dataset contains more than one row, this means that the user is joined to more than one role. Note that due to the implementation on newUser.aspx, the usernames are unique. The system redirects the user to userRoles.aspx to choose the desired role and continue to the specific homepage.
e.      If the Dataset contains a single row, redirect the user to his/hers homepage according to his/hers role

Authorization/Authentication
All WebContentForms use pageBase as their MasterPage. In the page load event of pageBase, the system checks if the Session userPk, username etc are set which can only be done with proper logging in. If these are not set Online Certification redirects the user to loginAgain.aspx, prompting for logging in. Thus if someone tries to bypass the log in page, by changing the text of the address bar to newUser.aspx for example, he/she will not be able to.

Exception Logging
Just like every system, Online Certification, will face exceptions. In order to provide better and faster support for the users, every exception will be logged in the Database. In the case of an exception, the user will be redirected to the exception page where he/she will receive the exception pk. After that he/she will be able to contact the system developers and provide them the pk, which will help them better understand what went wrong by querying the Database for the StackTrace and Message that corresponds to the specific pk.

1/9/10

Sample C#, Silverlight 4, WCF RIA Service Project

This project is based on the idea presented by Ian Griffiths on MSDN's Channel 9 videos series Hand On Lab Silverlight 4. Ian presented a Business Application, where users can log in and attend events. Unfortunately the project he ended up presenting is not so "Business" like. Ian spends a lot of time on out of browser techniques, Web Cams and Drag & Drop and only 7 minutes on user Authentication.

Another bad thing about his presentation, is that he only presented selecting and updating single entities in the database and not pivot tables, such as users_roles for example, which would be the case of a normalized, business database.

The project I ended up building, is not a business application, but a navigation application. I aim to incorporate user log in, user roles and authentication when Pro Business Application with Silverlight 4 gets shipped from Amazon.

In this project I explore the capabilities of the Entity Framework, Domain Service classes and WCF RIA Services.

Find the project here

I used customization of the Domain Service class produced by VS 2010:

        [Query(IsComposable = false)]
        public Attendee GetAttendee(string name, string surname, string email)
        {
            return this.ObjectContext.Attendees.SingleOrDefault(a => (a.name == name) &&     (a.surname == surname) && (a.email == email));
        }

         [Query(IsComposable = false)]
        public Event_Centers GetEventCenter(int centerPk)
        {
            return this.ObjectContext.Event_Centers.SingleOrDefault(c => c.pk == centerPk);
        }

and also the DomainDataSource provided by RIA Services

                    <riaControls:DomainDataSource AutoLoad="True" d:DesignData="{d:DesignInstance my:MyEventsCourses, CreateList=true}" Height="0" LoadedData="myEventsCoursesDomainDataSource_LoadedData" Name="myEventsCoursesDomainDataSource" QueryName="GetMyEventsCoursesQuery" Width="0">
            <riaControls:DomainDataSource.DomainContext>
                <my1:EventPlannerDomainContext />
            </riaControls:DomainDataSource.DomainContext>
        </riaControls:DomainDataSource>

int selectedEvent = Convert.ToInt32(NavigationContext.QueryString["eventId"]);
myEventsCoursesDomainDataSource.FilterDescriptors.Add(new FilterDescriptor { Operator = FilterOperator.IsEqualTo, PropertyPath = "pk", Value = selectedEvent });

in order to represent the database entities on the UI, either in DataGrids or in Details view, as provided by VS 2010.

To overcome the problem of feeding my DataGrids with pivot tables, I used SQL Views to represent the data

The overall experience was good, although I had problems which included my Entities losing their last characters when trying to generate the ADO.NET Entity Data Model. My entity Users became User and clashed with the built in class User. I also lost Intellisence in the XAML editor when I dragged and dropped a Wrap Panel, not to mention somehow the breakpoints stopped getting hit!!!

I really hope Pro Business Application with Silverlight 4 book meets my expectations, since I haven't found anything yet talking about real Business Apps.

31/8/10

Sample C#, Silverlight 4, WCF project

This project is called The Gardener. It is a C#, .NET, Silverlight application which connects to an MS SQL Server 2008 via WCF Services.

The project in based on the ideas and techniques used in Pro Silverlight 3 in C# and Microsoft Silverlight 4 Business Application Development Beginners Guide books, which provide a great way on getting to know Silverlight 3 and 4 and develop a small scale business application

Find the whole code along with its Database and log file in .mdf format here

The Gardener was built using:

-    MS Visual Studio 2010
-    MS SQL Server 2008
-    Expression Blend 3
-    Silverlight 4
-    WCF Services
-    Pages and Frames for navigation
-    Animations
-    Animation Easing
-    Bing Maps
-    InkPresenter
-    UriMapping
-    Silverlight themes

The Gardener makes use of asynchronous WCF Service calls to store sketches that users make in the Database, by converting the Strokes Collection of the InkPresenter into XML format. Users can after that talk about their dream garden with the people of the Gardener.

The Gardener also uses Bing Maps to pin point the location of the stores upon the map. Bing Maps is the only map control that incorporates fully with Silverlight, as mentioned in Microsoft Silverlight 4 Business Application Development Beginners Guide. Note that you must make an account in Bing Maps and get a key which you must incorporate in the Map control, in your XAML, to get rid of that annoying alert on the Bing Map, which informs you that you provided invalid credentials.

In the Products section, I made use of the Silverlight DataGrid. I must say that this control not only looks great without any customization but it is also very powerful. Sorting, column resizing/moving and field editing with no or with very little code, unlike the ASP.NET GridView.

I used Pages and Frames for navigation in this project, since in this way I can keep track of the browser's history and navigate using the backwards and forward buttons of the browsers.

Animations and Animation Easing gives a better look and feel on the Pages of the application and makes it even better in the eyes of the customers.

Finally, my overall experience using the tools, technologies, techniques and IDEs was great, although I had a little bit of a hard time installing MS SQL Server 2008 and MS Visual Studio on my Windows 7 machine.

Next project I am looking forward to implementing is a full scale business Silverlight 4 application, using the Silverlight business application template of MS Visual Studio 2010 which will connect to the Database using RIA Services. For that I intend to study from Pro Business Applications with Silverlight 4 by Chris Anderson.

25/8/10

Sample C#, .NET Framework 3.5 project

I always want to provide possible employers with a sample of my work. I decided to write a Web Application in C# along with .NET Framework 3.5 in order for employers to get a grasp on whether I am suitable for the job. The project is called NewCertification and it is all about data retrieval and manipulation on the MS SQL Database, by communicating with it using an asmx Web Service

Visit this for some code implemented for the NewCertification project

Find the whole project, along with the Database and its log file in mdf format here

You will probably have to change the connection string in the WebService Web Config file to make a successful connection to the Database

22/7/10

JavaSript to get query string items

I wanted to make my own function in order to get the query string items. The code below initializes an array which will contain queryStringItem objects, with properties name and value. So if the text in the address bar is

http://www.blogger.com/post-create.g?blogID=6495603084419766846

the code will return an array of length 1, which will store an object of type queryStringItem whose name property will be equal to blogID and value property equal to 6495603084419766846.

The code was tested in Internet Explorer 8.0.7600 and Mozilla FireFox 3.5.10

function getQueryStringItemArray() {

    //Check if there is a query string
    if (location.search.length > 0) {

        //Initialize the Array which will store the queryStringItem Objects
        var queryArray = new Array();

        //Get the query string and ommit the ? charqacter
        var queryString = location.search.replace("?", "");

        //Devide the query string into its components (name = value) and store them all in an Array
        //so that each Array slot contains a name = value string
        var queryStringItems = queryString.split("&");

        //Create the queryStringObject for every name = value string created above
        //Push every queryStringObject into the queryArray, so that each slot contains a
        //queryStringObject with properties name and value
        for (var indexOfQueryStringItems = 0; indexOfQueryStringItems < queryStringItems.length; indexOfQueryStringItems++) {
            queryArray.push(createQueryStringItem(queryStringItems[indexOfQueryStringItems]));
        }
    }

    return queryArray;
}

function createQueryStringItem(someString) {

    var queryStringItem = new Object();

    var queryStringItemParts = someString.split("=");

    queryStringItem.name = decodeURIComponent(queryStringItemParts[0]);

    queryStringItem.value = decodeURIComponent(queryStringItemParts[1]);

    return queryStringItem;
}

21/2/10

Developing Silverlight 3.0 Web Applications

    Developing a Silverlight Web application is a great experience. To get started all you need is Visual Studio 2008 with Service Pack 1 installed, Silverlight 3.0 SDK, Silverlight toolkit and Expression Blend 3.0. Expression Blend is needed since Visual Studio 2008 does not have a designer so you will not be able to drag and drop controls like you do in aspx pages. Blend will give you an easy solution to apply positioning etc on your controls, unless you want to do it by configuring the XAML file!!! Anyway Visual Studio 2010 release will have a designer so just be patient...

Download the tools at http://silverlight.net/getstarted/

   Building your first Silverlight Web Application will not be difficult if you are already familiar with XML, since everything that has to do with designing and configuring your pages is done by writing on a XAML file.

If you are unfamiliar with XAML visit http://msdn.microsoft.com/en-us/library/ms752059.aspx

   Building the back bone of a Silverlight Web Application, Visual Studio 2008 gives you the option to create a stand alone Silverlight Application or a solution that contains a Silverlight Application project and a project with the nessecary aspx pages in order to test your application.

   When deploying a Silverlight Web Application keep in mind that not everyone has Silverlight installed on their machines. This means that the end user will be prompted by default to install Silverlight in order to proceed. But not every user is "Computer Friendly", meaning that my father for example will hesitate to install the new technology fearing that Silverlight might be a virus or that malicious code will destroy his computer.

   Quoting a tip in Matthew MacDonald's Pro Silverlight 3 in C#

Studies show that Web Surfers are far more likely to make it through an installation process on the Web if they are guided to do it as a part of an application, rather than prompted to install it as a technology...

This means that users might be suspicious of the Silverlight logo, small banner and the Get Silverlight button that appears on their screen of they do not have Silvelight and try to view your page. To give web surfers a friendlier experience try to customize that content and make it part of your Web Application

A final issue is that of the versioning. Silverlight 4 Beta is already out there. So what will happen if I have Silverlight 3 and try to view a site on Silverlight 4???Again Silverlight will show a dialog box prompting for upgrades etc something that a non "Computer Friendly" person might be suspicious of. The suggestion is to make the upgrade part of your Web Application by customizing its behavior when the version problem occurs.

More on Silverlight about to come...

7/2/10

How to create a web custom control

The way I went about it was to add a class library to my Web Application. After that I made my class eg customGrid inherit from GridView. On the Solution Configuration I changed the setting from Debug to Release in order to get the DLL from the release folder and add the newly built control to my toolbox...

I dragged and dropped the control on my Default.aspx and went on to built the whole prject on debug mode. That's when I got the Warning

Warning 1 Generation of designer file failed: Unknown server tag 'cc1:customGrid1'. C:\Users\MSen\Documents\Visual Studio 2008\Projects\myGridTest2\myGridTest2\Default.aspx 16 0 myGridTest2

This warning makes one unable to access the properties and methods of the new control, trying to set its DataSourse for example, since the Default.aspx.designer.cs does not contain code for our control. Thus the way to go around this warning and become able to access the members of the control is to modify the Default.aspx.designer.cs by including the highlighted code

    public partial class _Default {

        /// <summary>
        /// form1 control.
        /// </summary>
        /// <remarks>
        /// Auto-generated field.
        /// To modify move field declaration from designer file to code-behind file.
        /// </remarks>
        protected global::System.Web.UI.HtmlControls.HtmlForm form1;
        protected global::customControlNamespace.CustomControlName CustomControlID;
    }

The afore mentioned work around will make you able to access te members of the control, but the warning will still appear every time you built the project

Another way to go around it is to open IIS and

1) Go to 'Default Web Site' properties.
2) At 'Web Site' Tab click on 'Advanced..' button.
3) In 'Multiple identities for this site' list select '80:localhost' row and then click 'Edit' button.
4) Erase the 'localhost' string there and click ok.
5) Now close your solution in Visual Studio and open it again.

If IIS is not visible try

Opening Control Panel, Programs & Features, Turn Windows Features on or off, Internet Information Services and choose the IIS Management Console

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