Navigation Framework In Silverlight:-

Navigation Framework in Silverlight is used to navigate through different pages.Like ASP.Net you can pass query string parameters .For this we have to use System.Windows.Controls.Navigation

Namespace in xaml page.

->Create Silverlight project.

->Add Views folder in Silverlight application.

->Add  Home.xaml, About.xaml, Contact.xaml and ContactByRegion.xaml pages in views folder.

Home.xaml:-

<navigation:Page x:Class="NavigationFramework.Views.Home"

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

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

           xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

           xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

           mc:Ignorable="d"

           xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"

           Title="Home Page" >

    <Grid x:Name="LayoutRoot">

        <TextBlock Text="This is home page..."></TextBlock>

    </Grid>

</navigation:Page>

About.xaml:-

<navigation:Page x:Class="NavigationFramework.Views.About"

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

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

           xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

           xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

           mc:Ignorable="d"

           xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"

           Title="About Page">

    <Grid x:Name="LayoutRoot">

        <TextBlock Text="This is about page..."></TextBlock>

    </Grid>

</navigation:Page>

Contact.xaml:-

<navigation:Page x:Class="NavigationFramework.Views.Contact"

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

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

           xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

           xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

           mc:Ignorable="d"

           xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"

           Title="Contact Page">

    <Grid x:Name="LayoutRoot">

        <Grid.ColumnDefinitions>

            <ColumnDefinition Width="135"></ColumnDefinition>

            <ColumnDefinition Width="100"></ColumnDefinition>

        </Grid.ColumnDefinitions>

        <TextBlock Grid.Column="0" Text="Get Address By Region:"></TextBlock>

        <ComboBox Name="cbRegion" Grid.Column="1" Height="30" VerticalAlignment="Top" SelectionChanged="cbRegion_SelectionChanged">

            <ComboBoxItem  Content="India"></ComboBoxItem>

            <ComboBoxItem Content="US"></ComboBoxItem>

            <ComboBoxItem Content="Srilanka"></ComboBoxItem>

        </ComboBox>

    </Grid>

</navigation:Page>

private void cbRegion_SelectionChanged(object sender, SelectionChangedEventArgs e)

        {

            //Get the selected region.

            ComboBox cb = sender as ComboBox;

            ComboBoxItem item = cb.SelectedValue as ComboBoxItem;

            string region = item.Content.ToString();

            //Gets the service that the host used to navigate to this page and use that service to navigate.

            this.NavigationService.Navigate(new Uri(string.Format("Contact/{0}", region), UriKind.Relative));

        }

ContactByRegion.xaml:-

<navigation:Page x:Class="NavigationFramework.Views.ContactByRegion"

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

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

           xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

           xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

           mc:Ignorable="d"

           xmlns:navigation="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"

           Title="ContactByRegion Page" Loaded="Page_Loaded">

    <Grid x:Name="LayoutRoot">

        <TextBlock Name="txtSelectedRegion"></TextBlock>

    </Grid>

</navigation:Page>

private void Page_Loaded(object sender, RoutedEventArgs e)

        {

            //Check the query string.

            if (this.NavigationContext.QueryString["region"] != null)

            {

                //Get the query string.

                txtSelectedRegion.Text = "You have selected  " + this.NavigationContext.QueryString["region"].ToString() + "  region";

            }

        }

->Open App.xaml file and add UriMappings for each and every page created above.

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

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

             x:Class="NavigationFramework.App"

             xmlns:navcore="clr-namespace:System.Windows.Navigation;assembly=System.Windows.Controls.Navigation">

    <Application.Resources>

        <navcore:UriMapper x:Key="uriMapper">

            <navcore:UriMapping Uri="Home" MappedUri="\Views\Home.xaml"></navcore:UriMapping>

            <navcore:UriMapping Uri="About" MappedUri="\Views\About.xaml"></navcore:UriMapping>

            <navcore:UriMapping Uri="Contact" MappedUri="\Views\Contact.xaml"></navcore:UriMapping>

            <navcore:UriMapping Uri="Contact/{region}"  MappedUri="\Views\ContactByRegion.xaml?region={region}"></navcore:UriMapping>

        </navcore:UriMapper>

    </Application.Resources>

</Application>

->Open MainPage.xaml and  add frame control and use the UriMappings created above.

<UserControl x:Class="NavigationFramework.MainPage"

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

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

    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"

    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"

    xmlns:navcore="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Navigation"

    mc:Ignorable="d">

    <Grid x:Name="LayoutRoot" HorizontalAlignment="Center">

        <Grid.RowDefinitions>

            <RowDefinition Height="20"></RowDefinition>

            <RowDefinition Height="*"></RowDefinition>

        </Grid.RowDefinitions>

        <Grid Grid.Row="0">

            <Grid.ColumnDefinitions>

                <ColumnDefinition Width="50"></ColumnDefinition>

                <ColumnDefinition Width="50"></ColumnDefinition>

                <ColumnDefinition Width="50"></ColumnDefinition>

            </Grid.ColumnDefinitions>

            <HyperlinkButton Grid.Column="0" Background="Gray"  x:Name="hbtnHome" Content="Home" Click="Button_Click"  Tag="Home"></HyperlinkButton>

            <HyperlinkButton Grid.Column="1" Background="Gray" x:Name="hbtnAbout" Content="About" Click="Button_Click" Tag="About" ></HyperlinkButton>

            <HyperlinkButton Grid.Column="2" Background="Gray" x:Name="hbtnContact" Content="Contact" Click="Button_Click" Tag="Contact"></HyperlinkButton>

        </Grid>

        <Grid Grid.Row="1">

            <Grid.RowDefinitions>

                <RowDefinition Height="*"></RowDefinition>

            </Grid.RowDefinitions>

            <Grid.ColumnDefinitions>

                <ColumnDefinition Width="400"></ColumnDefinition>

            </Grid.ColumnDefinitions>

            <navcore:Frame Grid.Row="0" Grid.Column="0" Name="MainFrame" UriMapper="{StaticResource uriMapper}" Source="Home"></navcore:Frame>

        </Grid>

    </Grid>

</UserControl>

Let me know, if you have any feedback. Mail me for source code. Enjoy reading my articles…

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Wcf Service In Windows Azure WorkerRole

Worker roles are mainly used for backgroung processes in windows azure.We can host WCF services in worker role.

->Create new azure project and add new workerrole project.

->Open  ServiceDefinition.csdef file add new endpoint in workerrole tag.

<Endpoints>

      <InputEndpoint name="Rest" protocol="http" port="80" />

</Endpoints>

->Add new IService interface.

Service Interface:

[ServiceContract]

    public interface IService

    {

        [OperationContract]

        [WebGet]

        string SayHello(string name);

    }

->Add new Service class and implement IService interface.

Service Implementation:

[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]

    public class Service : IService

    {

        public string SayHello(string name)

        {

            return "Hello " + name;

        }

    }

->Open WorkerRole.cs class,create serviceHost varaible

 and add CreateServiceHost method to host our Wcf REST service.

//Srvice host varible.

private ServiceHost serviceHost;

private void CreateServiceHost()

{

   //Url of service.

   Uri httpUri = new Uri(String.Format("http://{0}/{1}", RoleEnvironment.CurrentRoleInstance.InstanceEndpoints["Rest"].IPEndpoint.ToString(), "Rest"));

   //Assign url to service host.

   serviceHost = new ServiceHost(typeof(Service), httpUri);

   //Adding endpoint for REST service.

   ServiceEndpoint ep = serviceHost.AddServiceEndpoint(typeof(IService), new WebHttpBinding(), "");

   //Adding behavior for REST service.

   ep.Behaviors.Add(new WebHttpBehavior() { HelpEnabled = true });

   //Open the service host  to start listening for messages.

   serviceHost.Open();

 }

->Call CreateServiceHost function in OnStart() method.

If you follow all these steps and upload it then you got error like below.

HTTP could not register URL http://+:80/Rest/. Your process does not have access rights to this namespace (see http://go.microsoft.com/fwlink/?LinkId=70353 for details). Source:System.ServiceModel.

Solution to this problem is find out the port it needs to open and give the workerrole permission to open the appropriate port.

->Create new console project PortDetect and configure Target framework as 3.5.

->Open Program.cs file and add below code which is used to detect the port and assign permission to open the appropriate port.

class Program

 {

   static void Main(string[] args)

    {

            Process.Start("netsh", string.Format("http add urlacl url=http://+:{0}/Rest user=everyone listen=yes delegate=yes",

                     RoleEnvironment.CurrentRoleInstance.InstanceEndpoints["Rest"].IPEndpoint.Port.ToString()));

    }

  }

 ->Build the project and get the  executable into you workerrole project.

->Set the Copy to Output Directory property of  executable to Copy Always.

-> Open  ServiceDefinition.csdef file specify PortDetect.exe as a startup task.

  <Startup>

    <Task commandLine="PortDetect.exe" executionContext="elevated" taskType="simple">

    </Task>

  </Startup>

That’s it now you can access the RestService  which is hosted(at port 80) on workerrole.

Let me know, if you have any feedback. Mail me for source code. Enjoy reading my articles…

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Silverlight Validation Using INotifyPropertyChanged

If we want to perform validation in silverlight we have to use INotifyPropertyChanged interface which notifies clients that a property value has changed.

Create a user class and implement INotifyPropertyChanged interface.

public class User : INotifyPropertyChanged

{

        //Delegate.

        public event PropertyChangedEventHandler PropertyChanged;

        //Username.

        private string userName;

        public string UserName

        {

            get { return userName; }

            set

            {

                //Validate the username for 6 chars.

                if (value.Length < 6)

                {

                    throw new ArgumentException("User Name should contain atleast 6 chars");

                }

                userName = value;

                RaisePropertyChanged("UserName");

            }

        }

        //Password.

        private string password;

        public string Password

        {

            get { return password; }

            set

            {

                //Validate the password for 6 chars.

                if (value.Length < 6)

                {

                    throw new ArgumentException("Password should contain atleast 6 chars");

                }

                password = value;

                RaisePropertyChanged("Password");

            }

        }

        //Occurs when a property value changes.

        private void RaisePropertyChanged(string propertyName)

        {

            if (this.PropertyChanged != null)

            {

                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));

            }

        }

}

In Login.xaml page:-

<Grid x:Name="LayoutRoot">

        <Grid.RowDefinitions>

            <RowDefinition Height="30"></RowDefinition>

            <RowDefinition Height="30"></RowDefinition>

            <RowDefinition Height="30"></RowDefinition>

        </Grid.RowDefinitions>

        <Grid Grid.Row="0">

            <Grid.ColumnDefinitions>

                <ColumnDefinition Width="250"></ColumnDefinition>

                <ColumnDefinition Width="100"></ColumnDefinition>

            </Grid.ColumnDefinitions>

            <sdk:Label Height="28" Grid.Column="0" HorizontalAlignment="Left"  Name="lblUserName" Content="Enter User Name:" VerticalAlignment="Top" Width="100"/>

            <TextBox Grid.Column="0"  HorizontalAlignment="Right"  Name="txtUserName" VerticalAlignment="Top" Width="150">

                <TextBox.Text>

                    <!--Binding should be twoway-->

                    <Binding Mode="TwoWay" Path="UserName" NotifyOnValidationError="True" ValidatesOnExceptions="True"/>

                </TextBox.Text>

            </TextBox>

        </Grid>

        <Grid Grid.Row="1">

            <Grid.ColumnDefinitions>

                <ColumnDefinition Width="250"></ColumnDefinition>

                <ColumnDefinition Width="100"></ColumnDefinition>

            </Grid.ColumnDefinitions>

            <sdk:Label Height="28" Grid.Column="0" HorizontalAlignment="Left"  Name="lblPassword" Content="Enter Password:" VerticalAlignment="Top" Width="100"/>

            <TextBox Grid.Column="0"  HorizontalAlignment="Right"  Name="txtPassword" VerticalAlignment="Top" Width="150">

                <TextBox.Text>

                    <!--Binding should be twoway-->

                    <Binding Mode="TwoWay" Path="Password" NotifyOnValidationError="True" ValidatesOnExceptions="True"/>

                </TextBox.Text>

            </TextBox>

        </Grid>

        <Button Grid.Row="2" Content="Login" Height="23" HorizontalAlignment="Left" Name="btnLogin" VerticalAlignment="Top" Width="75" />

    </Grid>

In constructor:-

public partial class Login: UserControl

    {

        public Login()

        {

            InitializeComponent();

            //User object.

            User objUser = new User();

            LayoutRoot.DataContext = objUser;

        }

    }

Run the appliction without debugging.

Let me know, if you have any feedback. Mail me for source code. Enjoy reading my articles…

sekhartechblog@gmail.com