Peter Tweed

Getting back to it

PeterTweed — Mon, 04 Apr 2011 05:55:52 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2011/04/03/getting-back-to-it.aspx

Hi folks - for the few followers I have, I thought it was about time to get back to you. My blog will be interspersing my traditional .NET focussed entries with some more less traditional, but important to my day to day focus at work, entries about such crazy things as technology strategy, management challenges, program management learnings or reminders from simpler times and fun stuff such as mobile applications, cloud and non .NET technologies.

Well enough for now. I'll be back soon!!!!

Simple Navigation In Windows Phone 7

PeterTweed — Tue, 18 May 2010 05:35:17 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2010/05/17/simple-navigation-in-windows-mobile-7.aspx

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When moving to the mobile platform all applications need to be able to provide different views. Navigating around views in Windows Phone 7 is a very easy thing to do. This post will introduce you to the simplest technique for navigation in Windows Phone 7 apps.

Steps:

1. Create a new Windows Phone Application project.

2. In the MainPage.xaml file copy the following xaml into the ContentGrid Grid:

</StackPanel>

This gives a text box for the user to enter text and a button to navigate to the next page.

3. Copy the following event handler code to the MainPage.xaml.cs file:

private void Button_Click(object sender, RoutedEventArgs e)

{

NavigationService.Navigate(new Uri( string.Format("/SecondPage.xaml?val={0}", ValueTextBox.Text), UriKind.Relative));

}

The event handler uses the NavigationService.Navigate() function. This is what makes the navigation to another page happen. The function takes a Uri parameter with the name of the page to navigate to and the indication that it is a relative Uri to the current page. Note also the querystring is formatted with the value entered in the ValueTextBox control – in a similar manner to a standard web querystring.

4. Add a new Windows Phone Portrait Page to the project named SecondPage.xaml.

5. Paste the following XAML in the ContentGrid Grid in SecondPage.xaml:

This provides a button to navigate back to the first page.

6. Copy the following event handler code to the SecondPage.xaml.cs file:

private void Button_Click(object sender, RoutedEventArgs e)

{

NavigationService.GoBack();

}

This tells the application to go back to the previously displayed page.

7. Add the following code to the constructor in SecondPage.xaml.cs:

this.Loaded += new RoutedEventHandler(SecondPage_Loaded);

8. Add the following loaded event handler to the SecondPage.xaml.cs file:

void SecondPage_Loaded(object sender, RoutedEventArgs e)

{

if (NavigationContext.QueryString["val"].Length > 0)

MessageBox.Show(NavigationContext.QueryString["val"], "Data Passed", MessageBoxButton.OK);

else

MessageBox.Show("{Empty}!", "Data Passed", MessageBoxButton.OK);

}

This code pops up a message box displaying either the text entered on the first page or the message “{Empty}!” if no text was entered.

9. Run the application, enter some text in the text box and click on the next page button to see the application in action:

Congratulations! You have created a new Windows Phone 7 application with page navigation.

Silverlight MEF – Download On Demand

PeterTweed — Sun, 16 May 2010 02:25:03 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2010/05/15/mef--download-on-demand.aspx

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A common challenge with building complex applications in Silverlight is the initial download size of the xap file. MEF enables us to build composable applications that allows us to build complex composite applications. Wouldn’t it be great if we had a mechanism to spilt out components into different Silverlight applications in separate xap files and download the separate xap file only if needed?

MEF gives us the ability to do this. This post will cover the basics needed to build such a composite application split between different silerlight applications and download the referenced silverlight application only when needed.

Steps:

1. Create a Silverlight 4 application

2. Add references to the following assemblies:

System.ComponentModel.Composition.dll

System.ComponentModel.Composition.Initialization.dll

3. Add a new Silverlight 4 application called ExternalSilverlightApplication to the solution that was created in step 1. Ensure the new application is hosted in the web application for the solution and choose to not create a test page for the new application.

4. Delete the App.xaml and MainPage.xaml files – they aren’t needed.

5. Add references to the following assemblies in the ExternalSilverlightApplication project:

System.ComponentModel.Composition.dll

System.ComponentModel.Composition.Initialization.dll

6. Ensure the two references above have their Copy Local values set to false. As we will have these two assmblies in the original Silverlight application, we will have no need to include them in the built ExternalSilverlightApplication build.

7. Add a new user control called LeftControl to the ExternalSilverlightApplication project.

8. Replace the LayoutRoot Grid with the following xaml:

</Grid>

9. Add the following statement to the top of the LeftControl.xaml.cs file

using System.ComponentModel.Composition;

10. Add the following attribute to the LeftControl class

[Export(typeof(LeftControl))]

This attribute tells MEF that the type LeftControl will be exported – i.e. made available for other applications to import and compose into the application.

11. Add a new user control called RightControl to the ExternalSilverlightApplication project.

12. Replace the LayoutRoot Grid with the following xaml:

</Grid>

13. Add the following statement to the top of the RightControl.xaml.cs file

using System.ComponentModel.Composition;

14. Add the following attribute to the RightControl class

[Export(typeof(RightControl))]

15. In your original Silverlight project add a reference to the ExternalSilverlightApplication project.

16. Change the reference to the ExternalSilverlightApplication project to have it’s Copy Local value = false. This will ensure that the referenced ExternalSilverlightApplication Silverlight application is not included in the original Silverlight application package when it it built. The ExternalSilverlightApplication Silverlight application therefore has to be downloaded on demand by the original Silverlight application for it’s controls to be used.

1. In your original Silverlight project add the following xaml to the LayoutRoot Grid in MainPage.xaml:

<Grid.RowDefinitions>

</Grid.RowDefinitions>

</StackPanel>

The borders will hold the controls that will be downlaoded, imported and composed via MEF when the button is clicked.

2. Add the following statement to the top of the MainPage.xaml.cs file

using System.ComponentModel.Composition;

3. Add the following properties to the MainPage class:

[Import(typeof(LeftControl))]

public LeftControl LeftUserControl { get; set; }

[Import(typeof(RightControl))]

public RightControl RightUserControl { get; set; }

This defines properties accepting LeftControl and RightControl types. The attrributes are used to tell MEF the discovered type that should be applied to the property when composition occurs.

17. Add the following event handler for the button click to the MainPage.xaml.cs file:

private void Button_Click(object sender, RoutedEventArgs e)

{

DeploymentCatalog deploymentCatalog =

new DeploymentCatalog("ExternalSilverlightApplication.xap");

CompositionHost.Initialize(deploymentCatalog);

deploymentCatalog.DownloadCompleted += (s, i) =>

{

if (i.Error == null)

{

CompositionInitializer.SatisfyImports(this);

LeftContent.Child = LeftUserControl;

RightContent.Child = RightUserControl;

LoaderButton.IsEnabled = false;

}

};

deploymentCatalog.DownloadAsync();

}

This is where the magic happens! The deploymentCatalog object is pointed to the ExternalSilverlightApplication.xap file. It is then associated with the CompositionHost initialization. As the download will be asynchronous, an eventhandler is created for the DownloadCompleted event. The deploymentCatalog object is then told to start the asynchronous download.

The event handler that executes when the download is completed uses the CompositionInitializer.SatisfyImports() function to tell MEF to satisfy the Imports for the current class. It is at this point that the LeftUserControl and RightUserControl properties are initialized with composed objects from the downloaded ExternalSilverlightApplication.xap package.

18. Run the application click the Download External Controls button and see the controls defined in the ExternalSilverlightApplication application loaded into the original Silverlight application.

Congratulations! You have implemented download on demand capabilities for composite applications using the MEF DeploymentCatalog class. You are now able to segment your applications into separate xap file for deployment.

Composing Silverlight Applications With MEF

PeterTweed — Sun, 09 May 2010 00:43:06 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2010/05/08/composing-silverlight-applications-with-mef.aspx

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Anyone who has written an application with complexity enough to warrant multiple controls on multiple pages/forms should understand the benefit of composite application development. That is defining your application architecture that can be separated into separate pieces each with it’s own distinct purpose that can then be “composed” together into the solution.

Composition can be useful in any layer of the application, from the presentation layer, the business layer, common services or data access. Historically people have had different options to achieve composing applications from distinct well known pieces – their own version of dependency injection, containers to aid with composition like Unity, the composite application guidance for WPF and Silverlight and before that the composite application block.

Microsoft has been working on another mechanism to aid composition and extension of applications for some time now – the Managed Extensibility Framework or MEF for short. With Silverlight 4 it is part of the Silverlight environment. MEF allows a much simplified mechanism for composition and extensibility compared to other mechanisms – which has always been the primary issue for adoption of the earlier mechanisms/frameworks.

This post will guide you through the simple use of MEF for the scenario of composition of an application – using exports, imports and composition.

Steps:

1. Create a new Silverlight 4 application.

2. Add references to the following assemblies:

System.ComponentModel.Composition.dll

System.ComponentModel.Composition.Initialization.dll

3. Add a new user control called LeftControl.

4. Replace the LayoutRoot Grid with the following xaml:

</Grid>

5. Add the following statement to the top of the LeftControl.xaml.cs file

using System.ComponentModel.Composition;

6. Add the following attribute to the LeftControl class

[Export(typeof(LeftControl))]

This attribute tells MEF that the type LeftControl will be exported – i.e. made available for other applications to import and compose into the application.

7. Add a new user control called RightControl.

8. Replace the LayoutRoot Grid with the following xaml:

</Grid>

9. Add the following statement to the top of the RightControl.xaml.cs file

using System.ComponentModel.Composition;

10. Add the following attribute to the RightControl class

[Export(typeof(RightControl))]

11. Add the following xaml to the LayoutRoot Grid in MainPage.xaml:

</StackPanel>

The borders will hold the controls that will be imported and composed via MEF.

12. Add the following statement to the top of the MainPage.xaml.cs file

using System.ComponentModel.Composition;

13. Add the following properties to the MainPage class:

[Import(typeof(LeftControl))]

public LeftControl LeftUserControl { get; set; }

[Import(typeof(RightControl))]

public RightControl RightUserControl { get; set; }

This defines properties accepting LeftControl and RightControl types. The attrributes are used to tell MEF the discovered type that should be applied to the property when composition occurs.

14. Replace the MainPage constructore with the following code:

public MainPage()

{

InitializeComponent();

CompositionInitializer.SatisfyImports(this);

LeftContent.Child = LeftUserControl;

RightContent.Child = RightUserControl;

}

The CompositionInitializer.SatisfyImports(this) function call tells MEF to discover types related to the declared imports for this object (the MainPage object). At that point, types matching those specified in the import defintions are discovered in the executing assembly location of the application and instantiated and assigned to the matching properties of the current object.

15. Run the application and you will see the left control and right control types displayed in the MainPage:

Congratulations! You have used MEF to dynamically compose user controls into a parent control in a composite application model.

In the next post we will build on this topic to cover using MEF to compose Silverlight applications dynamically in download on demand scenarios – so .xap packages can be downloaded only when needed, avoiding large initial download for the main application xap.

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Searching for context in Silverlight applications

PeterTweed — Thu, 06 May 2010 05:51:36 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2010/05/05/searching-for-context-in-silverlight-applications.aspx

A common behavior in business applications that have developed through the ages is for a user to be able to get information or execute commands in relation to some information/function displayed by right clicking the object in question and popping up a context menu that offers relevant options to choose.

The Silverlight Toolkit April 2010 release introduced the context menu object. This can be added to other UI objects and display options for the user to choose. The menu items can be enabled or disabled as per your application logic and icons can be added to the menu items to add visual effect. This post will walk you through how to use the context menu object from the Silverlight Toolkit.

Steps:

1. Create a new Silverlight 4 application

2. Copy the following namespace definition to the user control object of the MainPage.xaml file:

xmlns:my="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Input.Toolkit"

3. Copy the following XAML into the LayoutRoot grid in MainPage.xaml:

</TextBlock>

<my:ContextMenuService.ContextMenu>

<my:ContextMenu >

<my:MenuItem

Header="Copy"

Click="CopyMenuItem_Click" Name="copyMenuItem">

<my:MenuItem.Icon>

</my:MenuItem.Icon>

</my:MenuItem>

<my:Separator/>

<my:MenuItem Name="pasteMenuItem"

Header="Paste"

Click="PasteMenuItem_Click">

<my:MenuItem.Icon>

</my:MenuItem.Icon>

</my:MenuItem>

</my:ContextMenu>

</my:ContextMenuService.ContextMenu>

</Border>

The above code associates a context menu with two menu items and a separator between them to the border object. The menu items has icons associated with them to add visual appeal. The menu items have click event handlers that will be added in the MainPage.xaml.cs code behind in a later step.

4. Add two icon sized images to the ClientBin directory of the web project hosting the Silverlight application, named copy-icon-small.png and paste-icon-small.jpg respectively. I used copy and paste icons as the names suggest.

5. Add the following code to the class in MainPage.xaml.cs file:

private void CopyMenuItem_Click(object sender, RoutedEventArgs e)

{

MessageBox.Show("Copy selected");

}

private void PasteMenuItem_Click(object sender, RoutedEventArgs e)

{

MessageBox.Show("Paste selected");

}

This code adds the event handlers for the menu items defined in step 3.

6. Run the application, right click on the border and select a menu option and see the appropriate message box displayed.

Congratulations it’s that easy!

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Handling null values and missing object properties in Silverlight 4

PeterTweed — Mon, 26 Apr 2010 22:35:09 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2010/04/26/handling-null-values-and-missing-object-properties-in-silverlight-4.aspx

Before Silverlight 4 to bind a data object to the UI and display a message associated with either a null value or if the binding path was wrong, you would need to write a Converter.

In Silverlight 4 we find the addition of the markup extensions TargetNullValue and FallbackValue that allows us to display a value when a null value is found in the bound to property and display a value when the property being bound to is not found.

This post will show you how to use both markup extensions.

Steps:

1. Create a new Silverlight 4 application

2. In the body of the MainPage.xaml.cs file replace the MainPage class with the following code:

public partial class MainPage : UserControl

{

public MainPage()

{

InitializeComponent();

this.Loaded += new RoutedEventHandler(MainPage_Loaded);

}

void MainPage_Loaded(object sender, RoutedEventArgs e)

{

person p = new person() { NameValue = "Peter Tweed" };

this.DataContext = p;

}

public class person

{

public string NameValue { get; set; }

public string TitleValue { get; set; }

}

This code defines a class called person with two properties. A new instance of the class is created, only defining the value for one of the properties and bound to the DataContext of the page.

3. In the MainPage.xaml file copy the following XAML into the LayoutRoot grid:

<Grid.RowDefinitions>

</Grid.RowDefinitions>

<Grid.ColumnDefinitions>

</Grid.ColumnDefinitions>

This XAML defines three textblocks – two of which use the TargetNull and one that uses the FallbackValue markup extensions.

4. Run the application and see the person name displayed as defined for the person object, the expected string displayed for the TargetNullValue when no value exists for the boudn property and the expected string displayed for the FallbackValue when the property bound to is not found on the bound object.

It's that easy!

Formatting made easy - Silverlight 4

PeterTweed — Mon, 26 Apr 2010 06:15:05 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2010/04/25/formatting-made-easy---silverlight-4.aspx

One of the simplest tasks in business apps is displaying different types of data to be read in the format that the user expects them. In Silverlight versions until Silverlight 4 this has meant using a Converter to format data during binding. This involves writing code for the formatting of the data to bind, instead of simply defining the formatting to use for the data in question where you bind the data to the control.

In Silverlight 4 we find the addition of the StringFormat markup extension that allows us to do exactly this. Of course the nice thing is the ability to use the common formatting conventions available in C# through the String.Format function.

This post will show you how to use three of the common formatting conventions - currency, a defined number of decimal places for a number and a date format.

Steps:

1. Create a new Silverlight 4 application

2. In the body of the MainPage.xaml.cs file replace the MainPage class with the following code:

public partial class MainPage : UserControl

{

public MainPage()

{

InitializeComponent();

this.Loaded += new RoutedEventHandler(MainPage_Loaded);

}

void MainPage_Loaded(object sender, RoutedEventArgs e)

{

info i = new info() { PriceValue = new Decimal(9.2567), DoubleValue = 1.2345678, DateValue = DateTime.Now };

this.DataContext = i;

}

public class info

{

public decimal PriceValue { get; set; }

public double DoubleValue { get; set; }

public DateTime DateValue { get; set; }

}

This code defines a class called info with different data types for the three properties. A new instance of the class is created and bound to the DataContext of the page.

3. In the MainPage.xaml file copy the following XAML into the LayoutRoot grid:

<Grid.RowDefinitions>

</Grid.RowDefinitions>

<Grid.ColumnDefinitions>

</Grid.ColumnDefinitions>

This XAML defines three textblocks that use the StringFormat markup extension. The three examples use the C for currency, N3 for a number with 3 decimal places and yyy MM dd for a date that displays year 3 letter month and 2 number date.

4. Run the application and see the data displayed with the correct formatting.

It's that easy!

Slalom Consulting San Francisco Custom Dev Challenge is live!

PeterTweed — Mon, 12 Apr 2010 17:27:47 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2010/04/12/slalom-consulting-san-francisco-custom-dev-challenge-is-live.aspx

The Slalom Consulting San Francisco Custom Dev Challenge is live at www.slalomchallenge.com!!!!!

Slalom Consulting employs world-class technical consultants who take on ground breaking projects. Please take the Slalom Custom Dev Challenge to see how you compare to the level of knowledge we look for in our technical consultants. The online quiz is focussed on General .NET at this time and will be growing to include other technical topics in the future.

This application is written in C#, Silverlight and WCF running deployed in the cloud on Windows Azure and working with SQL Azure and Blob Storage.

SharePoint 2010 is great! Now what do I do?

PeterTweed — Sun, 04 Apr 2010 00:36:14 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2010/04/03/sharepoint-2010-is-great-now-what-do-i-do.aspx

So you have the power of SharePoint 2010 as a platform. What are you going to do now?

How about build upon the power of the SharePoint product and implement solutions to business problems that are intuitive, easy to use, integrated, have a rich user experience and delivered over the web?

Sounds good doesn’t it! Come to the April East Bay .NET User Group meeting and watch to me show you how easy it is to build Silverlight applications on top of SharePoint 2010 that can be quickly developed, delivered and will wow your stakeholders.

See you there!

Silverlight Goes Mobile!

PeterTweed — Sat, 27 Mar 2010 04:16:44 GMT

Originally posted on: http://geekswithblogs.net/PeterTweed/archive/2010/03/26/silverlight-goes-mobile.aspx

The most exciting announcements from Mix 2010 last week for me were the release of the Windows Phone 7 Series SDK and the news that the platform utilizes Silverlight for the application development technology. From the press and exposure that the platform is being given and the experience that is promised it looks like the Windows Phone 7 Series could eventually compete with the iPhone.

For me this is exciting as Silverlight can now be used to develop RIA apps, easily deployed desktop apps and mobile apps. As someone who delivers enterprise technology solutions this equates to a whole bunch of opportunity knocking at the door and asking to join the party.

Watch this space for future posts on developing apps on the Windows Phone 7 Series platform!