Silverlight User Control Navigation Solution

There are two solution approaches when implementing a navigation solution, the capability to navigate between pages using Silverlight. One approach is to use user controls and is what this write-up focuses on the other approach which was recently added in Silverlight 4. For the most part this is a summary of the demo video provided by Jesse Liberty from Microsoft.

Steps for Creating a User Control Navigation solution
1. Create Silverlight Application
2. Add a new page called NavigationFrame
a. Delete the Grid control LayoutRoot in the NavigationFrame.xaml file
b. In the code behind file add the code below to the constructor to load a default page in this example it is the main page

if (this.Content == null)
{
this.Content = new MainPage();
}

c. Add a navigate method to change the content displayed in the page

public void Navigate(UserControl nextPage)
{
this.Content = nextPage;
}
3. Update the App.xaml.cs to load the NavigationFrame Page instead of the MainPage on Application load
a. In the Application_Startup method change MainPage to NavigationFrame
4. Create another Silverlight page called Page_2
5. Add navigation Controls
a. In my case I am using buttons for navigation and added them to both pages (MainPage and Page_2)

<button name="buttonSwitch" type="submit" width="75" content="Switch" height="23" horizontalalignment="Left" margin="132,212,0,0" verticalalignment="Top" click="Switch_Click">

6. In the code behind of both MainPage and Page_2 the even handler needs to be added to swap between the target pages
a. Example of code behind for Page_2

private void Switch_Click(object sender, RoutedEventArgs e)
{
NavigateFrame ps = this.Parent as NavigateFrame;
ps.Navigate(new MainPage());
}





Reference: User Control Implementations
Jesse Liberty Demo Video - http://www.silverlight.net/learn/videos/silverlight-videos/using-multiple-pages-part-1/
Slightly Different implementation use a service approach- http://nerddawg.blogspot.com/2008/06/pages-in-silverlight.html
Similar example - http://www.c-sharpcorner.com/UploadFile/nipuntomar/Silverlight07082008154003PM/Silverlight.aspx

Navigation Application (SL4)
Basic implementation write up- http://www.silverlighttoys.com/Tutorials.aspx?tutorial=1
Detailed write-up - http://stuff.seans.com/2010/05/07/silverlight-4-project-types-part-ii-%E2%80%93-silverlight-navigation-application/

JQuery Resources

With the recent uptick in JQuery as a go to client side technology, I wanted to share these resources I recently found.

This is a nice article describing the role of JQuery and ASP.NET as well as some well-founded conjecture on the future of Microsoft support of JQuery.
http://visitmix.com/Articles/Javascript-Libraries-and-ASPNET

This is an online training guide, I’ve only skimmed the content but it looks like a fantastic resource.
http://jqfundamentals.com/book/book.html

Accessing the UI thread in Silverlight

I’m creating a separate class where I want to move all related Client Object Model (COM) code.

In my case for the COM code to work it must update the UI thread. To accomplish this I had to move the reference from the main page, which was apparently passing through the Deployment object, to explicitly calling the Deployment object.

So in the case of the main page or I suspect any xmal pages code behind use this line of code in the ClientRequestSucceededEventHandler method:

this.Dispatcher.BeginInvoke(updateUI);


For separate classes to gain access to the UI thread use this line of code in the ClientRequestSucceededEventHandler method:

Deployment.Current.Dispatcher.BeginInvoke(updateUI);



Reference:
http://www.go4answers.com/Example/error-invalid-cross-thread-access-48335.aspx
Using Silverlight Object Model: http://msdn.microsoft.com/en-us/library/ee538971.aspx

Silverlight Export to Excel

The latest thing I’ve been working on is exporting to Excel from my Silverlight Indicator.

With Silverlight 4 there are two problem domains, In Browser and Out of Browser.

The Out of Browser mode is dead easy using Automation Factory. For it to function it does require the Silverlight App to be locally installed with elevated permissions. There are several examples out there, on the web, of this type of implementation now I leveraged the approach posted by Pradeep at c-sharecorner.com for my application, see his code below. This is a great solution that opens the exported data in an excel spreadsheet.


Solution using Out of Browser Mode
Add reference to Microsoft.CSharp.dll to the project.


using System.Runtime.InteropServices.Automation;
…

///

///This code has been leveraged from the following site:
///http://www.c-sharpcorner.com/UploadFile/pchandraker/1899/
///
///

private void btnExport_Click(object sender, RoutedEventArgs e)
{
dynamic excelApp;
excelApp = AutomationFactory.CreateObject("Excel.Application");
excelApp.Visible = true;
dynamic workbook = excelApp.workbooks;
workbook.Add();
dynamic sheet = excelApp.ActiveSheet;
dynamic cell = null;
int index = 1;
foreach (Employee emp in EmployeeGrid.ItemsSource)
{
cell = sheet.Cells[index, 1];
cell.Value = emp.EmployeeName;
cell = sheet.Cells[index, 2];
cell.Value = emp.EmployeeId;
cell = sheet.Cells[index, 3];
cell.Value = emp.Department;
index++;
}
}

Reference links –
Automation API - http://msdn.microsoft.com/en-us/library/ff457794(v=VS.95).aspx
More documentation - http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.automation.automationfactory(VS.95).aspx
A slightly different implementation - http://www.codeproject.com/KB/silverlight/SL4InteropWithExcel.aspx
A similar implementation - http://deepumi.wordpress.com/2010/06/01/export-datagrid-to-excel-in-silverlight-4-0/

Solution using In Browser Mode

With the Out of Browser Domain covered, I needed to tackle the In Browser Domain. To my surprise there wasn’t as many solutions as I thought there would be out there. Exporting a datagrid to excel would seem like a common enough task. Though I did find one gem in the rough Raelango on codeproject.com had posted a nice solution that works great if the columns are TextColumns or are TextBlocks in a template column. It defiantly got me pointed in the right direction. You can see his solution here: http://www.codeproject.com/KB/silverlight/SilverlightDataGridExport.aspx

I took a similar approach though I ended up customizing the code to fit my customized data types. It led to a nice solution which saves to an XML or CSV file based on the user choice through a standard save dialog.

Libraries for Client Object Model

Ok this falls in to information I’ve had to look-up a couple times now. So I’m posting this to my blog for quick reference in the future.

Libraries required for SharePoint development using Client Object Model

The two files for Silverlight are:
Microsoft.SharePoint.Client.Silverlight.dll
Microsoft.SharePoint.Client.Silverlight.Runtime.dll

They can be located on the server at %ProgramFiles%\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\LAYOUTS\ClientBin

For sandbox solutions you need:
Microsoft.SharePoint.Client.dll
Microsoft.SharePoint.Client.Runtime.dll

These are located on the server at %ProgramFiles%\Common Files\Microsoft Shared\web server extensions\14\ISAPI

Getting the URL Parameter Using C#

As I’ve been working with the SharePoint COM API in Silverlight more things that were really hard to do or nearly impossible to do with SharePoint Designer (SPD) have become easier. One of the first things I need to do was link the Silverlight applications and my existing pages together which I felt was really easy to do by passing Query String Parameters.

This is really easy to do in C# with the Windows.Browser namespace.

Here is the method I use to accomplish this.

private string getURLParam(string key)
{
string value = "";
HtmlPage.Document.QueryString.TryGetValue(key, out value);
return value;
}

Now I can provide whatever key I would like to consume, in my case a row ID so I know which record to query in the SharePoint list.

Alien Earth Review

Alien Earth by Megan Lindholm

Overall Grade C

This book takes place in a dystopian future long after the earth had been abandoned due to humans killing the planet. Humans are assisted in leaving the planet by the Arthropiana who travel in Beastships which are capable of interstellar travel.

The story is centered on a human crew of the Beastships who are traveling back to earth and the interaction with the Arthropiana co-captain.

Unfortunately the story seemed fairly predictable from plot to the characters, though the character development was paced ok. The one thing I liked, even though I knew how it was going to end by about halfway through, was the ending I felt it really delivered though getting there took a very predictable path.

http://www.meganlindholm.com/novels/alien-earth/