GridView Scroll to a desired group in a Windows Store App

By default, in a Windows Store App, the focus in a GridView is given to the element "0" of the group "0". But what if you wanto to change this behaviour and make it "open" to another element?

To do it, you have to manage the  itemGridView_Loaded event and use the CollectionView:

In XAML:

<GridView

    x:Name="itemGridView"

    AutomationProperties.AutomationId="ItemGridView"

    AutomationProperties.Name="Grouped Items"

    Grid.RowSpan="2"

    Padding="116,137,40,46"

    ItemsSource="{Binding Source={StaticResource groupedItemsViewSource}}"

    ItemTemplate="{StaticResource Standard250x250ItemTemplate}"

    SelectionMode="None"

    IsSwipeEnabled="false"

    IsItemClickEnabled="True"

    ItemClick="ItemView_ItemClick"

    Loaded="itemGridView_Loaded">

Incode-behind:

private bool firstTime = true;
        
   private void itemGridView_Loaded(object sender, RoutedEventArgs e)
   {
        ICollectionView view;
        ICollectionViewGroup myGroup;
        Data.MyDataType myItem;
 
        if (!this.firstTime) return; else firstTime = false;
        view = itemGridView.ItemsSource as ICollectionView;
        view.CurrentChanged += view_CurrentChanged;
        int groupIndex = 2; // an integer value between 0 and # of items in the groups collection
        myGroup = view.CollectionGroups[groupIndex] as ICollectionViewGroup;
        myItem = recipeGroup.GroupItems[0] as Data.MyDataType;
        view.MoveCurrentTo(myItem);
    }
     
    private void view_CurrentChanged(object sender, object e)
    {
        ICollectionView view;
        Data.MyDataType  myItem;
         
        view = itemGridView.ItemsSource as ICollectionView;
        view.CurrentChanged -= view_CurrentChanged;
        myItem = view.CurrentItem as Data.MyDataType;
        itemGridView.ScrollIntoView(view.CurrentItem, ScrollIntoViewAlignment.Leading);
    }

Privacy Policy in Charm Bar: the easiest way

When you make a Windows Store App, if it uses any Network connection, you have to specify your Privacy Settings in both Store page and Charm Bar.

But how to do it? What's the simplest way?

So, here's the answers.

Do the following in your App.xaml.cs:

1) Add the namespaces

using Windows.UI.ApplicationSettings;
using Windows.UI.Popups;

2) Add the handler during app initialization (into OnLaunched())

SettingsPane.GetForCurrentView().CommandsRequested += SettingCharmManager_CommandsRequested;

3) Add my handler that shows the privacy text

private void SettingCharmManager_CommandsRequested(SettingsPane sender, SettingsPaneCommandsRequestedEventArgs args)
{

    args.Request.ApplicationCommands.Add(new SettingsCommand("privacypolicy", "Privacy policy", OpenPrivacyPolicy));

}

4) Add OpenPrivacyPolicy method

private async void OpenPrivacyPolicy(IUICommand command)

{

    Uri uri = new Uri("http://my_website/my_privacy.html");
    await Windows.System.Launcher.LaunchUriAsync(uri);

}

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SharePoint 2013: The username is invalid. The account must be a valid domain account

When configuring SharePoint 2013 in “Complete” mode you get a “The username is invalid. The account mist be a valid domain account” when using a local account to configure the farm…

Out of the box SharePoint only supports “Stand-alone” mode for non domain environments, but this forces you to use SQL Server 2008 R2 Express Edition which is most cases is unacceptable.

The solution is to use a PowerShell command to create the initial configuration of the farm with a local account:

1) Start the SharePoint PowerShell (not the "standard" one)

2) Run “New-SPConfigurationDatabase” from the command line and follow the instructions. This will create the farm and configure the necessary accounts.

3) Rerun the Configuration wizard. After it finishes start the Config Wizard (interactive or not) and configure your server with all components

LINQ Optimization tips

1. Any or Count?
When you have to test for the presence of at least one element into a list, use

        if (query.Any())

Instead of

        if (query.Count() > 0)

That way it only needs to find the first match.

2. Conditions
Use

        query.FirstOrDefault(x => x.value > 1);
        query.SingleOrDefault(x => x.value > 1);

Instead of

        query.Where(x => x.value > 1).FirstOrDefault();
        query.Where(x => x.value > 1).SingleOrDefault();

That way it only does one operation instead of two concatenated operations

3. Understand how it works
You always need to struggle for performance as a LINQ Developer; perhaps because to understand better how internal mechanism works.

        using (MYDataContext context = new MYDataContext())
        {
            var customers = from cust in context.Customers
                            select cust;
            foreach (var customer in customer)
                Response.Write(customer.CustomerAddresses.Count().ToString());
        }

In above example, you will see in Sql Server Profiler that for each customer one query will be executed additional each times to get the total addresses count for that customer when you enumerates in foreach loop. Now, consider below re-written snippet:

        using (MYDataContext context = new MYDataContext())
        {
            var customers = from cust in context.Customers
                            select cust;
            DataLoadOptions dataLoadOptions = new DataLoadOptions();
            dataLoadOptions.LoadWith(A => A.CustomerAddresses);
            context.LoadOptions = dataLoadOptions;
            foreach (var customer in customer)
                Response.Write(customer.CustomerAddresses.Count().ToString());
        }

Simply in above example, with DataLoadingOptions we are infect just telling LINQ Query engine that while it fetches the Customer data; also fetch associated CustomerAddresses table record count for that particular Customer. The benefit is; only ONE query will be executed to get the final result.

4. Finally
The success behind a LINQ application that you develop lies behind the performance of the query that you formulate. You can use any third party tool like I prefer to use LINQPad (by Joseph Albahari) while my development with LINQ. Actually, quick since a long time after I got to know about this tool and I was impressed so much that I thought to why not I get aware something about such nice and intelligent tool before. Life would have become easier!