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Cross-platform UI Development with Xamarin.Forms

You're reading from   Cross-platform UI Development with Xamarin.Forms

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Product type Paperback
Published in Aug 2015
Publisher
ISBN-13 9781784391195
Length 330 pages
Edition 1st Edition
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Author (1):
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Paul Johnson Paul Johnson
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Paul Johnson
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Table of Contents (22) Chapters Close

Cross-platform UI Development with Xamarin.Forms
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
1. In the Beginning… 2. Let's Get the Party Started FREE CHAPTER 3. Making It Look Pretty and Logging In 4. Making Your Application Portable 5. Data, Generics, and Making Sense of Information 6. A View to a Kill 7. Connect Me to Your Other Services 8. What a Bind! 9. Addressing the Issue 10. This is the World Calling… 11. A Portable Settings Class 12. Xamarin Forms Labs 13. Social Media into the Mix 14. Bringing It All Together Index

LINQ me up baby – yeah!


LINQ gives the developer the power of SQL but for collections. It is not uncommon to order data coming from an SQL database for given parameters (such as searching on a property and outputting the data based on surname and the output ordered DateTime, then the first letter of the first name property), but in terms of collections prior to LINQ manipulation, it literally meant iterating through each piece of data.

In terms of our message collection, we can construct our lists like the following:

  1. From the SQLite database, grab all messages with a parent id of -1.

  2. Using the initial list, perform the following steps:

    1. Iterate through the list.

    2. From the SQLite database, grab messages where parentid == id and store it in a List collection.

  3. On the List, use LINQ to order by DateTime.

  4. Store the ids in a Dictionary collection.

Simple! At the end, there will be a Dictionary with the initial ID followed by the List of IDs.

The code would look like the following. In this example, DBManager...

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