Saturday, January 6, 2018

VSTS build failed

Recently I was moving a TFS XAML build to one the new style builds.   The XAML based build worked fine but when I tried the new format the build failed with this error

Unable to process command '##vso[task.logdetail id=faad7dd0-d179-4a32-ba2a-cecf68fd7d28;parentid=;

I tried turning off logging in the build and it did not help.  This issue was one of the folder names for the projects.  It contained [ ] in the name which the new Build format does not support.  Removing the [ ]  from the folder name allowed the project to build.  I also had to edit the solution file and update the project folder to the new name

Hope this helps

Sunday, November 5, 2017

Using .net standard 2.0 with a UWP app

With the fall 2017 creators update for windows 10 you can now use .Net standard 2.0 .

First step to use .net Standard 2.0 is to create a new UWP and set the min and max version of UWP version 16299 or higher.

Make sure you update the Nuget packages after you create the app

You need version 6.0.1  Microsoft.NETCore.UniversalWindowsPlatform if you need to use a .net standard 2.0 library.

Tuesday, September 5, 2017

Using .net Standard 2.0 with Xamarin Forms

Standard Libraries are replacing Portable Class Libraries.  Here is how to start using them in Xamarin Forms projects today.

To Start with create a new Xamarin forms app that uses a Portable Class Library

Since UWP will nor support .net Standard Libraries for a few months I would press cancel if you get the dialog asking what version of UWP you want to support.

Right click on the solution and select add new project.  Add a class library (.net standard)

Now drag the files App.Xaml and MainPage.Xaml from the PCL to the new class library.  You can also delete the file Class1.cs in the standard library we  created.

Open the properties for the Standard class library and change the default namespace to be the same as the portable class libraries

Time to add a NuGet package to the standard class library.  Microsoft.NetCore.Portability.Compatibility.  This will help prevent some build errors

Remove the portable class library from the solution.  Right click on the solution and select mange NuGet packages for the solution.  Select Updates and find Xamarin Forms.  Select the latest pre release and make sure the standard library is checked.  The latest prerelease supports standard libraries

Right click on the standard class library and select edit csproj.  Remove the following lines from the file.

    <EmbeddedResource Include="App.xaml">
    <EmbeddedResource Include="MainPage.xaml">

Save the file and add a reference in the android and ios project to the new standard library

Now you can run it

Here is what it looks like in the android emulator

In the next post in this series we will call a web service and save the json we get back to a file on the device.

Sunday, September 3, 2017

Client NoSql DB

I have used the NoSql database Lex.DB in some of my mobile apps in the past.  The DB was actually very handy and it worked on Xamarin.iOS, Xamarin.Android, Windows phone 8+, UWP,  PCL, Silverlight, and WinRT+.  I am in the process of converting the project to a standard library 2.0 that you can use with net core, Xamarin, UWP when the fall creators update comes out in Oct 2017, and .net 4.6.1

My hope is to get the Database so it can be used in windows, linux, mac, xamarin, or UWP apps.  This database is meant to be used with an app not as a server based NoSql database.

The code is currently in GitHub please report any bugs or feature requests there. Send me an email if you want to contribute to the project

Sunday, August 27, 2017

Using Entityframework core 2.0 with xamarin for android

In this post we are going to use the entity framework core 2.0 with a Xamarin for Android project

I am using Visual Studio 2017 (version 15.3)

I also installed .Net Core 2.0 from

Once you have dot net core 2.0 installed which includes .net standard 2.0 lets start by creating a new Xamarin.Android project

First Create a Blank Xamarin for Android app

Once that is added right click on the project and select Manage NuGet Package

Add the package microsoft.entityframeworkcore.sqlite

Add the package and you will see it installs a few extra packages with it.  After it is installed I will update any packages that have updates available.

Lets add a Entities Folder to the android solution and create 2 code files Monkey.cs and MonkeyContext.cs

Monkey class

public class Monkey
public int id { get; set; }
public string monkeyType { get; set; }

MonkeyContext class

    public class MonkeyContext : DbContext
        private string DatabasePath { get; set; }
        public MonkeyContext(string databasePath)
           DatabasePath = databasePath;
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)

        public DbSet<Monkey> Monkeys {get;set;}

In the MainActivity  change the code in MainActivity to this. The code will create the database and add 5 monkeys to the database if there are not any records.  I also changed the MainActivity to inherit from ListActivity so it show the items in the database is a list

   public class MainActivity : ListActivity
        MonkeyAdapter adapter;

        protected override async void OnCreate(Bundle savedInstanceState)
            List<Monkey> lst = null;
            string path = Path.Combine(System.Environment.GetFolderPath(System.Environment.SpecialFolder.MyDocuments), "monkeys.db");
            using (var db = new MonkeyContext(path))
                await db.Database.EnsureCreatedAsync();
                if (!db.Monkeys.Any())
                    db.Monkeys.Add(new Monkey { monkeyType = "Squirrel Monkey" });
                    db.Monkeys.Add(new Monkey { monkeyType = "Spider Monkey" });
                    db.Monkeys.Add(new Monkey { monkeyType = "Golden Lion Tamarin" });
                    db.Monkeys.Add(new Monkey { monkeyType = "Howler Monkey" });
                    db.Monkeys.Add(new Monkey { monkeyType = "Owl or Night Monkey" });
                    await db.SaveChangesAsync();
                lst = db.Monkeys.ToList();

            adapter = new MonkeyAdapter(this, lst);
            ListAdapter = adapter;

The code for MonkeyAdapter.   This code is needed to show the data in a list

   public class MonkeyAdapter : BaseAdapter<Monkey>
        private readonly List<Monkey> data;
        private readonly Activity context;
        public MonkeyAdapter(Activity activity, IEnumerable<Monkey> monkeys)
            data = monkeys.OrderBy(s =>;
            context = activity;

        public override long GetItemId(int position)
            return position;

        public override Monkey this[int position]
            get { return data[position]; }

        public override int Count
            get { return data.Count; }

        public override View GetView(int position, View convertView, ViewGroup parent)
           var view = convertView;
           if (view == null)
                view = context.LayoutInflater.Inflate(Android.Resource.Layout.SimpleListItem1, null);

            var monkey = data[position];
            var text = view.FindViewById<TextView>(Android.Resource.Id.Text1);
            text.Text = monkey.monkeyType;
            return view;

Once you run the project it will add a few items to the database and show them in a list view

You can download  a sample from my CodeImpact demo at GitHub

Code Impact 2017

I spoke at the 2017 Code Impact in Jacksonville Florida on Aug 26.    The sample code and power point for my talk on Use .Net Standard with Xamarin forms can be found on my Git Hub repo.

Wednesday, March 8, 2017

VS 2017 setup the product definitions failed to load

I tried to upgrade my Visual Studio 2017 RC to the release version and got an error product definitions failed to load

The way I got the installer to work was to delete the folder  %LocalAppData%\Microsoft\VisualStudio\Packages\ 

After that running the installer I was able to update my install to the released version

VSTS build failed