Xamarin-EntityFrameworkCore-Sample

This is the Entity Framework Core sample app with Xamarin.Forms.

Prerequisite

This sample app is created under the conditions:

• Visual Studio 2017
• Entity Framework Core version 2.1.4

Remarks

This section is written to show some remarks for using Entity Framework Core in your Xamarin.Forms apps.

Migration tool

You cannot call the migration tool (dotnet ef) in the Xamarin.Forms project directly. Therefore, you need to run the dotnet ef command via the .NET Core console app, which references the Xamarin project.

Under the directory of the console app, you can run the dotnet ef command.

After that, you can create the codes for migration of database.

Build errors in the Xamarin.Android project

The build process of the Xamarin.Android project might failed in error as the following:

Can not resolve reference: System.Buffers, referenced by System.Memory. Please add a NuGet package or assembly reference for System.Buffers, or remove the reference to System.Memory.

You can fix the error by adding System.Buffers NuGet package to your projects.

Linker settings

You need to add the linker settings to your Android/iOS projects to avoid runtime error caused by linker. You can use xml file as the following:

<?xml version="1.0" encoding="utf-8" ?>
<linker>
  <assembly fullname="mscorlib">
    <type fullname="System.String">
      <method name="Compare"></method>
      <method name="CompareTo"></method>
      <method name="ToUpper"></method>
      <method name="ToLower"></method>
    </type>
  </assembly>
  <assembly fullname="System.Core">
    <type fullname="System.Linq.Expressions.Expression`1"></type>
    <type fullname="System.Linq.Queryable"></type>
  </assembly>
</linker>

Set the value of the Build Action property to LinkerDescripton.

Call SQLitePCL.Batteries_V2.Init() in initialization

If you want to use SQLite database, you have to add the initialization codes to your app.

SQLitePCL.Batteries_V2.Init();