Windows: Set Environment variables for users

For some cases you might need to set environment variables for your .NET application.
This is true to .NET core too, when you are storing your application settings in these variables.

How to set up a script for the job

It’s handy to create a windows command line script for creating these variables, because when you are on a new work environment, than you don’t need to look up the keys and values.

So bring up your most-loved text editor, make your environment_variable_creator.bat, and add the following code:

@echo on
SETX VARIABLE1 VALUE
SETX PREFIX_VARIABLE2 true
pause

If you are using .NET core’s configuration builder with a prefix like this:

				ConfigurationBuilder cfgBuilder = new ConfigurationBuilder();
				cfgBuilder.AddEnvironmentVariables("PREFIX_");
				IConfigurationRoot configuration = cfgBuilder.Build();
				var value = configuration["VARIABLE2"];

Then you need to set your variables with prefix “PREFIX_” in the bat file. In this scenario, VARIABLE1 can not be read, because it does not contain the prefix.

The code sets the variables only for your user account, not for others. You can parameterize the SETX command to set the settings for a different user, but i recommend, to run the script with a command line for the targeted user, because its much easier.

To run your script under other users name, then open your command prompt with ‘Run as… different user’

.NET Core: Using AssemblyInfo shared between assemblies

There was a time when project.json has replaced the AssemblyInfo. But since .NET core uses .csproj, instead of the project.json, AssemblyInfo comes to the development again.

If you want to version your several different assemblies together, then follow this tutorial.

Add a shared AssemblyInfo.cs

Right click on your solution, and select Add > New Item..

In the following screen, select Visual C# class, and name it as ‘AssemblyInfo.cs’

Replace the file content with the example below:

using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

// General Information about an assembly is controlled through the following 
// set of attributes. Change these attribute values to modify the information
// associated with an assembly.
[assembly: AssemblyVersion("1.0.0")]
[assembly: AssemblyFileVersion("1.0.0")]
[assembly: AssemblyDescription("Insert your description here")]
[assembly: AssemblyCompany("YourAwesomeCompany")]
[assembly: AssemblyCopyright("Copyright © YourAwesomeCompany 2021")]

Set your projects to use the shared assembly info

Do this all of your projects where you want to use the shared assembly info file.

Edit your project file with a text editor (or right click on project > Edit project file)

Add the following tag to the PropertyGroup tag in order to diable automatic assemblyinfo.cs generation:

<PropertyGroup>
....
  <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
....
</PropertyGroup>

Add the shared assembly info to be used with inserting the following tags to between the project tags:

  <ItemGroup>
    <Compile Include="..\AssemblyInfo.cs" Link="Properties\AssemblyInfo.cs" />
  </ItemGroup>

If the project has no Properties folder, like .NET Standard projects basically do, then add the new folder also with this snippet:

  <ItemGroup>
    <Folder Include="Properties\" />
  </ItemGroup>

Xamarin Forms: Close applications programmatically

In some scenarios, we need to programmatically close our application. We can do it in our common code with Xamarin Forms too. Buuuuuut …….

Can we close an iOS application?

There is no API provided for gracefully terminating an iOS application.

In iOS, the user presses the Home button to close applications. Should your application have conditions in which it cannot provide its intended function, the recommended approach is to display an alert for the user that indicates the nature of the problem and possible actions the user could take — turning on WiFi, enabling Location Services, etc. Allow the user to terminate the application at their own discretion.

Do not call the exit function. Applications calling exit will appear to the user to have crashed, rather than performing a graceful termination and animating back to the Home screen.

Source: https://developer.apple.com/library/archive/qa/qa1561/_index.html

Close on Android from Forms code

There is one important place to implement closing apps from code: When you are handling back button presses by yourself.

Imagine, that you have a main screen, which is the root page. When a users presses the hardware back button you should display a confirmer, that says “Do you really want to close the application?”

If the user choose yes, you should make a call like this:

					DependencyService.Get<IPlatformSpecificService>().CloseApplication();

The definition of the IPlatformSpecificService should be look like this:

	public interface IPlatformSpecificService
	{
		void CloseApplication();
	}

And the Android implementation of the IPlatformSpecificService should be something like:

using Plugin.CurrentActivity;

[assembly: Dependency(typeof(DeviceSpecificService))]
namespace AnAwesomeCompany.AGreatProduct.Droid.DependencyServices
{
	public class PlatformSpecificService: IPlatformSpecificService
	{
		public void CloseApplication()
		{
			CrossCurrentActivity.Current.Activity.FinishAndRemoveTask();
		}
	}
}

Activity supports a lot of closing methods of the application. FinishAndRemoveTask will clear the app from the recents list too.

Take a look at official Android documentation at: https://developer.android.com/reference/android/app/Activity#finishAndRemoveTask()

Xamarin Forms: Logging with anything from Console to SQLite

And it’s also logging the invoked method name, and the file name containing the method!

My Forms.RecurrenceToolkit NuGet package pack is now extended with logging functionality.

You can use the pre-written Console and SQLite logger without writing much code, or you can implement your own logger in a few lines, and use it instantly simultaneous with other loggers.

Install banditoth.Forms.RecurrenceToolkit.Logging.* packages, and enjoy the painless logging, and focus on the great ideas instead of being a copy paste robot. 🙂

Usage

In your App.xaml.cs, initalize the logger like:

LoggingProvider.Initalize(
	// If you have installed the console logger:
	new ConsoleLogger(),
	// If you have installed SQLite Logger:
	new SQLiteLogger()
	);

The logger is including the calling method’s name, and the .cs file name in the logs. You can access the logger from anywhere by calling these methods:

LoggingProvider.LogCritical("It's a critical message");
LoggingProvider.LogDebug("It's a debug message");
LoggingProvider.LogError("It's an error message");
LoggingProvider.LogException(new Exception(), "It's an exception");
LoggingProvider.LogInformation("It's an information message");
LoggingProvider.LogTrace("It's a trace message");
LoggingProvider.LogTrace(new StackTrace());
LoggingProvider.LogWarning("It's a warning message");

By default, the console and the SQLite logger logs exceptions in error level.

You can implement your own logger by deriving from BaseLogger class, like:

public class CustomLogger : BaseLogger
	{
		public CustomLogger() : base(new LoggerOptions()
		{
			IncludeCallerSourceFullFileName = true, // This will print C:/Users/Path/AssemblyFile.cs
			IncludeCallerSourceShortFileName = false, // This will print AssemblyFile.cs
			ExceptionLevel = Enumerations.LogLevel.Error, // The LogExceptions calls routed to log to the loglevel set.
			IncludeCallerMethodName = true // This can print the calling method's name
		})
		{

		}
		
		public override void LogCritical(string criticalMessage, string callerMethod, string filePath)
		{
			// Your own method
		}

		// .. File continues

Follow for more

https://github.com/banditoth/Forms.RecurrenceToolkit

Xamarin and Aspect Orientated Programming

I have started implementing my very first AOP like library, which is now available for testing in NuGet.org as a pre-release version.

This package is a part of my Xamarin.Forms Toolkit, and it is a good time to say thank you for using all of the three packages more than 500 times.
When I had published them, I thought the only user will be me. 🙂

In the first release of the package (1.0.0-pre-01), you can decorate your methods with attributes, in order to listen for Entering the method, and Exiting the method.

This can be handy for example, when you need to log your method invocations (Firebase analytics, Basic logging) or when you need to measure the elapsed time of the method run.

    [ConsoleYaay]
    public void BoringMethod()
    {
        Console.WriteLine(DateTime.Now);
    }

For example, the following code above will result the output below:

yaaay on enter!
2021. 05. 25. 16:56:01
yaaaay on exit

This can be achieved implementing IMethodDecorator class like this:

    [System.AttributeUsage(System.AttributeTargets.Method)]
    public class ConsoleYaay : Attribute, IMethodDecorator
    {
        public ConsoleYaay()
        {

        }

        public void OnEnter()
        {
            Console.WriteLine("yaaay on enter!");
        }

        public void OnExit()
        {
            Console.WriteLine("yaaaay on exit");
        }
    }

Try it in your project

Let’s jump to https://github.com/banditoth/Forms.RecurrenceToolkit/ to see the code, or https://www.nuget.org/packages/banditoth.Forms.RecurrenceToolkit.AOP/ to download it as a package

Future improvements

This package can be improved in a lot of aspects, so stay tuned for more details. Or just simply make a pull request with your ideas 🙂