Author: Evan Parsons

I was in the position of creating unit tests for a custom web api, and needed to wipe all data in a table before I run my tests.

Here’s the small command I run to delete all rows in the table

        public void deleteAllData() 
        {
            using (var db = new AlertsDbContext()) 
            {
                db.CUSTOMTABLE.RemoveRange(db.CUSTOMTABLE);
                db.SaveChanges();
            }

        }

Remove range takes IENumerable as a parameter. Which is why when you pass it an entire collection, it’ll straight up delete all entries.

I received the following message when deploying after updating my version of Xamarin

Severity	Code	Description	Project	File	Line	Suppression State
Error		Failed to resolve assembly: 'Xamarin.iOS, Version=0.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065'
   at Mono.Cecil.BaseAssemblyResolver.Resolve(AssemblyNameReference name, ReaderParameters parameters)
   at Mono.Cecil.DefaultAssemblyResolver.Resolve(AssemblyNameReference name)
   at Mono.Cecil.MetadataResolver.Resolve(TypeReference type)
   at Mono.Cecil.TypeReference.Resolve()
   at Mono.Cecil.Mixin.CheckedResolve(TypeReference self)
   at Mono.Cecil.SignatureReader.ReadCustomAttributeEnum(TypeReference enum_type)
   at Mono.Cecil.SignatureReader.ReadCustomAttributeElementValue(TypeReference type)
   at Mono.Cecil.SignatureReader.ReadCustomAttributeElement(TypeReference type)
   at Mono.Cecil.SignatureReader.ReadCustomAttributeFixedArgument(TypeReference type)
   at Mono.Cecil.SignatureReader.ReadCustomAttributeConstructorArguments(CustomAttribute attribute, Collection`1 parameters)
   at Mono.Cecil.MetadataReader.ReadCustomAttributeSignature(CustomAttribute attribute)
   at Mono.Cecil.CustomAttribute.<Resolve>b__2(CustomAttribute attribute, MetadataReader reader)
   at Mono.Cecil.ModuleDefinition.Read[TItem,TRet](TItem item, Func`3 read)
   at Mono.Cecil.CustomAttribute.Resolve()
   at Mono.Cecil.CustomAttribute.get_ConstructorArguments()
   at Mono.Cecil.ImmediateModuleReader.ReadCustomAttributes(ICustomAttributeProvider provider)
   at Mono.Cecil.ImmediateModuleReader.ReadMethods(TypeDefinition type)
   at Mono.Cecil.ImmediateModuleReader.ReadType(TypeDefinition type)
   at Mono.Cecil.ImmediateModuleReader.ReadTypes(Collection`1 types)
   at Mono.Cecil.ImmediateModuleReader.ReadModule(ModuleDefinition module)
   at Mono.Cecil.ModuleWriter.WriteModuleTo(ModuleDefinition module, Stream stream, WriterParameters parameters)
   at Mono.Cecil.ModuleDefinition.Write(Stream stream, WriterParameters parameters)
   at Mono.Cecil.ModuleDefinition.Write(String fileName, WriterParameters parameters)
   at Xamarin.Build.Download.XamarinBuildiOSResourceRestore.MergeResources(IAssemblyResolver resolver, String originalAsmPath, String mergedAsmPath, List`1 resourceItems)	CanadianClassifiedsAlerter.iOS

After verifying both my build server and development machine were running the same version of Xamarin, I noticed a slight hint at the end of the message

 at Xamarin.Build.Download.XamarinBuildiOSResourceRestore

Solution

I fixed it by updating Xamarin.Forms and Xamarin.Build.Download in both my Portable project and the iOS project and it built just fine 🙂

It’s that easy.

Effective right now, I will be extending the frequency of checks from the five-ish minutes that users experience now to 12-ish minutes. You will still have your six standard alerts.

I will be offering a pro service to get 45 second checks AND extend the amount of alerts you’re allowed to have to 15 for $65 a month. Please contact me for this service!

Other not as fast but maybe just as good for you plans are:

$40 for every two minutes

$20 for every five

The people interested in this service will be people who make a lot of money off Kijiji, I realize it’s not for everyone.

Why? Are you selling out?

Sort of.

But hear me out… how much money do you think this app makes a month in ad revenue?

$150? $100?

Five bucks.

I make five bucks a month.

This app took 5 months to make as I had to learn how to program for iOS, and I get five bucks a month to show for it.

Weak as shit ad revenue

What are my costs associated with this app?

-Annual Apple Developer Program ($120 a year)

-Power to run my server ($15 a month)

-Cost to build my server ($550)

Not including server upkeep and the initial cost of building the server, it costs me $25 a month to run this service.

I lose money every month by providing this service.

Do you have any other good news?

• If this service takes off, I will be removing ads from the app completely.
• I will more inclined to add new features if the app is making money every month.

Thanks for reading everyone 🙂

If you began to implement Google’s API V3 of their In App Billing Service, and switched to android-inapp-billing-v3 made by anjlab, you might get this error message

The reason this is happening is because you have the same library in there twice. Once from before, and again when his library adds the same files.

The solution is simple, delete the aidl folder in your <project>/app directory. Clean, then rebuild and it will work!

I assume if you’re reading this, you’re familiar with dependency injection in Xamarin Forms. What you’d create in your portable project (Your Xamarin Forms application) is the following

Xamarin.Forms custom class

public interface INotificationsInterface
{
    bool registeredForNotifications();
}

In your Xamarin.iOS project,  implement the interface with the following:

public class NotificationsInterface: INotificationsInterface
{
	public bool registeredForNotifications()
	{
		UIUserNotificationType types = UIApplication.SharedApplication.CurrentUserNotificationSettings.Types;
		if (types.HasFlag(UIUserNotificationType.Alert))
		{
			return true;
		}
		return false;
	}
}

In your main activity for your Xamarin.Forms application, perform the check as follows:

if (DependencyService.Get().registeredForNotifications())
{
	Debug.WriteLine("alerts enabled!");
} else
{
	String warningAboutAlerts ="The point of this applications is instant alerts" +
" but you choose not to receive alerts. You will need to manually check the notifications" +
	   "page or go into your iPhone's system settings to reenable alerts";
	Debug.WriteLine("No alerts allowed!");
	mainLayout.Children.Add(new Label
	{
		Text = warningAboutAlerts,
		TextColor = Color.Red,
		FontSize = 14
	});
	
}

Fairly simple stuff! For my code above, replace mainlayout with whatever you want… a dialogue box, disabling/enabling menu items… it’s entirely up to yourself!

Link to download Canadian Classifieds Alerter: iOS(iPhone) Port

Current status: Running!

Current alert refresh rate: 18-20 minutes

If you want faster alerts, message me!

Monthly pricing for pro version is as follows:

Sidenote: Don’t ever assume I know about a bug. If you’re having an issue, I need to know!

Link to download Canadian Classifieds Alerter: iOS(iPhone) Port

You may have noticed that all the blog posts make mention to commands that don’t exist. Such as update-database and other migration like commands

This is because these classes no longer exist in dotnetcore. If you want to save the changes you’ve made to a database, here are the following commands to issue in a command prompt, power shell or through VS Code

dotnet ef migrations add nameOfMigrationHere

And then run

dotnet ef database update

Check the database of your target and your changes will be there! You’ll even notice a table in your database showing the migration