Workaround for NuGet Core not deleting the .addin file of uninstalled package.

src/AddIns/Misc/AddInManager2/AddInManager2.Tests/Fakes/FakeNuGetPackageManager.cs

@@ -73,5 +73,16 @@ namespace ICSharpCode.AddInManager2.Tests.Fakes
        		get;
        		set;
        	}
+       	
+       	public string LocalPackageDirectory
+       	{
+       		get;
+       		set;
+       	}
+    	
+		public string GetLocalPackageDirectory(IPackage package)
+		{
+			return LocalPackageDirectory;
+		}
     }
 }

src/AddIns/Misc/AddInManager2/Project/Src/Model/Interfaces/INuGetPackageManager.cs

@@ -19,5 +19,6 @@ namespace ICSharpCode.AddInManager2.Model
 		}
 		IPackageOperationResolver CreateInstallPackageOperationResolver(bool allowPrereleaseVersions);
 		void ExecuteOperation(PackageOperation operation);
+		string GetLocalPackageDirectory(IPackage package);
 	}
 }

src/AddIns/Misc/AddInManager2/Project/Src/Model/NuGetPackageManager.cs

@@ -96,6 +96,11 @@ namespace ICSharpCode.AddInManager2.Model
 			_packageManager.ExecuteOperation(operation);
 		}
 		
+		public string GetLocalPackageDirectory(IPackage package)
+		{
+			return Path.Combine(PackageOutputDirectory, package.Id + "." + package.Version.Version.ToString());
+		}
+		
 		private IPackageManager EnsurePackageManagerInstance()
 		{
 			if (_packageManager != null)
@@ -110,7 +115,7 @@ namespace ICSharpCode.AddInManager2.Model
 			}
 
 			// Create new package manager instance
-			_packageManager = new NuGetPackageManagerImplementation(_repositories.AllRegistered, _packageOutputDirectory);
+			_packageManager = new NuGetPackageManagerImplementation(_repositories.AllRegistered, _packageOutputDirectory, this);
 			_packageManager.PackageInstalled += _packageEvents_NuGetPackageInstalled;
 			_packageManager.PackageUninstalled += _packageEvents_NuGetPackageUninstalled;
 			return _packageManager;
@@ -136,9 +141,12 @@ namespace ICSharpCode.AddInManager2.Model
 		
 		private class NuGetPackageManagerImplementation : PackageManager
 		{
-			public NuGetPackageManagerImplementation(IPackageRepository sourceRepository, string path)
+			private INuGetPackageManager _internalPackageManager;
+			
+			public NuGetPackageManagerImplementation(IPackageRepository sourceRepository, string path, INuGetPackageManager internalPackageManager)
 				: base(sourceRepository, path)
 			{
+				_internalPackageManager = internalPackageManager;
 			}
 			
 			public void ExecuteOperation(PackageOperation operation)
@@ -146,6 +154,17 @@ namespace ICSharpCode.AddInManager2.Model
 				// Allow to call this method from outside of the class
 				base.Execute(operation);
 			}
+			
+			public override void UninstallPackage(IPackage package, bool forceRemove, bool removeDependencies)
+			{
+				base.UninstallPackage(package, forceRemove, removeDependencies);
+				string localPackageDirectory = _internalPackageManager.GetLocalPackageDirectory(package);
+				if (Directory.Exists(localPackageDirectory))
+				{
+					// Directory still exists after removing the package -> try to delete it explicitly
+					Directory.Delete(localPackageDirectory, true);
+				}
+			}
 		}
 	}
 }

src/AddIns/Misc/AddInManager2/Project/Src/ViewModel/NuGetPackageViewModel.cs

@@ -411,9 +411,7 @@ namespace ICSharpCode.AddInManager2.ViewModel
 				if (IsPackageInstalled())
 				{
 					// Package is already installed, but seems to be not registered as SD AddIn
-					string assumedPackageOutputDir =
+					AddInManager.Setup.InstallAddIn(_package, AddInManager.NuGet.GetLocalPackageDirectory(_package));
-						Path.Combine(AddInManager.NuGet.PackageOutputDirectory, _package.Id + "." + _package.Version.Version.ToString());
-					AddInManager.Setup.InstallAddIn(_package, assumedPackageOutputDir);
 				}
 				else
 				{