Show better error messages in the Add Package Reference dialog when an aggregate exception has an inner aggregate exception.

src/AddIns/Misc/PackageManagement/Project/PackageManagement.csproj

@@ -67,6 +67,7 @@
     <Compile Include="Configuration\AssemblyInfo.cs" />
     <Compile Include="Src\AcceptLicensesEventArgs.cs" />
     <Compile Include="Src\AddPackageReferenceCommand.cs" />
+    <Compile Include="Src\AggregateExceptionErrorMessage.cs" />
     <Compile Include="Src\Design\FakePackageManagementProject.cs" />
     <Compile Include="Src\IAddPackageReferenceView.cs" />
     <Compile Include="Src\IPackageFromRepository.cs" />

src/AddIns/Misc/PackageManagement/Project/Src/AggregateExceptionErrorMessage.cs

@@ -0,0 +1,43 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace ICSharpCode.PackageManagement
+{
+	public class AggregateExceptionErrorMessage
+	{
+		AggregateException ex;
+		StringBuilder errorMessage = new StringBuilder();
+		
+		public AggregateExceptionErrorMessage(AggregateException ex)
+		{
+			this.ex = ex;
+			BuildErrorMessage();
+		}
+		
+		void BuildErrorMessage()
+		{
+			BuildErrorMessage(ex.InnerExceptions);
+		}
+		
+		void BuildErrorMessage(IEnumerable<Exception> exceptions)
+		{
+			foreach (Exception ex in exceptions) {
+				var aggregateEx = ex as AggregateException;
+				if (aggregateEx != null) {
+					BuildErrorMessage(aggregateEx.InnerExceptions);
+				} else {
+					errorMessage.AppendLine(ex.Message);
+				}
+			}
+		}
+		
+		public override string ToString()
+		{
+			return errorMessage.ToString().TrimEnd();
+		}
+	}
+}

src/AddIns/Misc/PackageManagement/Project/Src/PackagesViewModel.cs

@@ -6,7 +6,9 @@ using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.Linq;
+using System.Text;
 using System.Windows.Input;
+
 using NuGet;
 
 namespace ICSharpCode.PackageManagement
@@ -127,16 +129,17 @@ namespace ICSharpCode.PackageManagement
 			base.OnPropertyChanged(null);
 		}
 		
-		protected void SaveError(AggregateException ex)
+		void SaveError(AggregateException ex)
 		{
-			SaveError(ex.InnerException);
+			HasError = true;
+			ErrorMessage = GetErrorMessage(ex);
 			ICSharpCode.Core.LoggingService.Debug(ex);
 		}
 		
-		protected void SaveError(Exception ex)
+		string GetErrorMessage(AggregateException ex)
 		{
-			HasError = true;
+			var errorMessage = new AggregateExceptionErrorMessage(ex);
-			ErrorMessage = ex.Message;
+			return errorMessage.ToString();
 		}
 
 		void UpdatePackagesForSelectedPage(PackagesForSelectedPageResult result)

src/AddIns/Misc/PackageManagement/Test/Src/PackagesViewModelTests.cs

@@ -1080,6 +1080,51 @@ namespace PackageManagement.Tests
 			Assert.AreEqual("Test", viewModel.ErrorMessage);
 		}
 		
+		[Test]
+		public void ErrorMessage_BackgroundTaskHasAggregateExceptionWithNestedInnerAggregateException_ErrorMessageTakenFromInnerException()
+		{
+			CreateViewModel();
+			viewModel.AddSixFakePackages();
+			viewModel.ReadPackages();
+			
+			Exception innerEx1 = new Exception("Test1");
+			Exception innerEx2 = new Exception("Test2");
+			AggregateException innerAggregateEx = new AggregateException(innerEx1, innerEx2);
+			AggregateException aggregateEx = new AggregateException(innerAggregateEx);
+			taskFactory.FirstFakeTaskCreated.Exception = aggregateEx;
+			taskFactory.FirstFakeTaskCreated.IsFaulted = true;
+			CompleteReadPackagesTask();
+			
+			string expectedErrorMessage = 
+				"Test1\r\n" +
+				"Test2";
+			
+			Assert.AreEqual(expectedErrorMessage, viewModel.ErrorMessage);
+		}
+		
+		[Test]
+		public void ErrorMessage_BackgroundTaskHasAggregateExceptionWithTwoInnerExceptionsWhenItFinishes_ErrorMessageTakenFromAllInnerExceptions()
+		{
+			CreateViewModel();
+			viewModel.AddSixFakePackages();
+			viewModel.ReadPackages();
+			
+			Exception innerEx1 = new Exception("Test1");
+			Exception innerEx2 = new Exception("Test2");
+			Exception innerEx3 = new Exception("Test3");
+			AggregateException aggregateEx = new AggregateException(innerEx1, innerEx2, innerEx3);
+			taskFactory.FirstFakeTaskCreated.Exception = aggregateEx;
+			taskFactory.FirstFakeTaskCreated.IsFaulted = true;
+			CompleteReadPackagesTask();
+			
+			string expectedErrorMessage = 
+				"Test1\r\n" +
+				"Test2\r\n" +
+				"Test3";
+			
+			Assert.AreEqual(expectedErrorMessage, viewModel.ErrorMessage);
+		}
+		
 		[Test]
 		public void HasError_ErrorMessageDisplayedAndReadPackagesRetriedAfterFailure_ReturnsFalse()
 		{