Do not send empty search criteria in http request to NuGet repository.

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

@@ -199,7 +199,7 @@ namespace ICSharpCode.PackageManagement
 			if (allPackages == null) {
 				IQueryable<IPackage> packages = GetAllPackages();
 				packages = OrderPackages(packages);
-				packages = packages.Find(searchTerms);
+				packages = FilterPackagesBySearchCriteria(packages);
 				totalItems = packages.Count();
 				allPackages = GetFilteredPackagesBeforePagingResults(packages);
 			}
@@ -212,6 +212,25 @@ namespace ICSharpCode.PackageManagement
 				.OrderBy(package => package.Id);
 		}
 		
+		IQueryable<IPackage> FilterPackagesBySearchCriteria(IQueryable<IPackage> packages)
+		{
+			string searchCriteria = GetSearchCriteria();
+			return FilterPackagesBySearchCriteria(packages, searchCriteria);
+		}
+		
+		string GetSearchCriteria()
+		{
+			if (String.IsNullOrWhiteSpace(searchTerms)) {
+				return null;
+			}
+			return searchTerms;
+		}
+
+		protected virtual IQueryable<IPackage> FilterPackagesBySearchCriteria(IQueryable<IPackage> packages, string searchCriteria)
+		{
+			return packages.Find(searchCriteria);
+		}
+		
 		IEnumerable<IPackage> GetPackagesForSelectedPage(IEnumerable<IPackage> allPackages)
 		{
 			int packagesToSkip = pages.ItemsBeforeFirstPage;

src/AddIns/Misc/PackageManagement/Test/Src/Helpers/TestablePackagesViewModel.cs

@@ -18,6 +18,7 @@ namespace PackageManagement.Tests.Helpers
 		public List<FakePackage> FakePackages = new List<FakePackage>();
 		public int GetAllPackagesCallCount;
 		public int PageCountBeforePackagesFiltered;
+		public string SearchCriteriaPassedToFilterPackagesBySearchCriteria;
 		
 		public TestablePackagesViewModel()
 			: this(new FakePackageManagementService())
@@ -88,5 +89,11 @@ namespace PackageManagement.Tests.Helpers
 		{
 			AddFakePackages(howMany: 3);
 		}
+		
+		protected override IQueryable<IPackage> FilterPackagesBySearchCriteria(IQueryable<IPackage> packages, string searchTerms)
+		{
+			SearchCriteriaPassedToFilterPackagesBySearchCriteria = searchTerms;
+			return base.FilterPackagesBySearchCriteria(packages, searchTerms);
+		}
 	}
 }

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

@@ -1195,5 +1195,45 @@ namespace PackageManagement.Tests
 			
 			Assert.AreEqual(1, viewModel.PackageViewModels.Count);
 		}
+		
+		[Test]
+		public void Search_RepositoryHasPackageWithIdOfEmptyString_SearchCriteriaUsedIsNull()
+		{
+			CreateViewModel();
+			viewModel.PageSize = 2;
+			viewModel.FakePackages.Add(new FakePackage() {
+				Id = "",
+				Description = "abc"
+			});
+			taskFactory.RunTasksSynchronously = true;
+			viewModel.ReadPackages();
+			
+			ClearReadPackagesTasks();
+			
+			viewModel.SearchTerms = "";
+			viewModel.Search();
+			
+			Assert.IsNull(viewModel.SearchCriteriaPassedToFilterPackagesBySearchCriteria);
+		}
+		
+		[Test]
+		public void Search_RepositoryHasPackageWithIdOfWhitespaceString_SearchCriteriaUsedIsNull()
+		{
+			CreateViewModel();
+			viewModel.PageSize = 2;
+			viewModel.FakePackages.Add(new FakePackage() {
+				Id = "",
+				Description = "abc"
+			});
+			taskFactory.RunTasksSynchronously = true;
+			viewModel.ReadPackages();
+			
+			ClearReadPackagesTasks();
+			
+			viewModel.SearchTerms = "   ";
+			viewModel.Search();
+			
+			Assert.IsNull(viewModel.SearchCriteriaPassedToFilterPackagesBySearchCriteria);
+		}
 	}
 }