Index: Ringtoets/Integration/src/Ringtoets.Integration.Plugin/FileImporters/ReferenceLineImporter.cs
===================================================================
diff -u -r925d8a1d7dec6ef95d89b2ff67d78c8d5a49387f -rb3d4bbd1f4cff028627bbf1591929a0b67bfccb9
--- Ringtoets/Integration/src/Ringtoets.Integration.Plugin/FileImporters/ReferenceLineImporter.cs	(.../ReferenceLineImporter.cs)	(revision 925d8a1d7dec6ef95d89b2ff67d78c8d5a49387f)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Plugin/FileImporters/ReferenceLineImporter.cs	(.../ReferenceLineImporter.cs)	(revision b3d4bbd1f4cff028627bbf1591929a0b67bfccb9)
@@ -22,11 +22,13 @@
 using System;
 using System.Collections.Generic;
 using System.Drawing;
+using System.Linq;
 using System.Windows.Forms;
 
 using Core.Common.Base;
 using Core.Common.Base.IO;
 using Core.Common.IO.Exceptions;
+using Core.Common.IO.Readers;
 
 using log4net;
 
@@ -98,56 +100,36 @@
         {
             ImportIsCancelled = false;
             changedObservables.Clear();
+
             bool clearReferenceLineDependentData = false;
+
             var importTarget = (ReferenceLineContext)targetItem;
             if (importTarget.Parent.ReferenceLine != null)
             {
-                DialogResult result = MessageBox.Show(Resources.ReferenceLineImporter_ConfirmImport_Confirm_referenceline_import_which_clears_data_when_performed,
-                                                      Resources.ReferenceLineImporter_ConfirmImport_DialogTitle,
-                                                      MessageBoxButtons.OKCancel);
-                if (result == DialogResult.Cancel)
-                {
-                    ImportIsCancelled = true;
-                }
-                else
-                {
-                    clearReferenceLineDependentData = true;
-                }
+                clearReferenceLineDependentData = ConfirmImportOfReferenceLineToClearReferenceLineDependentData();
             }
 
             if (ImportIsCancelled)
             {
-                NotifyProgress(Resources.ReferenceLineImporter_ProgressText_Import_cancelled_no_data_read,
-                               0, clearReferenceLineDependentData ? 4 : 2);
+                HandleUserCancellingImport();
                 return false;
             }
 
-            ReferenceLine importedReferenceLine;
-            try
+            NotifyProgress(Resources.ReferenceLineImporter_ProgressText_Reading_referenceline,
+                           1, clearReferenceLineDependentData ? 4 : 2);
+            ReadResult<ReferenceLine> readResult = ReadReferenceLine(filePath);
+            if (readResult.CriticalErrorOccurred)
             {
-                NotifyProgress(Resources.ReferenceLineImporter_ProgressText_Reading_referenceline,
-                               1, clearReferenceLineDependentData ? 4 : 2);
-                importedReferenceLine = new ReferenceLineReader().ReadReferenceLine(filePath);
-            }
-            catch (ArgumentException e)
-            {
-                HandleCriticalFileReadError(e);
                 return false;
             }
-            catch (CriticalFileReadException e)
-            {
-                HandleCriticalFileReadError(e);
-                return false;
-            }
 
             if (ImportIsCancelled)
             {
-                NotifyProgress(Resources.ReferenceLineImporter_ProgressText_Import_cancelled_no_data_read,
-                               1, clearReferenceLineDependentData ? 4 : 2);
+                HandleUserCancellingImport();
                 return false;
             }
 
-            AddReferenceLineToDataModel(importTarget.Parent, importedReferenceLine, clearReferenceLineDependentData);
+            AddReferenceLineToDataModel(importTarget.Parent, readResult.ImportedItems.First(), clearReferenceLineDependentData);
             return true;
         }
 
@@ -156,6 +138,60 @@
             return changedObservables;
         }
 
+        private bool ConfirmImportOfReferenceLineToClearReferenceLineDependentData()
+        {
+            var clearReferenceLineDependentData = false;
+
+            DialogResult result = MessageBox.Show(Resources.ReferenceLineImporter_ConfirmImport_Confirm_referenceline_import_which_clears_data_when_performed,
+                                                  Resources.ReferenceLineImporter_ConfirmImport_DialogTitle,
+                                                  MessageBoxButtons.OKCancel);
+            if (result == DialogResult.Cancel)
+            {
+                ImportIsCancelled = true;
+            }
+            else
+            {
+                clearReferenceLineDependentData = true;
+            }
+
+            return clearReferenceLineDependentData;
+        }
+
+        private static void HandleUserCancellingImport()
+        {
+            log.Info(Resources.ReferenceLineImporter_ProgressText_Import_cancelled_no_data_read);
+        }
+
+        private ReadResult<ReferenceLine> ReadReferenceLine(string filePath)
+        {
+            try
+            {
+                return new ReadResult<ReferenceLine>(false)
+                {
+                    ImportedItems = new[]
+                    {
+                        new ReferenceLineReader().ReadReferenceLine(filePath)
+                    }
+                };
+            }
+            catch (ArgumentException e)
+            {
+                return HandleCriticalFileReadError(e);
+            }
+            catch (CriticalFileReadException e)
+            {
+                return HandleCriticalFileReadError(e);
+            }
+        }
+
+        private static ReadResult<ReferenceLine> HandleCriticalFileReadError(Exception e)
+        {
+            var errorMessage = String.Format(Resources.ReferenceLineImporter_HandleCriticalFileReadError_Error_0_no_referenceline_imported,
+                                             e.Message);
+            log.Error(errorMessage);
+            return new ReadResult<ReferenceLine>(true);
+        }
+
         private void AddReferenceLineToDataModel(AssessmentSectionBase assessmentSection, ReferenceLine importedReferenceLine, bool clearReferenceLineDependentData)
         {
             NotifyProgress(Resources.ReferenceLineImporter_ProgressText_Adding_imported_referenceline_to_assessmentsection,
@@ -202,12 +238,5 @@
             // TODO: WTI-360 - Clear all 'Toetspeil' calculation output
             //changedObservables.Add(clearedInstance);
         }
-
-        private static void HandleCriticalFileReadError(Exception e)
-        {
-            var errorMessage = String.Format(Resources.ReferenceLineImporter_HandleCriticalFileReadError_Error_0_no_referenceline_imported,
-                                             e.Message);
-            log.Error(errorMessage);
-        }
     }
 }
\ No newline at end of file
Index: Ringtoets/Integration/test/Ringtoets.Integration.Plugin.Test/FileImporters/ReferenceLineImporterTest.cs
===================================================================
diff -u -r925d8a1d7dec6ef95d89b2ff67d78c8d5a49387f -rb3d4bbd1f4cff028627bbf1591929a0b67bfccb9
--- Ringtoets/Integration/test/Ringtoets.Integration.Plugin.Test/FileImporters/ReferenceLineImporterTest.cs	(.../ReferenceLineImporterTest.cs)	(revision 925d8a1d7dec6ef95d89b2ff67d78c8d5a49387f)
+++ Ringtoets/Integration/test/Ringtoets.Integration.Plugin.Test/FileImporters/ReferenceLineImporterTest.cs	(.../ReferenceLineImporterTest.cs)	(revision b3d4bbd1f4cff028627bbf1591929a0b67bfccb9)
@@ -397,7 +397,7 @@
         [Test]
         [TestCase(true)]
         [TestCase(false)]
-        public void Import_CancelImportDuringDialogInteraction_GenerateExpectedProgressMessages(bool acceptRemovalOfReferenceLineDependentData)
+        public void Import_CancelImportDuringDialogInteraction_GenerateCancelledLogMessage(bool acceptRemovalOfReferenceLineDependentData)
         {
             // Setup
             var originalReferenceLine = new ReferenceLine();
@@ -411,23 +411,8 @@
 
             var referenceLineContext = new ReferenceLineContext(assessmentSection);
 
-            var expectedProgressMessages = new[]
-            {
-                new ExpectedProgressNotification { Text = "Referentielijn importeren afgebroken. Geen data ingelezen.", CurrentStep = 0, MaxNrOfSteps = acceptRemovalOfReferenceLineDependentData ? 4 : 2 }
-            };
+            var importer = new ReferenceLineImporter();
 
-            var progressChangedCount = 0;
-            var importer = new ReferenceLineImporter
-            {
-                ProgressChanged = (description, step, steps) =>
-                {
-                    Assert.AreEqual(expectedProgressMessages[progressChangedCount].Text, description);
-                    Assert.AreEqual(expectedProgressMessages[progressChangedCount].CurrentStep, step);
-                    Assert.AreEqual(expectedProgressMessages[progressChangedCount].MaxNrOfSteps, steps);
-                    progressChangedCount++;
-                }
-            };
-
             DialogBoxHandler = (name, wnd) =>
             {
                 importer.Cancel();
@@ -444,10 +429,10 @@
             };
 
             // Call
-            importer.Import(referenceLineContext, path);
+            Action call = () => importer.Import(referenceLineContext, path);
 
             // Assert
-            Assert.AreEqual(expectedProgressMessages.Length, progressChangedCount);
+            TestHelper.AssertLogMessageIsGenerated(call, "Referentielijn importeren afgebroken. Geen data ingelezen.", 1);
             mocks.VerifyAll();
         }