Index: Riskeer/Common/src/Riskeer.Common.Forms/ChangeHandlers/ClearCalculationOutputChangeHandlerBase.cs
===================================================================
diff -u
--- Riskeer/Common/src/Riskeer.Common.Forms/ChangeHandlers/ClearCalculationOutputChangeHandlerBase.cs	(revision 0)
+++ Riskeer/Common/src/Riskeer.Common.Forms/ChangeHandlers/ClearCalculationOutputChangeHandlerBase.cs	(revision 551adc15997614cd3df87522131fc90f4cd2484a)
@@ -0,0 +1,96 @@
+// Copyright (C) Stichting Deltares 2019. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using Core.Common.Base;
+using Core.Common.Gui.Commands;
+using Core.Common.Gui.Helpers;
+using Riskeer.Common.Data.Calculation;
+using Riskeer.Common.Forms.Properties;
+
+namespace Riskeer.Common.Forms.ChangeHandlers
+{
+    /// <summary>
+    /// Base class for handling clearing calculation output.
+    /// </summary>
+    public abstract class ClearCalculationOutputChangeHandlerBase : IClearCalculationOutputChangeHandler
+    {
+        private readonly IEnumerable<ICalculation> calculations;
+        private readonly IInquiryHelper inquiryHelper;
+
+        /// <summary>
+        /// Creates a new instance of <see cref="ClearCalculationOutputChangeHandlerBase"/>.
+        /// </summary>
+        /// <param name="calculations">The calculations to clear the output for.</param>
+        /// <param name="inquiryHelper">Object responsible for inquiring confirmation.</param>
+        /// <param name="viewCommands"></param>
+        /// <exception cref="ArgumentNullException">Thrown when any parameter is <c>null</c>.</exception>
+        protected ClearCalculationOutputChangeHandlerBase(IEnumerable<ICalculation> calculations, IInquiryHelper inquiryHelper, IViewCommands viewCommands)
+        {
+            if (calculations == null)
+            {
+                throw new ArgumentNullException(nameof(calculations));
+            }
+
+            if (inquiryHelper == null)
+            {
+                throw new ArgumentNullException(nameof(inquiryHelper));
+            }
+
+            if (viewCommands == null)
+            {
+                throw new ArgumentNullException(nameof(viewCommands));
+            }
+
+            this.calculations = calculations;
+            this.inquiryHelper = inquiryHelper;
+            ViewCommands = viewCommands;
+        }
+        
+        /// <summary>
+        /// Gets the <see cref="IViewCommands"/>.
+        /// </summary>
+        protected IViewCommands ViewCommands { get; }
+
+        public bool InquireConfirmation()
+        {
+            return inquiryHelper.InquireContinuation(Resources.FailureMechanism_ContextMenuStrip_Are_you_sure_clear_all_output);
+        }
+
+        public IEnumerable<IObservable> ClearCalculations()
+        {
+            DoPreUpdateActions();
+
+            foreach (ICalculation calculation in calculations)
+            {
+                calculation.ClearOutput();
+            }
+
+            return calculations;
+        }
+
+        /// <summary>
+        /// Performs pre-update actions
+        /// </summary>
+        protected abstract void DoPreUpdateActions();
+    }
+}
\ No newline at end of file
Index: Riskeer/Common/src/Riskeer.Common.Forms/ChangeHandlers/IClearCalculationOutputChangeHandler.cs
===================================================================
diff -u
--- Riskeer/Common/src/Riskeer.Common.Forms/ChangeHandlers/IClearCalculationOutputChangeHandler.cs	(revision 0)
+++ Riskeer/Common/src/Riskeer.Common.Forms/ChangeHandlers/IClearCalculationOutputChangeHandler.cs	(revision 551adc15997614cd3df87522131fc90f4cd2484a)
@@ -0,0 +1,44 @@
+// Copyright (C) Stichting Deltares 2019. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System.Collections.Generic;
+using Core.Common.Base;
+
+namespace Riskeer.Common.Forms.ChangeHandlers
+{
+    /// <summary>
+    /// Interface for handling clearing calculation output.
+    /// </summary>
+    public interface IClearCalculationOutputChangeHandler
+    {
+        /// <summary>
+        /// Gets confirmation for clearing the illustration points.
+        /// </summary>
+        /// <returns><c>true</c> when confirmation is given, <c>false</c> otherwise.</returns>
+        bool InquireConfirmation();
+
+        /// <summary>
+        /// Clears all illustration points and returns the affected objects.
+        /// </summary>
+        /// <returns>The affected objects by the operation.</returns>
+        IEnumerable<IObservable> ClearCalculations();
+    }
+}
\ No newline at end of file
Index: Riskeer/Common/test/Riskeer.Common.Forms.Test/ChangeHandlers/ClearCalculationOutputChangeHandlerBaseTest.cs
===================================================================
diff -u
--- Riskeer/Common/test/Riskeer.Common.Forms.Test/ChangeHandlers/ClearCalculationOutputChangeHandlerBaseTest.cs	(revision 0)
+++ Riskeer/Common/test/Riskeer.Common.Forms.Test/ChangeHandlers/ClearCalculationOutputChangeHandlerBaseTest.cs	(revision 551adc15997614cd3df87522131fc90f4cd2484a)
@@ -0,0 +1,177 @@
+// Copyright (C) Stichting Deltares 2019. All rights reserved.
+//
+// This file is part of Riskeer.
+//
+// Riskeer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+//
+// All names, logos, and references to "Deltares" are registered trademarks of
+// Stichting Deltares and remain full property of Stichting Deltares at all times.
+// All rights reserved.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Core.Common.Base;
+using Core.Common.Gui.Commands;
+using Core.Common.Gui.Helpers;
+using NUnit.Framework;
+using Rhino.Mocks;
+using Riskeer.Common.Data.Calculation;
+using Riskeer.Common.Forms.ChangeHandlers;
+
+namespace Riskeer.Common.Forms.Test.ChangeHandlers
+{
+    [TestFixture]
+    public class ClearCalculationOutputChangeHandlerBaseTest
+    {
+        [Test]
+        public void Constructor_CalculationsNull_ThrowsArgumentNullException()
+        {
+            // Setup
+                var mocks = new MockRepository();
+                var inquiryHelper = mocks.Stub<IInquiryHelper>();
+                var viewCommands = mocks.Stub<IViewCommands>();
+                mocks.ReplayAll();
+            
+            // Call
+            void Call() => new TestClearCalculationOutputChangeHandler(null, inquiryHelper, viewCommands);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(Call);
+            Assert.AreEqual("calculations", exception.ParamName);
+            mocks.VerifyAll();
+        }
+
+        [Test]
+        public void Constructor_InquiryHelperNull_ThrowsArgumentNullException()
+        {
+            // Setup
+            var mocks = new MockRepository();
+            var viewCommands = mocks.Stub<IViewCommands>();
+            mocks.ReplayAll();
+            
+            // Call
+            void Call() => new TestClearCalculationOutputChangeHandler(Enumerable.Empty<ICalculation>(), null, viewCommands);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(Call);
+            Assert.AreEqual("inquiryHelper", exception.ParamName);
+            mocks.VerifyAll();
+        }
+
+        [Test]
+        public void Constructor_ViewCommandsNull_ThrowsArgumentNullException()
+        {
+            // Setup
+            var mocks = new MockRepository();
+            var inquiryHelper = mocks.Stub<IInquiryHelper>();
+            mocks.ReplayAll();
+
+            // Call
+            void Call() => new TestClearCalculationOutputChangeHandler(Enumerable.Empty<ICalculation>(), inquiryHelper, null);
+
+            // Assert
+            var exception = Assert.Throws<ArgumentNullException>(Call);
+            Assert.AreEqual("viewCommands", exception.ParamName);
+            mocks.VerifyAll();
+        }
+
+        [Test]
+        public void Constructor_ExpectedValues()
+        {
+            // Setup
+            var mocks = new MockRepository();
+            var inquiryHelper = mocks.Stub<IInquiryHelper>();
+            var viewCommands = mocks.Stub<IViewCommands>();
+            mocks.ReplayAll();
+
+            // Call
+            var changeHandler = new TestClearCalculationOutputChangeHandler(Enumerable.Empty<ICalculation>(), inquiryHelper, viewCommands);
+
+            // Assert
+            Assert.IsInstanceOf<IClearCalculationOutputChangeHandler>(changeHandler);
+            mocks.VerifyAll();
+        }
+
+        [Test]
+        [TestCase(true)]
+        [TestCase(false)]
+        public void InquireConfirmation_Always_DisplaysInquiryAndReturnsConfirmation(bool expectedConfirmation)
+        {
+            // Setup
+            const string expectedInquiry = "Weet u zeker dat u alle uitvoer wilt wissen?";
+            
+            var mocks = new MockRepository();
+            var inquiryHelper = mocks.StrictMock<IInquiryHelper>();
+            inquiryHelper.Expect(h => h.InquireContinuation(expectedInquiry)).Return(expectedConfirmation);
+            var viewCommands = mocks.Stub<IViewCommands>();
+            mocks.ReplayAll();
+
+            var changeHandler = new TestClearCalculationOutputChangeHandler(Enumerable.Empty<ICalculation>(), inquiryHelper, viewCommands);
+            
+            // Call
+            bool confirmation = changeHandler.InquireConfirmation();
+            
+            // Assert
+            Assert.AreEqual(expectedConfirmation, confirmation);
+            mocks.VerifyAll();
+        }
+
+        [Test]
+        public void ClearCalculations_Always_ExecutesPreUpdateActionsAndClearsOutput()
+        {
+            // Setup
+            var mocks = new MockRepository();
+            var inquiryHelper = mocks.Stub<IInquiryHelper>();
+            var viewCommands = mocks.Stub<IViewCommands>();
+            var calculation1 = mocks.StrictMock<ICalculation>();
+            calculation1.Expect(c => c.ClearOutput());
+            var calculation2 = mocks.StrictMock<ICalculation>();
+            calculation2.Expect(c => c.ClearOutput());
+            mocks.ReplayAll();
+
+            ICalculation[] calculations = 
+            {
+                calculation1,
+                calculation2
+            };
+            
+            var changeHandler = new TestClearCalculationOutputChangeHandler(calculations, inquiryHelper, viewCommands);
+            
+            // Precondition
+            Assert.IsFalse(changeHandler.DoPreUpdateActionsExecuted);
+
+            // Call
+            IEnumerable<IObservable> affectedCalculations = changeHandler.ClearCalculations();
+            
+            // Assert
+            Assert.IsTrue(changeHandler.DoPreUpdateActionsExecuted);
+            CollectionAssert.AreEqual(calculations, affectedCalculations);
+            mocks.VerifyAll();
+        }
+        
+        private class TestClearCalculationOutputChangeHandler : ClearCalculationOutputChangeHandlerBase
+        {
+            public TestClearCalculationOutputChangeHandler(IEnumerable<ICalculation> calculations, IInquiryHelper inquiryHelper, IViewCommands viewCommands) 
+                : base(calculations, inquiryHelper, viewCommands) {}
+            
+            protected override void DoPreUpdateActions()
+            {
+                DoPreUpdateActionsExecuted = true;
+            }
+
+            public bool DoPreUpdateActionsExecuted { get; private set; }
+        }   
+    }
+}
\ No newline at end of file