diff --git a/examples/dotnet/ShiftSchedulingSat.cs b/examples/dotnet/ShiftSchedulingSat.cs
index edf0926e6b..e1d5c7722c 100644
--- a/examples/dotnet/ShiftSchedulingSat.cs
+++ b/examples/dotnet/ShiftSchedulingSat.cs
@@ -546,25 +546,3 @@ public class ShiftSchedulingSat
     }
 }
 
-public class ObjectiveSolutionPrinter : CpSolverSolutionCallback
-{
-    private DateTime _startTime;
-    private int _solutionCount;
-
-    public ObjectiveSolutionPrinter()
-    {
-        _startTime = DateTime.Now;
-    }
-
-    public override void OnSolutionCallback()
-    {
-        var currentTime = DateTime.Now;
-        var objective = ObjectiveValue();
-        var objectiveBound = BestObjectiveBound();
-        var time = currentTime - _startTime;
-
-        Console.WriteLine($"Solution {_solutionCount}, time = {time.TotalSeconds} s, objective = [{objectiveBound}, {objective}]");
-
-        _solutionCount++;
-    }
-}
diff --git a/makefiles/Makefile.dotnet.mk b/makefiles/Makefile.dotnet.mk
index a0da48d8c7..92f282d114 100644
--- a/makefiles/Makefile.dotnet.mk
+++ b/makefiles/Makefile.dotnet.mk
@@ -327,6 +327,7 @@ $(DOTNET_ORTOOLS_NATIVE_NUPKG): \
  $(SRC_DIR)/ortools/sat/csharp/CpSolver.cs \
  $(SRC_DIR)/ortools/sat/csharp/IntegerExpressions.cs \
  $(SRC_DIR)/ortools/sat/csharp/IntervalVariables.cs \
+ $(SRC_DIR)/ortools/sat/csharp/SearchHelpers.cs \
  $(SRC_DIR)/ortools/util/csharp/NestedArrayHelper.cs \
  $(SRC_DIR)/ortools/util/csharp/ProtoHelper.cs \
  $(GEN_DIR)/ortools/constraint_solver/SearchLimit.pb.cs \
diff --git a/ortools/sat/csharp/CpSolver.cs b/ortools/sat/csharp/CpSolver.cs
index 48e93758ca..b055430a99 100644
--- a/ortools/sat/csharp/CpSolver.cs
+++ b/ortools/sat/csharp/CpSolver.cs
@@ -15,80 +15,7 @@ using System;
 using System.Collections.Generic;
 
 namespace Google.OrTools.Sat
-{
-
-  public class CpSolverSolutionCallback : SolutionCallback
-  {
-    public long Value(IntegerExpression e)
-    {
-      List<IntegerExpression> exprs = new List<IntegerExpression>();
-      List<long> coeffs = new List<long>();
-      exprs.Add(e);
-      coeffs.Add(1L);
-      long constant = 0;
-
-      while (exprs.Count > 0)
-      {
-        IntegerExpression expr = exprs[0];
-        exprs.RemoveAt(0);
-        long coeff = coeffs[0];
-        coeffs.RemoveAt(0);
-        if (coeff == 0) continue;
-
-        if (expr is ProductCst)
-        {
-          ProductCst p = (ProductCst)expr;
-          if (p.Coeff != 0)
-          {
-            exprs.Add(p.Expr);
-            coeffs.Add(p.Coeff * coeff);
-          }
-        }
-        else if (expr is SumArray)
-        {
-          SumArray a = (SumArray)expr;
-          constant += coeff * a.Constant;
-          foreach (IntegerExpression sub in a.Expressions)
-          {
-            exprs.Add(sub);
-            coeffs.Add(coeff);
-          }
-        }
-        else if (expr is IntVar)
-        {
-          int index = expr.Index;
-          long value = SolutionIntegerValue(index);
-          constant += coeff * value;
-        }
-        else if (expr is NotBooleanVariable)
-        {
-          throw new ArgumentException(
-              "Cannot evaluate a literal in an integer expression.");
-        }
-        else
-        {
-          throw new ArgumentException("Cannot evaluate '" + expr.ToString() +
-                                      "' in an integer expression");
-        }
-      }
-      return constant;
-    }
-
-    public Boolean BooleanValue(ILiteral literal)
-    {
-      if (literal is IntVar || literal is NotBooleanVariable)
-      {
-        int index = literal.GetIndex();
-        return SolutionBooleanValue(index);
-      }
-      else
-      {
-        throw new ArgumentException("Cannot evaluate '" + literal.ToString() +
-                                    "' as a boolean literal");
-      }
-    }
-  }
-
+{ 
   public class CpSolver
   {
 
diff --git a/ortools/sat/csharp/SearchHelpers.cs b/ortools/sat/csharp/SearchHelpers.cs
new file mode 100644
index 0000000000..1705bb7d7a
--- /dev/null
+++ b/ortools/sat/csharp/SearchHelpers.cs
@@ -0,0 +1,119 @@
+// Copyright 2010-2018 Google LLC
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using System;
+using System.Collections.Generic;
+
+namespace Google.OrTools.Sat
+{
+
+  public class CpSolverSolutionCallback : SolutionCallback
+  {
+    public long Value(IntegerExpression e)
+    {
+      List<IntegerExpression> exprs = new List<IntegerExpression>();
+      List<long> coeffs = new List<long>();
+      exprs.Add(e);
+      coeffs.Add(1L);
+      long constant = 0;
+
+      while (exprs.Count > 0)
+      {
+        IntegerExpression expr = exprs[0];
+        exprs.RemoveAt(0);
+        long coeff = coeffs[0];
+        coeffs.RemoveAt(0);
+        if (coeff == 0) continue;
+
+        if (expr is ProductCst)
+        {
+          ProductCst p = (ProductCst)expr;
+          if (p.Coeff != 0)
+          {
+            exprs.Add(p.Expr);
+            coeffs.Add(p.Coeff * coeff);
+          }
+        }
+        else if (expr is SumArray)
+        {
+          SumArray a = (SumArray)expr;
+          constant += coeff * a.Constant;
+          foreach (IntegerExpression sub in a.Expressions)
+          {
+            exprs.Add(sub);
+            coeffs.Add(coeff);
+          }
+        }
+        else if (expr is IntVar)
+        {
+          int index = expr.Index;
+          long value = SolutionIntegerValue(index);
+          constant += coeff * value;
+        }
+        else if (expr is NotBooleanVariable)
+        {
+          throw new ArgumentException(
+              "Cannot evaluate a literal in an integer expression.");
+        }
+        else
+        {
+          throw new ArgumentException("Cannot evaluate '" + expr.ToString() +
+                                      "' in an integer expression");
+        }
+      }
+      return constant;
+    }
+
+    public Boolean BooleanValue(ILiteral literal)
+    {
+      if (literal is IntVar || literal is NotBooleanVariable)
+      {
+        int index = literal.GetIndex();
+        return SolutionBooleanValue(index);
+      }
+      else
+      {
+        throw new ArgumentException("Cannot evaluate '" + literal.ToString() +
+                                    "' as a boolean literal");
+      }
+    }
+  }
+
+public class ObjectiveSolutionPrinter : CpSolverSolutionCallback
+{
+    private DateTime _startTime;
+    private int _solutionCount;
+
+    public ObjectiveSolutionPrinter()
+    {
+        _startTime = DateTime.Now;
+    }
+
+    public override void OnSolutionCallback()
+    {
+        var currentTime = DateTime.Now;
+        var objective = ObjectiveValue();
+        var objectiveBound = BestObjectiveBound();
+        var objLb = Math.Min(objective, objectiveBound);
+        var objUb = Math.Max(objective, objectiveBound);
+        var time = currentTime - _startTime;
+
+        Console.WriteLine(value: $"Solution {_solutionCount}, time = {time.TotalSeconds} s, objective = [{objLb}, {objUb}]");
+
+        _solutionCount++;
+    }
+
+    public int solutionCount() => _solutionCount;
+}
+
+}  // namespace Google.OrTools.Sat