ConstraintSystem.AddConstraints Method

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Returns a value that indicates whether all constraint functions added to a model are valid.

Namespace:  Microsoft.SolverFoundation.Solvers
Assembly:  Microsoft.Solver.Foundation (in Microsoft.Solver.Foundation.dll)


Public Function AddConstraints ( _
    ParamArray constraints As CspTerm() _
) As Boolean
public bool AddConstraints(
    params CspTerm[] constraints
bool AddConstraints(
    ... array<CspTerm^>^ constraints
member AddConstraints : 
        constraints:CspTerm[] -> bool 
public function AddConstraints(
    ... constraints : CspTerm[]
) : boolean


Return Value

Type: System.Boolean
true if all constraint functions added to a model are valid; otherwise, false.


Constraint functions must return a Boolean value. Other functions are considered to be interior nodes in expression trees and provide inputs to constraint functions.


The following code demonstrates how to use the ConstraintSystem object to solve the Zebra logic puzzle. For more examples, see Samples for Solver Foundation.

delegate CspTerm NamedTerm(string name);

public static void Zebra() {
  ConstraintSystem S = ConstraintSystem.CreateSolver();
  var termList = new List<KeyValuePair<CspTerm, string>>();

  NamedTerm House = delegate(string name) {
    CspTerm x = S.CreateVariable(S.CreateIntegerInterval(1, 5), name);
    termList.Add(new KeyValuePair<CspTerm, string>(x, name));
    return x;

  CspTerm English = House("English"), Spanish = House("Spanish"),
    Japanese = House("Japanese"), Italian = House("Italian"),
    Norwegian = House("Norwegian");
  CspTerm red = House("red"), green = House("green"),
    white = House("white"),
    blue = House("blue"), yellow = House("yellow");
  CspTerm dog = House("dog"), snails = House("snails"),
    fox = House("fox"),
    horse = House("horse"), zebra = House("zebra");
  CspTerm painter = House("painter"), sculptor = House("sculptor"),
    diplomat = House("diplomat"), violinist = House("violinist"),
    doctor = House("doctor");
  CspTerm tea = House("tea"), coffee = House("coffee"),
    milk = House("milk"),
    juice = House("juice"), water = House("water");

    S.Unequal(English, Spanish, Japanese, Italian, Norwegian),
    S.Unequal(red, green, white, blue, yellow),
    S.Unequal(dog, snails, fox, horse, zebra),
    S.Unequal(painter, sculptor, diplomat, violinist, doctor),
    S.Unequal(tea, coffee, milk, juice, water),
    S.Equal(English, red),
    S.Equal(Spanish, dog),
    S.Equal(Japanese, painter),
    S.Equal(Italian, tea),
    S.Equal(1, Norwegian),
    S.Equal(green, coffee),
    S.Equal(1, green - white),
    S.Equal(sculptor, snails),
    S.Equal(diplomat, yellow),
    S.Equal(3, milk),
    S.Equal(1, S.Abs(Norwegian - blue)),
    S.Equal(violinist, juice),
    S.Equal(1, S.Abs(fox - doctor)),
    S.Equal(1, S.Abs(horse - diplomat))
  bool unsolved = true;
  ConstraintSolverSolution soln = S.Solve();

  while (soln.HasFoundSolution) {
    unsolved = false;
    StringBuilder[] houses = new StringBuilder[5];
    for (int i = 0; i < 5; i++)
      houses[i] = new StringBuilder(i.ToString());
    foreach (KeyValuePair<CspTerm, string> kvp in termList) {
      string item = kvp.Value;
      object house;
      if (!soln.TryGetValue(kvp.Key, out house))
        throw new InvalidProgramException(
                    "can't find a Term in the solution: " + item);
      houses[(int)house - 1].Append(", ");
      houses[(int)house - 1].Append(item);
    foreach (StringBuilder house in houses) {
  if (unsolved)
    System.Console.WriteLine("No solution found.");
"Expected: the Norwegian drinking water and the Japanese with the zebra.");

.NET Framework Security

See Also


ConstraintSystem Class

Microsoft.SolverFoundation.Solvers Namespace