Using the Calculation Engine

The CalculationEngine allows you to create a network of expressions. The engine allows expressions to reference the results of other expressions in the engine, tracks dependencies, and recalculates in natural order.

// Create the calculation engine
CalculationEngine engine = new CalculationEngine();
ExpressionContext context = new ExpressionContext();
VariableCollection variables = context.Variables;

// Add some variables
variables.Add("x", 100);            
variables.Add("y", 200);

// Add an expression to the calculation engine as "a"
engine.Add("a", "x * 2", context);

// Add an expression to the engine as "b"
engine.Add("b", "y + 100", context);
            
// Add an expression at "c" that uses the results of "a" and "b"
engine.Add("c", "a + b", context);
            
// Get the value of "c"
int result = engine.GetResult<int>("c");

// Update a variable on the "a" expression            
variables["x"] = 200;

// Recalculate it
engine.Recalculate("a");

// Get the updated result
result = engine.GetResult<int>("c");