// Perform the binary operation.
public override bool TryBinaryOperation(
BinaryOperationBinder binder, object arg, out object result)
{
// The Textual property contains the textual representaion
// of two numbers, in addition to the name
// of the binary operation.
string resultTextual =
dictionary["Textual"].ToString() + " "
+ binder.Operation + " " +
((DynamicNumber)arg).dictionary["Textual"].ToString();
int resultNumeric;
// Checking what type of operation is being performed.
switch (binder.Operation)
{
// Proccessing mathematical addition (a + b).
case ExpressionType.Add:
resultNumeric =
(int)dictionary["Numeric"] +
(int)((DynamicNumber)arg).dictionary["Numeric"];
break;
// Processing mathematical substraction (a - b).
case ExpressionType.Subtract:
resultNumeric =
(int)dictionary["Numeric"] -
(int)((DynamicNumber)arg).dictionary["Numeric"];
break;
// In case of any other binary operation,
// print out the type of operation and return false,
// which means that the language should determine
// what to do.
// (Usually the language just throws an exception.)
default:
Console.WriteLine(
binder.Operation +
": This binary operation is not implemented");
result = null;
return(false);
}
dynamic finalResult = new DynamicNumber();
finalResult.Textual = resultTextual;
finalResult.Numeric = resultNumeric;
result = finalResult;
return(true);
}
static void Test(string[] args)
{
// Creating the first dynamic number.
dynamic firstNumber = new DynamicNumber();
// Creating properties and setting their values
// for the first dynamic number.
// The TrySetMember method is called.
firstNumber.Textual = "One";
firstNumber.Numeric = 1;
// Printing out properties. The TryGetMember method is called.
Console.WriteLine(
firstNumber.Textual + " " + firstNumber.Numeric);
// Creating the second dynamic number.
dynamic secondNumber = new DynamicNumber();
secondNumber.Textual = "Two";
secondNumber.Numeric = 2;
Console.WriteLine(
secondNumber.Textual + " " + secondNumber.Numeric);
dynamic resultNumber = new DynamicNumber();
// Adding two numbers. The TryBinaryOperation is called.
resultNumber = firstNumber + secondNumber;
Console.WriteLine(
resultNumber.Textual + " " + resultNumber.Numeric);
// Subtracting two numbers. TryBinaryOperation is called.
resultNumber = firstNumber - secondNumber;
Console.WriteLine(
resultNumber.Textual + " " + resultNumber.Numeric);
// The following statement produces a run-time exception
// because the multiplication operation is not implemented.
// resultNumber = firstNumber * secondNumber;
}