C# 4 and .NET 4

add-in sample ❘ OC89
}
}
}
public override double Operate(Operation operation, double[] operand)
{
switch (operation.Name)
{
case "+":
return operand[0] + operand[1];
case "-":
return operand[0]—operand[1];
case "/":
return operand[0] / operand[1];
case "*":
return operand[0] * operand[1];
default:
throw new InvalidOperationException(
String.Format("invalid operation {0}", operation.Name));
}
}
code snippet CalcAddIn/Calculator.cs
Calculator host View
Let’s continue with the host view of the host side. Like the add-in view, the host view defines an abstract
class with methods similar to the contract. However, the methods defined here are invoked by the host
application.
Both the classes Calculator and Operation are abstract, as the members are implemented by the host
adapter. The classes here just need to define the interface to be used by the host application.
using System.Collections.Generic;
namespace Wrox.ProCSharp.MAF
{
public abstract class Calculator
{
public abstract IList GetOperations();
public abstract double Operate(Operation operation,
params double[] operand);
}
public abstract class Operation
{
public abstract string Name { get; }
public abstract int NumberOperands { get; }
}
}
Calculator host adapter
code snippet HostView/CalculatorHostView.cs
The host adapter assembly references the host view and the contract to map the view to the contract. The
class OperationContractToViewHostAdapter implements the members of the abstract Operation class.
The class CalculatorContractToViewHostAdapter implements the members of the abstract
Calculator class.
With OperationContractToViewHostAdapter, the reference to the contract is assigned in the constructor.
The adapter class also contains a ContractHandle instance that adds a lifetime reference to the contract,
so that the add-in stays loaded as long it is needed by the hosting application.
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