How Do I Declare A Lambda in C#?

As a local variable:

Action<parameterTypes> lambdaName = (parameters) => {...};

As a property:

public delegateType lambdaName { get; set; }

As a method parameter:

void someMethodThatTakesALambda(delegateType lambdaName) {...}

As an argument to a method call:

someObject.someMethodThatTakesALambda ((parameters) => {...});

As a custom delegate definition:

public delegate returnType DelegateName(parameterTypes);
DelegateName lambdaName = (parameters) => {...};