IDslCompilerContextSet Method

void Set(
	string key,
	Object value
)

In general, a context variable can accept anything. However, for storing data objects, we recommend using Ref(String, String) for more efficiency and better overall performance.
You can also declare a variable and bind it to a Form Component using data binding:

// Assuming a workflow has 2 activities like below:
// Activity 1:
ctx.Set("Confirmed", true);
ctx.Set("ConfirmedOption", 5);
// Activity 2:
if (ctx.Get<bool>("Confirmed"))
    DoSomething(ctx.Get<int>("ConfirmedOption"));