UpdateDemo | 应用内更新demo，支持断点续传，缓存清理

You could always use a Ref return

Starting with C# 7.0, C# supports reference return values (ref returns). A reference return value allows a method to return a reference to a variable, rather than a value, back to a caller. The caller can then choose to treat the returned variable as if it were returned by value or by reference. The caller can create a new variable that is itself a reference to the returned value, called a ref local.

Limitations

There are some restrictions on the expression that a method can return as a reference return value. Restrictions include:

• The return value must have a lifetime that extends beyond the execution of the method. In other words, it cannot be a local variable in the method that returns it. It can be an instance or static field of a class, or it can be an argument passed to the method. Attempting to return a local variable generates compiler error CS8168, "Cannot return local 'obj' by reference because it is not a ref local."

• The return value cannot be the literal null. Returning null generates compiler error CS8156, "An expression cannot be used in this context because it may not be returned by reference."

• A method with a ref return can return an alias to a variable whose value is currently the null (uninstantiated) value or a nullable type for a value type.

• The return value cannot be a constant, an enumeration member, the by-value return value from a property, or a method of a class or struct. Violating this rule generates compiler error CS8156, "An expression cannot be used in this context because it may not be returned by reference."

A really contrived example and not what i recommend, however it does achieve your goals (academically)

Example

I had a similar scenario and solved it by letting the current controller double as the controller for mdDialog. Here's the code I used:

You have to declare the demos variable as class variable so if you change the code like this, it should be ok