AutoAttribute Class

Properties or fields with this attribute are candidates for automatic binding.

If the type of the field is ModuleEmulator then the field is assigned a reference to the ModuleEmulator.
If the type is the user script module emulator type (that was passed in to the ModuleEmulator.Install method) then a reference to the user module emulator object is assigned to the field.

class MyDigitalModule {
    class Channel {
        [Auto] MyDigitalModule myModule;           // assigned the instance of this MyDigitalModule
    }

    [Auto] ModuleEmulator moduleEmulator;          // assigned the associated ModuleEmulator instance
    [Auto] Channel        Ch00;                    // automatically instantiated
}

Other fields (other than module emulator references) marked with [Auto] will be auto-instatiated if they contain a null reference after their class constructor has returned. In the example above Ch00 is not assigned a value by the MyDigitalModule constructor, and therefore [Auto] will automatically instantiate a Channel and assign the reference to Ch00.

When a field is auto-instantiated, a suitable constructor is searched for. Constructor parameters can include

public Channel(ModuleEmulator moduleEmulator,  // the associated ModuleEmulator instance
               MyDigitalModule myModule,       // the instance of this MyDigitalModule
               int channelId) {                // the index of this channel in a channel array
}

[Auto, TagName(ArrayWidth = 16, Name = "Ch{i:00}")]
protected readonly Channel[] channels = new Channel[16];

Order of instantiation of fields in the module emulator is well defined. Instantiation is performed strictly in the order in which [Auto] fields are encountered. If a field is itself an [Auto] class field, then its sub-properties are traversed before continuing to the next field. (Ie depth-first.) Instances of SomeLogic (in the example below) are auto-instantiated. Their order of instantiation is indicated in the example.

class MyDigitalModule {
    class SomeLogic { }

    class ChannelBaseClass {
        [Auto] SomeLogic logic1;                   // instantiated in the order they appear in the script
        [Auto] SomeLogic logic2;
    }

    class Channel : ChannelBaseClass {             // ChannelBaseClass fields instantiated first
        [Auto] SomeLogic logic3;
        [Auto] SomeLogic logic4;
    }

    [Auto] Channel Ch00;
}

By default, the order of execution of events (ComputeInputs, ProcessOutputs, etc) follows the same order as the order of instantiation. This can be overridden using the ExecutionOrderAttribute.

Reference