Add MinItems and MaxItems properties to ListDrawerSettingsAttribute

[Dan Vicarel]

It would be really helpful if one could specify the min and max number of elements allowed for a list. To make this general, I would think ListDrawerSettingsAttribute should expose new MinItems and MaxItems properties. I tried making this work with the current APIs (v3.0.12.0 on Windows 11 Pro) via CustomAddFunction and CustomRemoveFunction, but these properties are poorly documented so I wasn’t really sure how to use them, and I think I’m running into issue #437 anyway.

[Antonio Rafael Antunes Miranda]

If you’re using the TableList attribute, then yes, you won’t be able to use the ListDrawerSettings attribute since they’re not compatible.

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The CustomAddFunction and CustomRemoveElementFunction / CustomRemoveIndexFunction work like this:

• Inside the ListDrawerSettings attribute you provide the name of the respective function as a string.

• When Odin detects that you want to add or remove an element, it will call the respective function and pass it the arguments that you’ve specified. Valid arguments are:

  • CustomAddFunction: InspectorProperty property, List<T> list where T will be the type your list holds.
  • CustomRemoveIndexFunction: InspectorProperty property, List<T> list, int index where T will be the type your list holds.
  • CustomRemoveElementFunction: InspectorProperty property, List<T> list, T elementToBeRemoved where T will be the type your list holds.

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Example:

// Remove by Index
[ListDrawerSettings(CustomAddFunction = "CustomAdd", CustomRemoveIndexFunction = "CustomRemoveIndex")]
public List<string> SomeListOfStrings1 = new List<string>();

// Remove by element
[ListDrawerSettings(CustomAddFunction = "CustomAdd", CustomRemoveElementFunction = "CustomRemoveElement")]
public List<string> SomeListOfStrings2 = new List<string>();

// We don't need the InspectorProperty so we don't add it to the parameter list.
private void CustomAdd(List<string> list)
{
    list.Add("I was added by a custom add function.");
}

//We don't need the InspectorProperty so we don't add it to the parameter list
private void CustomRemoveIndex(List<string> list, int index)
{
    list.RemoveAt(index);
}

//We don't need the InspectorProperty so we don't add it to the parameter list
private void CustomRemoveElement(List<string> list, string elementToBeRemoved)
{
    list.Remove(elementToBeRemoved);
}

‌

[Dan Vicarel]

Antonio, thanks for description, that was very helpful! All of this seems like information that should be in the docs….maybe I missed it. Is there a page other than this one that already had this info?

[Antonio Rafael Antunes Miranda]

The documentation around resolvers is a bit lacking right now, but there are a few things that can help with them.

• You always have access to the InspectorProperty and the value so those are fixed. That information is listed here: https://odininspector.com/tutorials/value-and-action-resolvers/named-values
• You can define a parameter that you know/think is not part of the named values and then you will get an error message in the inspector that shows you all possible values and their types.

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I understand that this is by no means perfect, but other things kind of took the attention If you have questions about something then the discord is a great place to ask as it’s usuall easier to see and answer there.

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I’ve written down all your suggestions from this and the other ticket and I’m going to write down something for the docs that will then hopefully be available there.