Custom inspector for System class (TimeSpan)

I’m making use of System.TimeSpan in a couple of places, and I want these to be editable in the inspector. What’s the best way of going about this? I tried the following but it doesn’t work as UnityEngine.Object cannot be converted to System.Timespan…

[CustomEditor(typeof(TimeSpan))]
public class TimeSpanInspector : Editor
{
	private TimeSpan _ts;

	public void OnEnable()
	{
		_ts = (TimeSpan)target;
	}

	public override void OnInspectorGUI()
	{
		GUILayout.BeginHorizontal();
		int hours = EditorGUILayout.IntField(_ts.Hours, GUILayout.Width(50));
		GUILayout.EndHorizontal();

		_ts = new TimeSpan(hours, 0, 0);
	}
}

The easiest way to accomplish this would be to write a MonoBehaviour wrapper for TimeSpan and then have references to that wrapper. This does impose some limitations, namely, that you need to attach your TimeSpan-wrapper to a GameObject. To inspect this object, you firstly need a custom inspector (or a propery drawer). Secondly you need to use the getters and setters in the wrapper instead of directly accessing the TimeSpan when inspecting.

For those who do not know what a wrapper is, it’s basically a class that is ‘wrapped’ around another class, providing suitable implementations for the current platform. The TimeSpan wrapper could look something like this:

public class TimeSpanWrapper : MonoBehavior{
    private TimeSpan timeSpan;

    //use this to create new TimeSpanWrappers
    public static TimeSpanWrapper Create(GameObject go, int hours, int minutes, int seconds){
        TimeSpanWrapper tsw = go.AddComponent<TimeSpanWrapper>();
        tsw.Init(hours, minutes, seconds);
        return tsw;
    }

     public void Init(int hours, int minutes, int seconds){
         timeSpan = new TimeSpan(hours, minutes, seconds);
         //this is actually the constructor where we set
         //the values for the private TimeSpan.
     }

     //Here goes methods you need from TimeSpan. If
     //TimeSpan had a GetHours method, we would create a
     //method as follows:
     
     public int GetHours(){ return TimeSpan.GetHours(); }
}

Everything in the inspector must derive from UNityEngine.Object (that is what the error means).
To get around this you’ll need to create a new class that has a TimeSpan variable on it.

ie

public class UnityTimeSpan : MonoBehaviour
{
    public TimeSpan span;
}

Then you’ll have to use UnityTimeSpan instead of TimeSpan and you can create an editor for UnityTimeSpan.