Question

I need to convert a bound (UnityEngine.Component) List to a generic (T) List, is this possible? how?

I’m using Unity and C#, but I would like to know in general how one would do this.

        List<Component> compList = new List<Component>();
        foreach(GameObject obj in objects)   // objects is List<GameObject>
        {
            var retrievedComp = obj.GetComponent(typeof(T));
            if(retrievedComp != null)
                compList.Add(retrievedComp);
        }

        List<T> newList = new List<T>(compList as IEnumerable<T>); // ERROR HERE

        foreach(T n in newList)
            Debug.Log(n);

thanks!

I assume that is the issue, I’m getting this runtime error…

ArgumentNullException: Argument cannot be null.
Parameter name: collection
System.Collections.Generic.List`1[TestPopulateClass].CheckCollection (IEnumerable`1 collection)
System.Collections.Generic.List`1[TestPopulateClass]..ctor (IEnumerable`1 collection)
DoPopulate.AddObjectsToList[TestPopulate] (System.Reflection.FieldInfo target) (at Assets/Editor/ListPopulate/DoPopulate.cs:201)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture)
Rethrow as TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters)
DoPopulate.OnGUI () (at Assets/Editor/ListPopulate/DoPopulate.cs:150)
System.Reflection.MonoMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture)

Answer 1

Have you tried

    List<T> newList = compList.OfType<T>().Select(x=>x).ToList()