Animating sprites

Animation.cs

public class Frame
{
    public Texture2D Texture;
    public Rectangle? TextureClip;
    public Vector2 LocalTextureTranslate;
    public Transform Hitbox;
}

public class FramesManager
{
    public string Id { get; private set; }
    public List<Frame> Frames;
    public float DeltaTimeFrame;
    public int CurrentFrameIndex;
    private float currentDeltaTime;

    public Frame CurrentFrame
    {
        get { return Frames[CurrentFrameIndex]; }
    }

    public FramesManager(string id, float deltaTimeFrame)
    {
        Id = id;
        DeltaTimeFrame = deltaTimeFrame;
        currentDeltaTime = 0;
        CurrentFrameIndex = 0;
    }

    public void Update()
    {
        currentDeltaTime += GameCore.DeltaTime;
        if (currentDeltaTime >= DeltaTimeFrame)
        {
            NextFrame();
            currentDeltaTime = 0;
        }
    }

    public void NextFrame()
    {
        if (CurrentFrameIndex + 1 >= Frames.Count)
        {
            CurrentFrameIndex = 0;
        }
        else
        {
            CurrentFrameIndex++;
        }
    }

}

public class Animation : Sprite
{
    private Dictionary<string, FramesManager> _animations;

    private FramesManager _currentAnimation;
    public FramesManager CurrentAnimation
    {
        get { return _currentAnimation; }
    }

    public string CurrentAnimationId
    {
        get
        {
            if (_currentAnimation.IsNull())
            {
                return string.Empty;
            }
            else
            {
                return _currentAnimation.Id;
            }
        }
    }

    private string _nextAnimation;

    public Animation(int zIndex = 0) : base(default(Texture2D), true, zIndex)
    {
        Active = true;
        _animations = new Dictionary<string, FramesManager>();
    }

    public override void Update()
    {
        base.Update();
        if (_nextAnimation != CurrentAnimationId)
        {
            _currentAnimation = _animations[_nextAnimation];
        }

        if (_currentAnimation.IsNotNull())
        {
            _currentAnimation.Update();
        }
    }

    public void AddAnimation(string id, FramesManager frames)
    {
        if (!_animations.ContainsKey(id))
        {
            _animations.Add(id, frames);
        }
    }

    public void AddAnimation(string id, float delta, params Frame[] frames)
    {
        if (!_animations.ContainsKey(id))
        {
            _animations.Add(id, new FramesManager(id, delta) { Frames = new List<Frame>(frames) });
        }
    }

    public void RemoveAnimation(string id)
    {
        if (_animations.ContainsKey(id) && _currentAnimation.Id != id)
        {
            _animations.Remove(id);
        }
    }

    public void ChangeAnimation(string id)
    {
        if (_animations.ContainsKey(id))
        {
            _nextAnimation = id;
        }
    }
    
    public void Draw()
    {
      spriteBatch.Draw(
                            _currentAnimation.CurrentFrame.Texture,
                            TexturePosition + drawable.TextureLocalTranslate,
                            _currentAnimation.CurrentFrame.TextureClip,
                            Color.White);
    }
}