Unity3D mouse to canvas position (dragging item on canvas)

drag.cs

using UnityEngine;

public class MouseDrag : MonoBehaviour
{
	void Update()
	{
		if (Input.GetMouseButton(0))
		{
			var canvas = transform.root.GetComponent<Canvas>();
			var canvasRect = canvas.GetComponent<RectTransform>();
			if (RectTransformUtility.ScreenPointToLocalPointInRectangle(
				canvasRect,
				Input.mousePosition,
				canvas.renderMode == RenderMode.ScreenSpaceOverlay ? null : canvas.worldCamera,
				out Vector2 mousePosInCanvasSpace))
			{
				var selfRect = GetComponent<RectTransform>();
				selfRect.localPosition = mousePosInCanvasSpace;
			}
		}
	}
}