public static IEnumerable <DrawObject> GetAllVisibleDrawObjects(this ICanvasDataContext canvasDataContext)
{
if (canvasDataContext == null)
{
throw new ArgumentNullException(nameof(canvasDataContext));
}
return(canvasDataContext.GetAllDrawObjects()?.Where(p => p.IsVisible));
}
/// <summary>
/// 获取所有指定类型的绘制对象;
/// </summary>
/// <typeparam name="TDrawObject"></typeparam>
/// <param name="canvasDataContext"></param>
/// <returns></returns>
public static IEnumerable <TDrawObject> GetAllDrawObjects <TDrawObject>(this ICanvasDataContext canvasDataContext) where TDrawObject : DrawObject
{
if (canvasDataContext == null)
{
throw new ArgumentNullException(nameof(canvasDataContext));
}
return(canvasDataContext.GetAllDrawObjects()?.OfType <TDrawObject>());
}