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| protected void Initialize(IQueryable<T> source, int index, int pageSize, int? totalCount)
{
//### argument checking
if (index < 0)
{
throw new ArgumentOutOfRangeException("PageIndex cannot be below 0.");
}
if (pageSize < 1)
{
throw new ArgumentOutOfRangeException("PageSize cannot be less than 1.");
}
//### set source to blank list if source is null to prevent exceptions
if (source == null)
{
source = new List<T>().AsQueryable();
}
//### set properties
if (!totalCount.HasValue)
{
TotalItemCount = source.Count();
}
PageSize = pageSize;
PageIndex = index;
if (TotalItemCount > 0)
{
PageCount = (int)Math.Ceiling(TotalItemCount / (double)PageSize);
}
else
{
PageCount = 0;
}
HasPreviousPage = (PageIndex > 0);
HasNextPage = (PageIndex < (PageCount - 1));
IsFirstPage = (PageIndex <= 0);
IsLastPage = (PageIndex >= (PageCount - 1));
//### add items to internal list
if (TotalItemCount > 0)
{
AddRange(source.Skip((index) * pageSize).Take(pageSize).ToList());
}
} |