/// <summary>
/// 新建内容页
/// </summary>
/// <param name="modelDC">所在列</param>
/// <param name="PageID">前一页页编号</param>
/// <param name="PageIndex">页号</param>
/// <returns></returns>
public static ContentPageEntity NewContentPage(DataColumnEntity modelDC, long PageID, int PageIndex)
{
long NextPageID = DataFileManage.GetEmptyPageID(modelDC.Table.DataFile);
//修改前一页
WriteNextPageID(new DataPageEntity { DataFile = modelDC.Table.DataFile, ID = PageID }, NextPageID);
//创建数据分页
byte[] array = new byte[Config.PAGE_SIZE];
array[0] = Convert.ToByte(EPageType.DataContent);
DataPageEntity modelDP = new DataPageEntity { DataFile = modelDC.Table.DataFile, ID = NextPageID, Content = array };
DataPageManage.Write(modelDP);
modelDP.Content = null;
//创建实体
ContentPageEntity modelCP = new ContentPageEntity { Column = modelDC, DataPage=modelDP, PageIndex = PageIndex, Contents = new List<DataContentEntity>() };
return modelCP;
}
/// <summary>
/// 读取内容页
/// </summary>
/// <param name="modelDP"></param>
/// <returns></returns>
public static ContentPageEntity ReadContentPage(DataPageEntity modelDP,ContentPageEntity modelCP)
{
DataPageManage.Read(modelDP);
modelCP.DataPage = modelDP;
modelCP.FromBytes(modelDP.Content);
modelDP.Content = null;
return modelCP;
}
/// <summary>
/// 根据行号获取某数据分页
/// </summary>
/// <param name="modelDC"></param>
/// <param name="index"></param>
/// <returns></returns>
public static ContentPageEntity GetPage(DataColumnEntity modelDC, int RowIndex)
{
long ContentPageID = modelDC.ContentPageID;
int PageIndex = 0;
ContentPageEntity modelCP = new ContentPageEntity();
if (RowIndex / modelDC.PageMaxCount == 0)//第一页
{
modelCP = ReadContentPage(new DataPageEntity { DataFile = modelDC.Table.DataFile, ID = ContentPageID },new ContentPageEntity { Column = modelDC, PageIndex = PageIndex });
}
else//不是第一页
{
//遍历寻找前一页编号
for (int i = 0; i <= RowIndex / modelDC.PageMaxCount - 2; i++)
{
ContentPageID = ReadNextPageID(new DataPageEntity { DataFile = modelDC.Table.DataFile, ID = ContentPageID });
PageIndex++;
}
long NextPageID = ReadNextPageID(new DataPageEntity { DataFile = modelDC.Table.DataFile, ID = ContentPageID });
if (NextPageID > 0)//有当前页
{
ContentPageID = NextPageID;
modelCP = ReadContentPage(new DataPageEntity { DataFile = modelDC.Table.DataFile, ID = ContentPageID }, new ContentPageEntity { Column = modelDC, PageIndex = PageIndex });
}
else//页不存在创建新页
{
modelCP = NewContentPage(modelDC, ContentPageID, PageIndex);
}
}
return modelCP;
}
