/// <summary>
/// 异步执行分页查询
/// 注意，SQL语句中一定要包含ORDER BY子句
/// </summary>
/// <param name="command">DbCommand</param>
/// <param name="preparePagingCommand">分页语句后续处理</param>
/// <param name="pageIndex">第几页</param>
/// <param name="pageSize">每页记录数</param>
/// <returns>PagingResult</returns>
public virtual async Task <PagingResult <DbDataReader> > ExecuteReaderPagingAsync(
DbCommand command,
Action <DbCommand, DatabaseAccess> preparePagingCommand,
int pageIndex,
int pageSize)
{
bool lastOpenedConnection = _openedConnection;
bool isOpen = false;
CommandBehavior behavior = CommandBehavior.Default;
try
{
await EnsureConnectionAsync();
isOpen = lastOpenedConnection != _openedConnection;
if (isOpen)
{
behavior = CommandBehavior.CloseConnection;
}
var rowCountTask = ReaderRowCountAsync(command, pageIndex, pageSize);
var pagingReaderTask = ExecutePagingDataReader(command, preparePagingCommand, pageIndex, pageSize, behavior);
int rowCount = await rowCountTask;
DbDataReader reader = await pagingReaderTask;
ReleaseConnection(false);
PagingResult <DbDataReader> result = new PagingResult <DbDataReader>
{
Result = reader,
RowCount = rowCount,
PageCount = PageCount(rowCount, pageSize)
};
return(result);
}
catch
{
if (isOpen)
{
ReleaseConnection();
}
else
{
ReleaseConnection(false);
}
throw;
}
}
/// <summary>
/// 执行分页查询
/// 注意，SQL语句中一定要包含ORDER BY子句
/// </summary>
/// <typeparam name="TResult">返回数据集的类型，该类型必须有空构造</typeparam>
/// <param name="command">DbCommand</param>
/// <param name="preparePagingCommand">分页语句后续处理</param>
/// <param name="readDataHandler">DbDataReader和数据集映射的委托</param>
/// <param name="pageIndex">第几页</param>
/// <param name="pageSize">每页记录数</param>
/// <returns>PagingResult数据集</returns>
public virtual async Task <PagingResult <TResult> > ExecuteReaderPagingAsync <TResult>(
DbCommand command,
Action <DbCommand, DatabaseAccess> preparePagingCommand,
Action <TResult, DbDataReader> readDataHandler,
int pageIndex,
int pageSize)
where TResult : new()
{
try
{
await EnsureConnectionAsync();
var rowCountTask = ReaderRowCountAsync(command, pageIndex, pageSize);
var pagingReaderTask = ExecutePagingDataReader(command, preparePagingCommand, pageIndex, pageSize, CommandBehavior.Default);
int rowCount = await rowCountTask;
DbDataReader reader = await pagingReaderTask;
TResult resultData = LoadResult <TResult>(reader, readDataHandler);
PagingResult <TResult> result = new PagingResult <TResult>
{
Result = resultData,
RowCount = rowCount,
PageCount = PageCount(rowCount, pageSize)
};
return(result);
}
catch
{
throw;
}
finally
{
ReleaseConnection();
}
}
