private static void FilterPager(MDataRowCollection rows, int pageIndex, int pageSize)
{
if (pageIndex > -1 && pageSize > 0) //分页处理返回
{
pageIndex = pageIndex == 0 ? 1 : pageIndex;
int start = (pageIndex - 1) * pageSize; //从第几条开始查(索引)
int end = start + pageSize; //查到第N条结束(索引)。
int rowCount = rows.Count;
if (rowCount > end) //总数>N
{
//rows.re
rows.RemoveRange(end, rowCount - end); //移除尾数
}
if (start > 0) //总数>起即
{
if (rowCount > start)
{
rows.RemoveRange(0, start);//移除起始数
}
else// if (rowCount < start) //查询的超出总数
{
rows.Clear();//直接清空返回
}
}
}
}
public static MDataTable Select(MDataTable table, int pageIndex, int pageSize, object whereObj, params object[] selectColumns)
{
if (table == null)
{
return(null);
}
MDataTable sTable = table.GetSchema(true);
sTable.RecordsAffected = table.Rows.Count;
if (table.Rows.Count == 0) // 正常情况下，看是否需要处理列移除
{
FilterColumns(ref sTable, selectColumns); //列查询过滤
return(sTable);
}
MDataRowCollection findRows = FindAll(table, whereObj);
if (findRows != null)
{
sTable.RecordsAffected = findRows.Count; //设置记录总数
FilterPager(findRows, pageIndex, pageSize); //进行分页筛选，再克隆最后的数据。
for (int i = 0; i < findRows.Count; i++)
{
if (i < findRows.Count)//内存表时（表有可能在其它线程被清空）
{
MDataRow row = findRows[i];
if (row == null)
{
break;
}
sTable.NewRow(true).LoadFrom(row);
}
}
findRows = null;
}
if (selectColumns != null && selectColumns.Length > 0)
{
FilterColumns(ref sTable, selectColumns);//列查询过滤，由于查询的条件可能包含被移除列，所以只能在最后才过滤
}
//进行条件查询
return(sTable);
}
public static MDataRowCollection FindAll(MDataTable table, object whereObj)
{
if (table != null && table.Rows.Count > 0)
{
MDataRowCollection findRows = new MDataRowCollection();
string where = Convert.ToString(whereObj).Trim();
if (where == "" || where == "1=1")
{
findRows.AddRange(table.Rows);
return(findRows);
}
string whereStr = SqlFormat.GetIFieldSql(whereObj);
string orderby;
SplitWhereOrderby(ref whereStr, out orderby);
List <TFilter> group2 = null;
List <TFilter> filters = GetTFilter(whereStr, table.Columns, out group2);
IList <MDataRow> rows = table.Rows;
if (filters.Count > 0)
{
rows = table.Rows.FindAll(delegate(MDataRow row)
{
return(CompareMore(row, filters) && (group2.Count == 0 || CompareMore(row, group2)));
}
);
}
findRows.AddRange(rows); //添加找到的行。
filters = null;
if (!string.IsNullOrEmpty(orderby) && rows.Count > 1) //进行数组排序
{
findRows.Sort(orderby);
//MDataRowCollection sortRows = new MDataRowCollection();
//sortRows.AddRange(rows);
//sortRows.Sort(orderby);
//return sortRows;
}
return(findRows);
}
return(null);
}
public static MDataRow FindRow(MDataTable table, object whereObj)
{
if (table.Rows.Count > 0)
{
if (Convert.ToString(whereObj).Trim() == "")
{
return(table.Rows[0]);
}
string whereStr = SqlFormat.GetIFieldSql(whereObj);
string orderby;
SplitWhereOrderby(ref whereStr, out orderby);
MDataRowCollection sortRows = null;
if (!string.IsNullOrEmpty(orderby) && table.Rows.Count > 1)//进行数组排序
{
sortRows = new MDataRowCollection();
sortRows.AddRange(table.Rows);
sortRows.Sort(orderby);
}
List <TFilter> group2 = null;
List <TFilter> filters = GetTFilter(whereStr, table.Columns, out group2);
if (filters.Count > 0)
{
if (sortRows == null)
{
sortRows = table.Rows;
}
for (int i = 0; i < sortRows.Count; i++)
{
if (CompareMore(sortRows[i], filters) && (group2.Count == 0 || CompareMore(sortRows[i], group2)))
{
return(sortRows[i]);
}
}
}
}
return(null);
}