ASP.NET中Dataset的table数据合并、数据截取、数据排序

1、两个相同字段表的合并：

public static DataSet CombineTables(DataSet _ds, DataTable _dt1, DataTable _dt2)
        {
            DataSet ds = _ds.Clone();
            //ds.Tables[0].Clone();
            ds.Tables[0].Rows.Clear();
            int i = 0;
            for ( i = 0; i < _dt1.Rows.Count; i++)
            {
                ds.Tables[0].ImportRow(_dt1.Rows[i]);
            }
            for (int j = 0; j < _dt2.Rows.Count; j++)
            {
                ds.Tables[0].ImportRow(_dt2.Rows[j]);
            }
            return ds;
        }

2、对表的数据截取：

public static DataSet CopyScopeRows(DataSet source, int startRowNum, int endRowNum) {
            DataSet des = source.Clone();
            des.Tables[0].Rows.Clear();
            for (int i = startRowNum; i < source.Tables[0].Rows.Count && i <= endRowNum; i++) {
                des.Tables[0].ImportRow(source.Tables[0].Rows[i]);
            }
            return des;
        }

3、数据行的筛选：

public static DataSet CopyScopeRows(DataSet source, string filter) {
            DataSet des = source.Clone();
            DataSet _ds = null;
            des.Tables[0].Rows.Clear();
            try
                {
            DataRow[] rows = source.Tables[0].Select(filter);
            foreach (DataRow row in rows) {
                des.Tables[0].ImportRow(row);
            }}
            catch (Exception ex) { return _ds; }
            finally
                {}
            return des;
        }

4、数据行的筛选，并可以排序：

public static DataSet CopyScopeRows(DataSet source, string filter, string order) {
            DataSet des = source.Clone();
            des.Tables[0].Rows.Clear();
            DataRow[] rows = source.Tables[0].Select(filter, order);
            foreach (DataRow row in rows) 
            {
                des.Tables[0].ImportRow(row);
            }
            return des;
        }

5、数据行的筛选，并可截取数据行：

public static DataSet CopyScopeRows(DataSet source, string filter, int startRowNum, int endRowNum) {
            DataSet des = source.Clone();
            des.Tables[0].Rows.Clear();
            DataRow[] rows = source.Tables[0].Select(filter);
            for (int i = startRowNum; i < rows.Length && i <= endRowNum; i++)
            {
                des.Tables[0].ImportRow(rows[i]);
            }
            return des;
        }

6、数据行的筛选、排序，并可截取数据行：

public static DataSet CopyScopeRows(DataSet source, string filter, string order, int startRowNum, int endRowNum) {
            DataSet des = source.Clone();
            des.Tables[0].Rows.Clear();
            DataRow[] rows = source.Tables[0].Select(filter, order);
            for (int i = startRowNum; i < rows.Length && i <= endRowNum; i++) {
                des.Tables[0].ImportRow(rows[i]);
            }
            return des;
        }

public static object GetValueByKey(DataTable table, string keyName, object keyValue, string returnName) {
            object obj = null;
            table.PrimaryKey = new DataColumn[] { table.Columns[keyName] };
            DataRow row = table.Rows.Find(keyValue);
            if (row != null) { obj = row[returnName]; }
            return obj;
        }

public static object GetValueByKeys(DataTable table,  object[] keyValue, string returnName)
        {
            object obj = null;
           
            DataColumn[] keys = new DataColumn[2];
            keys[1] = table.Columns[0];
            keys[0] = table.Columns[2];
            table.PrimaryKey = keys;
           
            DataRow row = table.Rows.Find(keyValue);
            if (row != null) { obj = row[returnName]; }
            return obj;
        }