datareader分页

项目中有对未知数据源获取数据用于展示的需求，用dapper和datareader来分页，处理起来比较方便些。

public object View(string dbLinkId, int rows = 0, int page = 0)
        {
            Models.DBC.DataLink.DataLink info = Get(dbLinkId);
            Models.Integrate.DataBase dbsrc = new Integrate.DBSrcImpl().Get(info.DbsrcId) as Models.Integrate.DataBase;

            DynamicParameters p;
            string sql = getSql(dbLinkId, dbsrc, out p);

            int start = 0;
            if (page == 0)
            {
                page = 1;
            }
            if (rows == 0)
            {
                rows = 20;
            }
            start = (page - 1) * rows;
            int end = start + rows;

            int totalCount = 0;

            try
            {
                using (DbConnection conn = DapperFactory.CreateConnection(dbsrc))
                {
                    string countsql = string.Format("select count(0) from({0})t", sql);
                    int count = conn.ExecuteScalar<int>(countsql, p);

                    DataTable dt = new DataTable();
                    IDataReader reader = conn.ExecuteReader(sql, p);
                    for (int i = 0; i < reader.FieldCount; i++)
                    {
                        dt.Columns.Add(reader.GetName(i));
                    }

                    while (reader.Read())
                    {
                        totalCount++;
                        if (totalCount > end)
                            break;
                        if (totalCount >= start && totalCount <= end)
                        {
                            DataRow r = dt.NewRow();
                            for (int i = 0; i < reader.FieldCount; i++)
                            {
                                r[i] = reader[i];
                            }
                            dt.Rows.Add(r);
                        }
                    }

                    return Common.DataGrid(dt, count);//转成easyui datagrid数据源格式
                }
            }
            catch (Exception e)
            {
                throw new Exception(string.Format("查询源数据库出错<br>原因：{0}<br>sql语句：{1}", e.Message, sql));
            }
        }      

function getdata(id,r,p) {
        var rows = 50;
        var page = 1;
        if (r) rows = r;
        if (p) page = p;

        $.post('/dblink/ListView', { id: id, rows: rows, page: page }, function (data) {
            accecpResult(data, function () {
                var ds = data.data.rows;
                var columns = [[]];
                if (ds.length > 0) {
                    for (var key in ds[0]) {
                        columns[0].push({ field: key, title: key });
                    }
                }

                tab_view.datagrid({
                    data: data.data,
                    rownumbers: true,
                    singleSelect: true,
                    striped: true,
                    fit: true,
                    border: false,
                    pagination: true,
                    pageSize: 50,
                    columns: columns
                });
                var p = tab_view.datagrid('getPager');
                (p).pagination({
                    pageNumber: page,
                    beforePageText: '第',
                    afterPageText: '页    共 {pages} 页',
                    displayMsg: '共{total}条数据',
                    onSelectPage: function (pageNumber, pageSize)