//查询public static DataSet select(string tableName,string whereStr){    string sql = "select * from "+tableName+whereStr;    try    {        return DbHelp.ExecSql(sql);    }    catch (Exception e1)    {        return null;    }    }//删除单条public static int delete (string tableName,string whereStr){    string sql = "delete from "+tableName+whereStr;    try    {        return DbHelp.ExecSql(sql);    }    catch (Exception e1)    {        return 0;    }    }//删除多条public static string deltes(DataTable dt){    int i = 0;    if (dt != null && dt.Rows.Count > 0)    {        foreach (DataRow row in dt.Rows) //遍历行        {            string tableName = dt.Name;            string pk = dt.Columns[0].ColumnName.ToString(); //获取第一列名（主键列）            string pkValue = http://www.mamicode.com/row[0].ToString(); //获取第一行的（主键值）            string sql="delete from "+tableNmae+" where "+pk+" = ‘"+pkValue+"‘";            try            {                i = i + DbHelp.ExecSql(sql);            }            catch (Exception e1)            {                return e1.Massage.ToString()+sql;            }                    }        return "删除"+i.ToString()+"条信息";    }    else    {        return "删除0行";    }}//遍历dataTable新增public static string add(DataTable dt){    int k=0;    if (dt != null && dt.Rows.Count > 0)    {        foreach (DataRow row in dt.Rows) //遍历行        {            string tableName = dt.Name;            string pk = dt.Columns[0].ColumnName.ToString(); //获取第一列名（主键列）            string pkValue = http://www.mamicode.com/row[0].ToString(); //获取第一行的（主键值）            string sql="insert into "+tableNmae+" values(";            string sql1 = pk;            string sql2 = "‘"+pkValue+"‘";            for (int i = 1; i < dt.Columns.Count; i++) //从1开始，因为第一列为主键值            {                sql1 = sql1 + ","+dt.Columns[i].ColumnName.ToString();  //拼列明                sql2 = sql2 + ",‘"+row[i].ToString()+"‘";  //拼值                //sql1 = sql1 + dt.Columns[i].ColumnName + "= ‘" + row[i].ToString() + "‘,";//列名+列值            }            sql = sql + sql1 +") values("+sql2 +")";            try            {                k = k+DbHelp.ExecSql(sql);            }            catch (Exception e1)            {                return e1.Massage.ToString()+sql;            }                    }        return "新增"+k.ToString()+"条信息";    }    return "新增0条信息";}//遍历dataTable修改public static string add(DataTable dt){    int k = 0;    if (dt != null && dt.Rows.Count > 0)    {        foreach (DataRow row in dt.Rows) //遍历行        {            string tableName = dt.Name;            string pk = dt.Columns[0].ColumnName.ToString(); //获取第一列名（主键列）            string pkValue = http://www.mamicode.com/row[0].ToString(); //获取第一行的（主键值）            string sql="update "+tableNmae+" set ";            for (int i = 1; i < dt.Columns.Count; i++) //从1开始，因为第一列为主键值            {                sql1 = sql1 + dt.Columns[i].ColumnName + "= ‘" + row[i].ToString() + "‘,";//列名+列值            }            sql = sql.Substring(0,sql.Length -1) + " where "+pk+" = ‘"+pkValue+"‘";            try            {                k = k+DbHelp.ExecSql(sql);            }            catch (Exception e1)            {                return e1.Massage.ToString()+sql;            }                    }        return "修改"+k.ToString()+"条信息";    }    return "修改0条信息";}