Access数据库操作类（AccessHelper）

using System; using System.Data; using System.Data.OleDb; /// <summary> ///Access数据库操作类 ///创建时间：2010年4月16日17时9分 /// </summary> public class AccessHelper { private OleDbConnection conn = null; private OleDbCommand cmd = null; private OleDbDataReader sdr = null; public AccessHelper() { // string connStr = WebConfigurationManager.ConnectionStrings["connStr"].ToString(); string connStr = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=|DataDirectory|db.mdb"; conn = new OleDbConnection(connStr); } /// <summary>创建Command对象 /// /// </summary> /// SQL语句 public void CreateCommand(string sql) { conn.Open(); cmd = new OleDbCommand(sql, conn); } /// <summary>添加参数 /// /// </summary> /// 参数名称 /// 值 public void AddParameter(string paramName, object value) { cmd.Parameters.Add(new OleDbParameter(paramName, value)); } /// <summary>执行不带参数的增删改SQL语句 /// /// </summary> /// 增删改SQL语句 /// 命令类型 /// <returns></returns> public bool ExecuteNonQuery() { int res; try { res = cmd.ExecuteNonQuery(); if (res > 0) { return true; } } catch (Exception ex) { throw ex; } finally { if (conn.State == ConnectionState.Open) { conn.Close(); } } return false; } /// <summary>执行查询SQL语句 /// /// </summary> /// 查询SQL语句 /// <returns></returns> public DataTable ExecuteQuery() { DataTable dt = new DataTable(); using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)) { dt.Load(sdr); } return dt; } /// <summary>分页 /// /// </summary> /// 表名 /// 字段名 /// 排序字段名 /// 排序方式：asc或者desc /// 条件，不用加where /// 页大小 /// 页索引 /// <returns></returns> public DataTable FengYe(string tblName, string fldName, string OrderfldName, string OrderType, string strWhere, int PageSize, int PageIndex) { DataTable dt = new DataTable(); string strSQL = ""; // 主语句 string strTmp = ""; // 临时变量 string strOrder = ""; // 排序类型 if (OrderType == "desc") { // 降序 strTmp = "(select max"; strOrder = " order by " + OrderfldName + " asc"; } #region 第一页 if (PageIndex == 1) { strTmp = string.IsNullOrEmpty(strWhere) ? "" : " where " + strWhere; strSQL = "select top " + PageSize + " " + fldName + " from " + tblName + strTmp + " " + strOrder; CreateCommand(strSQL); dt = ExecuteQuery(); return dt; } #endregion #region 不是第一页 if (string.IsNullOrEmpty(strWhere)) { // 条件为空 strSQL = string.Format("select top {0} {1} from {2} where {3}{4}({5}) from (select top {6} {7} from {8} {9}) as tblTmp) {10}", PageSize, fldName, tblName, OrderfldName, strTmp, OrderfldName, (PageIndex - 1) * PageSize, OrderfldName, tblName, strOrder, strOrder); CreateCommand(strSQL); dt = ExecuteQuery(); } else { // 条件不为空 strSQL =string.Format( "select top {0} {1} from {2} where {3}{4}({5}) from (select top {6} {7} from {8} where {9} {10}) as tblTmp) and {11} {12}",PageSize,fldName,tblName,OrderfldName,strTmp,OrderfldName,(PageIndex-1)*PageSize,OrderfldName,tblName,strWhere,strOrder,strWhere,strOrder); CreateCommand(strSQL); dt = ExecuteQuery(); } #endregion return dt; } /// <summary>返回查询SQL语句查询出的结果的第一行第一列的值 /// /// </summary> /// <returns></returns> public string ExecuteScalar() { string res = ""; try { object obj = cmd.ExecuteScalar(); if (obj != null) { res = obj.ToString(); } } catch (Exception ex) { throw ex; } finally { if (conn.State == ConnectionState.Open) { conn.Close(); } } return res; } }