DBHelperAccess连接数据库

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Data;
using System.Data.OleDb;

namespace FlyingTanker
{
public class DBHelperAccess
{
public static string strAccess = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + System.IO.Directory.GetCurrentDirectory() + "\\TankerAircraft.accdb;";
private static OleDbConnection conn;
private static OleDbDataAdapter oda = new OleDbDataAdapter();
private OleDbCommand cmd;
/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataSet</returns>
public static DataSet Query(string SQLString)
{
DataSet ds = new DataSet();
conn = new OleDbConnection(strAccess);
try
{
conn.Open();
oda = new OleDbDataAdapter(SQLString, conn);
oda.Fill(ds, "ds");
}
catch
{

}
finally
{
conn.Close();
}
return ds;
}
/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="SQLString">查询语句</param>
/// <returns>DataSet</returns>
public static DataSet GetList(string SQLString)
{
return Query(SQLString);
}
/// <summary>
/// 执行查询语句，返回DataSet
/// </summary>
/// <param name="tabcolumn">列名</param>
/// <param name="tabname">表名</param>
/// <param name="SQLWhere">查询条件</param>
/// <returns></returns>
public static DataSet GetList(string tabcolumn, string tabname, string SQLWhere)
{
if (string.IsNullOrEmpty(SQLWhere))
{
SQLWhere = "1=1";
}
string str = "select " + tabcolumn + " from " + tabname + " where " + SQLWhere;
return Query(str);
}
/// <summary>
/// 执行SQL语句，返回影响的记录数
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <returns>影响的记录数</returns>
public static int ExecuteSql(string SQLString)
{
conn = new OleDbConnection(strAccess);

using (OleDbCommand cmd = new OleDbCommand(SQLString, conn))
{
try
{
conn.Open();
int rows = cmd.ExecuteNonQuery();
return rows;
}
catch (System.Data.SqlClient.SqlException e)
{
return -1;
}
finally
{
cmd.Dispose();
conn.Close();
}
}
}

/// <summary>
/// 执行一条计算查询结果语句，返回查询结果（object）。
/// </summary>
/// <param name="SQLString">计算查询结果语句</param>
/// <returns>查询结果（object）</returns>
public static object GetSingle(string SQLString)
{
conn = new OleDbConnection(strAccess);
using (OleDbCommand cmd = new OleDbCommand(SQLString, conn))
{
try
{
conn.Open();
object obj = cmd.ExecuteScalar();
if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
{
return null;
}
else
{
return obj;
}
}
catch (System.Data.SqlClient.SqlException e)
{
return null;
}
finally
{
conn.Close();
}
}
}

/// <summary>
/// 查看文件是否存在
/// </summary>
/// <returns></returns>
public static string GetFile()
{
string str = "";
var file = new FileInfo(strAccess);
if (!file.Exists)
{
str = "获取失败！";
}
return str;
}
/// <summary>
/// 记录测试记事本
/// </summary>
/// <param name="text">信息</param>
public static void WriteTextLog(string text)
{
try
{
string dirpath = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase + "LOG//" + DateTime.Now.ToString("yyyyMMdd") + "log.txt";
if (!File.Exists(dirpath))
{
FileStream fs1 = new FileStream(dirpath, FileMode.Create, FileAccess.Write);//创建写入文件
fs1.Close();
}
StreamWriter sw = new StreamWriter(dirpath, true);
sw.WriteLine(DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss") + ": " + text);
sw.Close();
}
catch
{

}
}
}
}