SqlHelper数据库访问类
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
namespace CommDAL
{
public class SqlHelper
{
private string sqlConnString; // 数据库连接字符串
private SqlConnection sqlConn = new SqlConnection(); // SQL数据库连接对象
private ConnectionState sqlConnPreState = ConnectionState.Closed; //原来数据库的连接状态
/// <summary>
/// 数据库连接字符串属性。
/// </summary>
public string SqlConnectionString
{
get
{
return sqlConnString;
}
set
{
sqlConnString = value;
sqlConn.ConnectionString = sqlConnString;
}
}
public SqlHelper()
{
}
/// <summary>
/// 构造函数。
/// </summary>
/// <param name="strSqlCon">数据库连接字符串。</param>
public SqlHelper(string strSqlCon)
{
sqlConnString = strSqlCon;
sqlConn.ConnectionString = sqlConnString;
}
/// <summary>
/// 析构函数。
/// </summary>
~SqlHelper()
{
try
{
Close();
sqlConn.Dispose();
}
catch (Exception ex)
{
//throw ex;
Console.Write(ex.Message);
}
}
/// <summary>
/// 打开数据库连接。
/// </summary>
public void Open()
{
try
{
if (sqlConn.State == ConnectionState.Closed)
{
sqlConn.Open();
sqlConnPreState = ConnectionState.Open;
}
}
catch (Exception ex)
{
throw ex;
}
}
/// <summary>
/// 关闭数据库连接。
/// </summary>
public void Close()
{
try
{
if (sqlConn.State != ConnectionState.Closed)
{
sqlConn.Close();
sqlConnPreState = ConnectionState.Closed;
}
}
catch (Exception ex)
{
throw ex;
}
}
/// <summary>
/// 获取查询的数据表。
/// </summary>
/// <param name="strSQL">要查询的SQL语句。</param>
/// <param name="parametes">传入的参数，无参数时使用NULL。</param>
/// <returns></returns>
public DataTable GetDataTable(string strSQL, params SqlParameter[] parametes)
{
DataSet ds = new DataSet();
DataTable dt = new DataTable();
try
{
//sqlConn.Open();
if (sqlConn.State == ConnectionState.Closed && sqlConn.State == ConnectionState.Closed) //若原来的状态为关闭且当前连接未打开
{
sqlConn.Open();
}
SqlCommand sqlCmd = sqlConn.CreateCommand();
sqlCmd.CommandText = strSQL;
if (parametes != null)
{
sqlCmd.Parameters.Clear();
sqlCmd.Parameters.AddRange(parametes);
}
SqlDataAdapter da = new SqlDataAdapter(sqlCmd);
da.Fill(ds);
dt = ds.Tables[0];
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (sqlConnPreState == ConnectionState.Closed && sqlConn.State != ConnectionState.Closed) //若原来的状态为关闭且者当前连接未关闭则关闭
{
sqlConn.Close();
}
}
return dt;
}
/// <summary>
/// 获取查询的数据集。
/// </summary>
/// <param name="strSQL">要查询的SQL语句。</param>
/// <param name="parametes">传入的参数，无参数时使用NULL。</param>
/// <returns></returns>
public DataSet GetDataSet(string strSQL, params SqlParameter[] parametes)
{
DataSet ds = new DataSet();
try
{
//sqlConn.Open();
if (sqlConn.State == ConnectionState.Closed && sqlConn.State == ConnectionState.Closed) //若原来的状态为关闭且当前连接未打开
{
sqlConn.Open();
}
SqlCommand sqlCmd = sqlConn.CreateCommand();
sqlCmd.CommandText = strSQL;
if (parametes != null)
{
sqlCmd.Parameters.Clear();
sqlCmd.Parameters.AddRange(parametes);
}
SqlDataAdapter da = new SqlDataAdapter(sqlCmd);
da.Fill(ds);
sqlConn.Close();
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (sqlConnPreState == ConnectionState.Closed && sqlConn.State != ConnectionState.Closed) //若原来的状态为关闭且者当前连接未关闭则关闭
{
sqlConn.Close();
}
}
return ds;
}
/// <summary>
/// 返回SqlDataReader对象。该函数需要在外部打开和关闭连接操作。
/// </summary>
/// <param name="strSQL">传入的SQL语句。</param>
/// <param name="parametes">传入的参数，无参数时使用NULL。</param>
/// <returns></returns>
public SqlDataReader ExecuteReader(string strSQL, params SqlParameter[] parametes)
{
SqlDataReader reader;
try
{
if (sqlConn.State == ConnectionState.Closed && sqlConn.State == ConnectionState.Closed) //若原来的状态为关闭且当前连接未打开
{
sqlConn.Open();
}
//SqlCommand sqlCmd = sqlConn.CreateCommand();
SqlCommand sqlCmd = sqlConn.CreateCommand();
sqlCmd.CommandText = strSQL;
if (parametes != null)
{
sqlCmd.Parameters.Clear();
sqlCmd.Parameters.AddRange(parametes);
}
//reader = sqlCmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
reader = sqlCmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
}
catch (Exception ex)
{
throw ex;
}
return reader;
}
/// <summary>
/// 返回执行T-SQL语句受影响的行数。
/// </summary>
/// <param name="strSQL">执行的SQL语句。</param>
/// <param name="parametes">传入的参数，无参数时使用NULL。</param>
/// <returns></returns>
public int ExecuteNonQuery(string strSQL, params SqlParameter[] parametes)
{
int sqlInt = -1;
try
{
if (sqlConn.State == ConnectionState.Closed && sqlConn.State == ConnectionState.Closed) //若原来的状态为关闭且当前连接未打开
{
sqlConn.Open();
}
SqlCommand sqlCmd = sqlConn.CreateCommand();
sqlCmd.CommandText = strSQL;
if (parametes != null)
{
sqlCmd.Parameters.Clear();
sqlCmd.Parameters.AddRange(parametes);
}
sqlInt = sqlCmd.ExecuteNonQuery();
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (sqlConnPreState == ConnectionState.Closed && sqlConn.State != ConnectionState.Closed) //若原来的状态为关闭且者当前连接未关闭则关闭
{
sqlConn.Close();
}
}
return sqlInt;
}
/// <summary>
/// 执行查询并返回第一行第一列的值。
/// </summary>
/// <param name="strSQL">执行的SQL语句。</param>
/// <param name="parametes">传入的参数，无参数时使用NULL。</param>
/// <returns></returns>
public object ExecuteScalar(string strSQL, params SqlParameter[] parametes)
{
object obj;
try
{
if (sqlConn.State == ConnectionState.Closed && sqlConn.State == ConnectionState.Closed) //若原来的状态为关闭且当前连接未打开
{
sqlConn.Open();
}
SqlCommand sqlCmd = sqlConn.CreateCommand();
sqlCmd.CommandText = strSQL;
if (parametes != null)
{
sqlCmd.Parameters.Clear();
sqlCmd.Parameters.AddRange(parametes);
}
obj = sqlCmd.ExecuteScalar();
}
catch (Exception ex)
{
throw ex;
}
//finally
//{
// if (sqlConnPreState == ConnectionState.Closed && sqlConn.State != ConnectionState.Closed) //若原来的状态为关闭且者当前连接未关闭则关闭
// {
// sqlConn.Close();
// }
//}
return obj;
}
}
}