共享数据访问类！

Question

namespace DataAccess
{ public class SqlHelper
{
public SqlHelper()
{ } /// <summary>
/// SqlServer连接字符串
/// </summary>
private static string connectionstring="Server=192.168.1.42;DataBase=wuhan;Uid=sa;pwd=123456"; private static SqlConnection Sqlconnection(string connectionstring)
{
    SqlConnection sqlconnection=new SqlConnection(connectionstring);
if(sqlconnection.State!=ConnectionState.Open)
sqlconnection.Open();
return sqlconnection;
}
/// <summary>
/// SqlCommand对象
/// </summary>
/// <param name="commandText">SQL语句</param>
/// <param name="sqlconnection">SqlConnection对象</param>
/// <returns></returns>
private static SqlCommand Sqlcommand(string commandText,SqlConnection sqlconnection)
{
    SqlCommand CommandText=new SqlCommand(commandText,sqlconnection);
    return CommandText;
} /// <summary>
/// SqlDataAdapter对象
/// </summary>
/// <param name="commandText">SQL语句</param>
/// <param name="sqlconnection">SqlConnection对象</param>
/// <returns></returns>
private static SqlDataAdapter SqlDataadqpter(string commandText,SqlConnection sqlconnection)
{
SqlCommand CommandText=Sqlcommand(commandText,sqlconnection);
    SqlDataAdapter Ads=new SqlDataAdapter(CommandText);
return Ads;
}

/// <summary>
/// SqlDataReader对象
/// </summary>
/// <param name="commandText">SQL语句</param>
/// <returns></returns>
public static SqlDataReader DataReader(string commandText)
{
string connection=connectionstring;
SqlDataReader dr=Sqlcommand(commandText,Sqlconnection(connection)).ExecuteReader();
Sqlconnection(connection).Close();
return dr;
}
/// <summary>
/// DataSet对象
/// </summary>
/// <param name="commandText">SQL语句</param>
/// <returns></returns>
public static DataSet ExecuteDataSet(string commandText)
{
   DataSet dbSet=new DataSet();
   SqlDataadqpter(commandText,Sqlconnection(connectionstring)).Fill(dbSet);
   return dbSet;
}
/// <summary>
/// 执行编辑、删除,写入,命令
/// </summary>
/// <param name="commandText">SQL语句</param>
        /// <returns></returns>
public static int ExecuteNonquery(string commandText)
{
   Sqlcommand(commandText,Sqlconnection(connectionstring)).ExecuteNonQuery();
   Sqlconnection(connectionstring).Close();
   return ExecuteNonquery(commandText);
}
/// <summary>
/// 执行编辑、删除,写入,命令
/// </summary>
/// <param name="CommandText">事务过程名称</param>
/// <param name="Parameters">事务过程数组</param>
/// <param name="commandText">事务过程标识</param>
/// <returns></returns>
public static int ExecuteNonquery(string CommandText,SqlParameter[] Parameters,CommandType commandText)
{
SqlCommand cmd=Sqlcommand(CommandText,Sqlconnection(connectionstring));
    cmd.CommandType=commandText;
foreach(SqlParameter commandParameter in Parameters)
cmd.Parameters.Add(commandParameter.ParameterName,commandParameter.Value);
return cmd.ExecuteNonQuery();
} }
}