public class SqlExecutor
{
private static string connStr=null;
public static void SetConnStr(string connstr)
{
connStr=connstr;
}
public static void ExecuteNonQuery(string sqlstr)
{
string connstr=connStr;
if(connstr==null)throw new Exception("系统错误!");
OleDbConnection oleDbConnection1=new OleDbConnection(connstr);
oleDbConnection1.Open();
try
{
OleDbCommand myCommand=new OleDbCommand(sqlstr,oleDbConnection1);
myCommand.ExecuteNonQuery();
myCommand.Dispose();
}
finally
{
oleDbConnection1.Close();
oleDbConnection1.Dispose();
}
}
}
{
private static string connStr=null;
public static void SetConnStr(string connstr)
{
connStr=connstr;
}
public static void ExecuteNonQuery(string sqlstr)
{
string connstr=connStr;
if(connstr==null)throw new Exception("系统错误!");
OleDbConnection oleDbConnection1=new OleDbConnection(connstr);
oleDbConnection1.Open();
try
{
OleDbCommand myCommand=new OleDbCommand(sqlstr,oleDbConnection1);
myCommand.ExecuteNonQuery();
myCommand.Dispose();
}
finally
{
oleDbConnection1.Close();
oleDbConnection1.Dispose();
}
}
}
public static SqlExecutor createinstance(){
if(singleton_instance_ref == null){
singleton_instance_ref = new SqlExecutor();
}
return singleton_instance_ref;
}
private static SqlExecutor singleton_instance_ref = null;
----------------------------------
实现:
class _singleton_test{
public static void Main(){
SqlExecutor ref_singleton = SqlExecutor.createinstance();
SqlExecutor ref_singleton_ = SqlExecutor.createinstance();
}
}------------------------------------
这是设计模式里的单件模式(Singleton)