NextResult()问题
string   strcnn= "Provider=Microsoft.Jet.OLEDB.4.0;Data   Source=D:\\vsio\\mydata.mdb "; 
 	string   sql= "select   xuehao,score   from   score;select   num,xuehao,name   from   student "; 
                            OleDbConnection   connection=new   OleDbConnection(strcnn); 
 	try 
 	{ 
 	   connection.Open(); 
 	   Console.WriteLine( "The   Access   data   is   {0} ",connection.State); 
 	   OleDbCommand   command=connection.CreateCommand(); 
 	   command.CommandText=sql; 
 	   OleDbDataReader   reader=command.ExecuteReader(); 
 	   while(reader.Read()) 
 	   { 
 	         Console.WriteLine( "\t{0}\t{1} ",reader[ "xuehao "],reader[ "score "]); 
 	   } 
 	Console.WriteLine( "The   data   in   \ "student.mdb\ "   is   read   completely ");   
 	reader.NextResult(); 
 	int   num=reader.FieldCount; 
 	for(int   i=0;i <num;i++) 
 	{ 
 	      Console.WriteLine( "\t{0}\t{1} ",reader[ "xuehao "],reader[ "name "]); 
 	} 
 	      Console.WriteLine( "The   data   in   \ "score.mdb\ "   is   read   completely "); 
 	reader.Close(); 
 	}                     
 	写上string   sql= "select   xuehao,score   from   score;select   num,xuehao,name   from   student ";这句之后,就一个数据库的内容也显示不了了,但单写任何一个都没问题
------解决方案--------------------reader.NextResult(); 
 之后你还是要用 
 while(reader.Read()) 
 { 
 } 
 来读取数据   
 即 
 reader.NextResult(); 
 	int num=reader.FieldCount; 
 	for(int i=0;i <num;i++) 
 	{ 
            while(reader.Read()) 
           { 
 	     Console.WriteLine( "\t{0}\t{1} ",reader[ "xuehao "],reader[ "name "]); 
           } 
 	} 
------解决方案--------------------up
------解决方案--------------------看MSDN