急啊！急！请教各位大侠一个简单的问题！（用VS.NET(C#)的请进！）

Question

ExecuteNonQuery()
ExecuteScalar()

Answer 1

string strConnect="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=XXXXX.mdb;Persist Security Info=False;";
conn=new OleDbConnection(strConnect);string strSQL="SELECT * FROM YYYYY";

DataSet ds = new DataSet() ;// 创建一个 DataSet

conn.Open() ;

OleDbDataAdapter command = new OleDbDataAdapter(strSQL,conn);// 用 OleDbDataAdapter 得到一个数据集command.Fill(ds,"LangSort");//把Dataset绑定到数据表
DataTable dt=ds.Tables["LangSort"];
LangSortRows=dt.Rows;
--------------------------------------------------------------------------------
string query="UPDATE Code SET Title='";
query+=drCode[1].ToString()+"',LangSort='";
query+=drCode[2].ToString()+"',InputE='";
query+=drCode[3].ToString()+"',OutputE='";
query+=drCode[4].ToString()+"',Code='";
query+=drCode[5].ToString()+"',InputerName='";
query+=drCode[6].ToString()+"',InputTime='";
query+=drCode[7].ToString()+"',Origin='";
query+=drCode[8].ToString()+"',NoteE='";
query+=drCode[9].ToString()+"'";
query+=" WHERE ID="+nif.CodeID;

OleDbCommand command =new OleDbCommand(query,conn);

int i=command.ExecuteNonQuery();
if (i==-1)
{
   //error
   MessageBox.Show(this,"XXXXXX!","XXXXX",MessageBoxButtons.OK,MessageBoxIcon.Error);
}
else
{
   //更新数据成功后的代码
}

Answer 2

1，
stringconStr="server=(local);database=XX;uid=sa;pwd=";           SqlConnection con=new SqlConnection(conStr);           string sql="select count(*) from users where name='"+name+"' and pwd='"+pwd+"';";           SqlCommand cmd=new SqlCommand(sql,con);           con.Open();           int n=(int)cmd.ExecuteScalar();           con.Close();
2，
stringconStr="server=(local);database=XX;uid=sa;pwd=";           SqlConnection con=new SqlConnection(conStr);           string sql="select adrress from users where name='"+name+"' and pwd='"+pwd+"';";           SqlCommand cmd=new SqlCommand(sql,con);           con.Open();           string a=cmd.ExecuteScalar().ToString();           con.Close();

Answer 3

http://blog.csdn.net/foolnet/archive/2005/01/20/260705.aspx

Answer 4

sql="select top 8 id,新闻标题 ,发布时间 from 新闻 order by id desc";
dr=myado.ExecuteRead(sql);
if(dr.read())
{
  string a=dr["新闻标题"].string();
}