using 什么时候用
public AccountInfo SignIn(string userId, string password) {
SqlParameter[] signOnParms = GetSignOnParameters();
signOnParms[0].Value = userId;
signOnParms[1].Value = password;
using (SqlDataReader rdr = SQLHelper.ExecuteReader(SQLHelper.CONN_STRING_NON_DTC, CommandType.Text, SQL_SELECT_ACCOUNT, signOnParms)) {
...
}
}
请问这里为什么要用using,一直不太明白这里用using的意思,请明白的您告诉我,谢谢!