＆＃39;行/列没有数据。＆＃39; Oledb例外

Question

connection.Open();
OleDbCommand command = new OleDbCommand("SELECT [Names] FROM Test", 
connection);

OleDbDataReader reader = command.ExecuteReader();
string result = reader.GetValue(0).ToString();
        MessageBox.Show(result);
        connection.Close();

有人可以帮忙吗？我收到的行/列没有数据。＆＃39;这个错误抛出

Answer 1

您没有调用Read Method

    OleDbDataReader reader = command.ExecuteReader();
    if(reader.Read())
    {
       string result = reader.GetValue(0).ToString();
       MessageBox.Show(result);
     }
    connection.Close();

这只会从结果中读取第一行。如果你想要所有行，那么你需要写一些像这样的东西

    OleDbDataReader reader = command.ExecuteReader();        
    List<string> data = new List<string>();
    while(reader.Read())
    {
      data.Add(reader.GetValue(0).ToString());
    }        
    connection.Close();