c# DataGridView不显示数据

我有问题显示数据从访问数据库到我的datagridview。数据库中有两行。我错过了什么?

string strProvider = @"Provider=Microsoft.ACE.OLEDB.12.0;Data   Source=C:'Database'mydatabase.accdb;Persist Security Info=True";
    string strSql = "Select * from mytable";
    OleDbConnection con = new OleDbConnection(strProvider);
    OleDbCommand cmd = new OleDbCommand(strSql, con);
    con.Open();
    cmd.CommandType = CommandType.Text;
    OleDbDataAdapter da = new OleDbDataAdapter(cmd);
    DataTable scores = new DataTable();
    da.Fill(scores);
    data_grid_main.DataSource = scores;