SqlCeConnection con = new SqlCeConnection("Data Source = D:\\Diagnostic\\Debug\\obd.sdf");
con.Open();
SqlCeDataAdapter sda = new SqlCeDataAdapter("select ID from Test", con);
sda.Fill(_MyDatabase_1DataSet);
this.dataGrid1.DataSource = _MyDatabase_1DataSet.Tables[0];
con.Close();
con.Dispose();
return CString();
}
using System.Data.SqlServerCe;这个前面已经加了