из OleDbCommand получить DataTable

		// function for fill DataTable from DataReader!!!PK mast be the fist columns!!!
		virtual protected DataTable GetTableFromReader(OleDbDataReader dr,int first_pk_amount)
		{
			if(dr==null) return null;
			//create table
			string[] Names = new String[dr.FieldCount];
			DataTable dt = new DataTable();
			for(int i=0;i<dr.FieldCount;i++)
			{
				dt.Columns.Add(dr.GetName(i),dr.GetType());
				Names[i] = dr.GetName(i);
			}
			//define primary keys
			if(first_pk_amount>0)
			{
				DataColumn[] keys = new DataColumn[first_pk_amount];
				for(int i=0;i<first_pk_amount;i++)
					keys[i] = dt.Columns[i];
			}
			//fill table
			DataRow drow;
			dt.BeginLoadData();
			while(dr.Read())
			{
				drow = dt.NewRow();
				drow.BeginEdit();
				for(int i=0;i<dr.FieldCount;i++)
				 drow[i] = dr.GetValue(i);
				drow.EndEdit();
				dt.Rows.Add(drow);
			}
			dt.EndLoadData();
			return dt;
		}

OleDbCommand cmd = new OleDbCommand();
// Иницализация вашей команды
OleDbDataAdapter da = new System.Data.OleDb.OleDbDataAdapter(cmd);
DataTable dt = new DataTable();
da.Fill(dt);