怎么把两个OleDbDataAdapter 合并到一个DataTable

public OleDbDataAdapter FindForMdb(string mdbpath,string sql)
        {
            string connstr = "Provider = Microsoft.Jet.OLEDB.4.0; Data Source =" + mdbpath;
            OleDbConnection conn = new OleDbConnection(connstr);
            return new OleDbDataAdapter(sql, conn);
        }
private void btnFind_Click(object sender, EventArgs e)
        {
            string sql = txtFind.Text;
            int dataCount = GetMDBCount();
            OleDbDataAdapter da;
            System.Data.DataTable dt = new System.Data.DataTable();
            for (int i = 1; i < dataCount; i++)
            {
                string path = System.Windows.Forms.Application.StartupPath + "\\data" + i.ToString() + ".mdb";
                da=FindForMdb(path, sql);
                da.Fill(dt);
            }
            dataGridView1.DataSource = dt;
        }