datagridviewcombocell and accdb

You can code something like following to retrive data from accdb and binding datagridview.

string connectionString= @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=F:\YourDB.accdb";
string sql = "SELECT * FROM TableName";
OleDbConnection con = new OleDbConnection(connectionString);
OleDbCommand cmd = new OleDbCommand(sql, con);
con.Open();
cmd.CommandType = CommandType.Text;
OleDbDataAdapter da = new OleDbDataAdapter(cmd);
DataTable dt= new DataTable();
da.Fill(dt);
YourDataGridviewId.DataSource = dt;

Now for adding values to comboboxcells you can write something like-

DataGridViewComboBoxCell cbCell = (DataGridViewComboBoxCell)myDataGrid.Rows[0].Cells[0];
cbCell.DataSource = dataSourceForCombobox; //get the datasource for combobox prior to this
cbCell.ValueMember = "ValueField";
cbCell.DisplayMember = "DisplayField";

You can make use of OnItemDataBound, to apply this for all the rows.

Hope, it helps :)