C# :: Multiple Update Query After Filter In Datagridview

I'm new to c# and i'm using vs 2013 and access database..my i need to do multiple update records after I filtered the records in datagridview

In my database table I have these fields ID(PK/autonumber), EID,Date,Day,Daystatus..

In my form I have a button and it's fucntion is filter by date using bidingsource.fiter and this was the result

EID------Date-----------Day---Daystatus
10175--10/11/2014---sat--------regular
10176--10/11/2014---sat--------regular
10177--10/11/2014---sat--------regular
10178--10/11/2014---sat--------regular

what I want to happen is when I click another button called "Apply to all" I want to Update all the daystatus to "Legal Holiday" of the filtered records..I know how to update one by one using simple update..but I need to do the multiple update..

I tried to make a code but it was updating all the records not the filtered only here's my code:

try {
OleDbCommand command = new OleDbCommand();
connection.Open();
command.Connection = connection;
string query = "SELECT EID From EmployeeTable";
command.CommandText = query;
String a = "Legal Holiday";

[Code] ......