accessing controls of one form in another form

[C# Programming]

i am working with mutiple forms, i want to update the DataGridView of form2 in form3,DAtaGridView gets the table from the data base, i want to update the DataGridView which is in Form2. but cant update it from Form3.DataGridView is not accessable in Form3.
plzzzzzzzzzz help me out.
thanx in advance.