Checking All CheckBoxes in a DatagridView

Basically I have a datagridview that shows some information on an order and I want to check the box I want to print.  So when I hit my print button it will check all the rows that are selected and print them...

The problem I am having is figuring out how to select all.  What I want to do it select the Header Text at the top of the column and when i click that withthe mouse it will make the checkboxes in its column all set to checked

Here is how I added the checkbox to the datagridview


 Private Sub addSelectedForPrintingColumn()
        Dim column As New DataGridViewCheckBoxColumn()
        With column
            .HeaderText = "For Printing"
            .Name = "colSelectForPrinting"
            .Width = 110

            .FlatStyle = FlatStyle.Standard
            .CellTemplate = New DataGridViewCheckBoxCell()
            .CellTemplate.Style.BackColor = Color.Blue


        End With

        dgvDocketInformation.Columns.Insert(0, column)
    End Sub