Three part question regarding listboxes gridviews and file directories

Hi,

This is couple part question.

1) I have a listbox populated from the database, and I have a gridview populated from database.

Both listbox and a gridview have one common column.  I would like to programmatically highlight all the rows of the gridview to green if both listbox and gridview have that ID.

so I wrote this procedure:

public void highlight()
        {
            try
            {//this only works if I select a row from listbox. I need this for every row
                string projectano = lbinvoicenames.SelectedValue.ToString();

                foreach (DataGridViewRow row in gvinvoices.Rows)
                {
                    if (row.Cells[0].Value.ToString() != null)
                    {

                        if (projectano == row.Cells[0].Value.ToString())
                        {
                            counter = Convert.ToInt32( gvinvoices.selectedindex.ToString());
                            row.DefaultCellStyle.BackColor = Color.Green;

                            //gvinvoices.CurrentCell = gvinvoices.Rows[row.Index].Cells[0];

                        }
                        if (row.DefaultCellStyle.BackColor != Color.Green)
                        {
                           
                        }

                    }
                }
            }
            catch { }
        }

2) The second part of the question is if the row is not higlighted to green move them to the top.

3) And the last question. 

I read files from a directory and load them to a separate listbox.  My gridview contains a column with a unique number. That unique number is a part of the naming of the pdfs. I would like to be able to highlight the row of listbox with file name where unique number is the number from the gridview.

Any help?

Thank you,