how to use the dataGridView inside timer

Quote:

When I clicked the start button "downloadFile" Array sometimes cannot be clear can someone fix this code where is my problem

List<string[]> downloadingSite = new List<string[]>();

private void button_Start_Click(object sender, EventArgs e)
{
    timer1.Start();
    timer1.Interval = 1500;
}

private void timer1_Tick(object sender, EventArgs e)
{
     if (Program.downloadingFile[0] != "" && Program.downloadingFile[0] != null)
            {
                dataGridReport.Rows.Add("Complete",
                                        downloadingFile[0],
                                        downloadingFile[1],
                                        progressPrecentage,
                                        downloadingFile[2],
                                        downloadingFile[3]);
               Array.Clear(downloadingFile, 0, downloadingFile.Length);
            }
}