open a file by double click

//write connection to server
try
{
    if (dataGridView1.RowCount > 0)
    {
        DataGridViewRow row = dataGridView1.CurrentCell.OwningRow;
        document_type = row.Cells[7].Value.ToString();
        tag11 = row.Cells[1].Value.ToString();
        tag22 = row.Cells[2].Value.ToString();
        tag33 = row.Cells[3].Value.ToString();
        tag44 = row.Cells[4].Value.ToString();
        date1 = row.Cells[8].Value.ToString();

    }

    if (dataGridView2.RowCount > 0)
    {
        DataGridViewRow row = dataGridView1.CurrentCell.OwningRow;
        document_type = row.Cells[7].Value.ToString();
    }

    if (
        document_type == "Image"
        || document_type == "Pdf Document"
        || document_type == "Audio"
        || document_type == "Video"
        || document_type == "Text"
    )
    {
        DocumentView view = new DocumentView(documentname);
        view.ShowDialog();
        view_count();
    }
    else
    {
        int lng = Application.ExecutablePath.Length; ;
        int lng2 = lng - 18;
        string pth = Application.ExecutablePath.Substring(0, lng2);
        string destinationfolder = pth + "Documents";
        string save_path1 = destinationfolder + @"\" + documentname;
        System.Diagnostics.Process.Start(save_path1);
    }
}
catch (Exception e3)
{
    int lng = Application.ExecutablePath.Length; ;
    int lng2 = lng - 18;
    string pth = Application.ExecutablePath.Substring(0, lng2);
    string destinationfolder = pth + "Documents";
    string save_path1 = destinationfolder + @"\" + documentname;
    MessageBox.Show("System Or Windows can not open the Selected Document");
    System.IO.StreamReader sr = new
    System.IO.StreamReader(save_path1);
    MessageBox.Show(sr.ReadToEnd());
    sr.Close();
}