2 Warning on Debugging

private void button1_Click_1(object sender, EventArgs e)
        {
            Microsoft.Office.Interop.Word.Application app = new Microsoft.Office.Interop.Word.ApplicationClass();
            object nullobj = System.Reflection.Missing.Value;
            object file = @"C:\1.doc";

            Microsoft.Office.Interop.Word.Document doc = app.Documents.Open(
            ref file, ref nullobj, ref nullobj,
            ref nullobj, ref nullobj, ref nullobj,
            ref nullobj, ref nullobj, ref nullobj,
            ref nullobj, ref nullobj, ref nullobj,
            ref nullobj, ref nullobj, ref nullobj, ref nullobj);
            doc.ActiveWindow.Selection.WholeStory();
            doc.ActiveWindow.Selection.Copy();
            IDataObject data = Clipboard.GetDataObject();
            string text = data.GetData(DataFormats.Text).ToString();
            MessageBox.Show(text);
            doc.Close(ref nullobj, ref nullobj, ref nullobj);
            app.Quit(ref nullobj, ref nullobj, ref nullobj);

            textBox1.Text = text;
        }