intercepting the open and save as buttons

 private void RadForm1_Load(object sender, EventArgs e)
        {
            CommandBarButton btn = new CommandBarButton();
            this.radPdfViewerNavigator1.CommandBarElement.Rows[0].Strips[0].Items.Insert(4,btn);
            btn.SvgImage = this.radPdfViewerNavigator1.SaveButton.SvgImage;
            btn.SvgImage.Size = this.radPdfViewerNavigator1.SaveButton.SvgImage.Size;
            btn.Click+=btn_Click; 

           this.radPdfViewerNavigator1.CommandBarElement.Rows[0].Strips[0].Items.Remove(this.radPdfViewerNavigator1.SaveButton);
        }

        private void btn_Click(object sender, EventArgs e)
        {
            SaveFileDialog savefile = new SaveFileDialog(); 
            savefile.Filter = "PDF files (*.pdf)|*.pdf|All files (*.*)|*.*";

            if (savefile.ShowDialog() == DialogResult.OK)
            {
                this.radPdfViewer1.PdfViewerElement.SaveDocument(savefile.FileName);
            }
        }