PDF Save in Attachment

Controller Code:
public void showPDF() { PageReference savePDF= new PageReference('/apex/ProposalPdf?id='+apexpages.currentpage().getparameters().get('id')); Blob pdfBlob = savePDF.getContent(); Attachment saveAtch = new Attachment(ParentId = apexpages.currentpage().getparameters().get('id'), Name = prop.Name+'.pdf' , ContentType = 'pdf', Body = pdfBlob); insert saveAtch; }