open a document in browser

Question

string filename = "1.docx";

string filepath= @"......\1.docx";

Response.Clear();

Response.AddHeader("content-disposition","attachment;filename=" + filename);

Response.ContentType = "application/force-download";

Response.WriteFile(filepath);

Response.Flush();

Response.End();

 I used this code for opening the document in page load event but it's not showing rather than downloading i want a preview of the document please help me