Opening a .pdf file in new window

On the First page write the following code:-

string Url = "Wite the url of the page to be opened"; 
ClientScript.RegisterStartupScript(this.GetType(), "", "window.open('" + Url + "');", true); 

On the second page (the page to be opened) write this on page load

  string path = "Wite path of the pdf file to be opened"; 
    WebClient client = new WebClient();  
    Byte[] buffer = client.DownloadData(path); 
    if (buffer != null) 
    { 
        Response.ContentType = "application/pdf";
        Response.AddHeader("content-length", buffer.Length.ToString()); 
        Response.BinaryWrite(buffer);
    }

Note :- Please import the namespace "using System.Net" to use WebClient.