How to show the message and redirect to other page in ASP.NET

// Method 1

ScriptManager.RegisterStartupScript(this, this.GetType(), "redirect", "alert('Alert Message'); window.location='" + Request.ApplicationPath + "Nextpage.aspx';", true);

// Method 2

Response.Write("<script>alert('Alert Message')</script>");

Response.Write("<script>window.location.href='" + Request.ApplicationPath + "Nextpage.aspx" + "';</script>");