Cannot redirect after http headers have been sent

Hello
I am getting this error Message "cannot redirect after http headers have been sent"
when I am calling response.redirect ("home.aspx").
this error occured after downloading file from gridview which is infragistic control.following code to downloading file..
so how can i redirect to the page.

string fileName=this.Controller.Model.SessionDataContext.FileAttachmentRowData.PhysicalFileName;
  byte[] array = this.Controller.Model.SessionDataContext.FileAttachmentRowData.FileContents;
  Response.Clear();
  Response.Buffer = true;
  Response.AddHeader("Content-disposition", "attachment; filename=" + fileName);
  Response.AddHeader("Content-Length", array.Length.ToString());
  Response.ContentType = "application/pdf";
  Response.OutputStream.Write(array, 0, array.Length);
  Response.Flush();
  Response.Clear();