Some Content Type for Downloading File

Here are some of the most common content types:

.htm, .html     Response.ContentType = "text/HTML";

.txt    Response.ContentType = "text/plain";

.doc, .rtf, .docx    Response.ContentType = "Application/msword";

.xls, .xlsx    Response.ContentType = "Application/x-msexcel";

.jpg, .jpeg    Response.ContentType = "image/jpeg";

.gif    Response.ContentType =  "image/GIF";

.pdf    Response.ContentType = "application/pdf";