`ContentType`

This property sets an HTTP header—it is useful when sending a response that is not HTML. By using ContentType we change the HTTP header for the response.

Server headers

So when you set the ContentType property, how does this affect the HTTP headers sent by IIS? We will see this header being sent: "Content-Type: text/plain".

Example

Here the Application_BeginRequest event handler is defined. In Application_BeginRequest, we acquire the HttpResponse, and then assign the ContentType property to "text/plain".

Finally We write some characters with the Response.Write method and call CompleteRequest.

using System;
using System.Web;

namespace WebApplication1
{
    public class Global : HttpApplication
    {
        void Application_BeginRequest(object sender, EventArgs e)
        {
            // Get response.
            HttpResponse response = base.Response;

            // Set ContentType.
            response.ContentType = "text/plain";

            // Write string.
            response.Write("PLAIN TEXT");

            // Complete request.
            base.CompleteRequest();
        }
    }
}

Page output

When this is executed successfully, you will see a plain text page in your web browser with the PLAIN TEXT in monospaced font.

Note Browsers will read this header and then display your page as a plain text document, not HTML.

A summary

We sent a different Content-Type HTTP header in the ASP.NET environment. By assigning to the ContentType property, the response will be sent with your specified value.