How to add the Content-Length,Content-Type and Last-Modified to the HTTP Response Message Header

问题

How to add the Content-Length,Content-Type and Last-Modified to the HttpResponseMessage Header using .net.

I need to append the all these values manually to the response after adding these fields i need to return the response from the server. I have tried to adding these fields in fallowing way

httpResponse.Content.Headers.Add("Content-Length", item.Size.ToString());
httpResponse.Content.Headers.Add("Content-Type", item.ContentType);

But it throwing the exception as

"Object reference not set to an instance of an object".

If i am adding like this

httpResponse.Headers.Add("Content-Length", item.Size.ToString());
httpResponse.Headers.Add("Content-Type", item.ContentType);

I am getting the fallowing error

"Misused header name. Make sure request headers are used with HttpRequestMessage, response headers with HttpResponseMessage, and content headers with HttpContent objects."

Please any one help me to add these fields to the HttpResponsesMessage .

回答1:

You basically need to initialise Content first. For example:

var content = "this is some content";
var response = new HttpResponseMessage
{
    Content = new StringContent(content)
};
response.Content.Headers.Add(@"Content-Length", content.Length.ToString());

来源：https://stackoverflow.com/questions/22499258/how-to-add-the-content-length-content-type-and-last-modified-to-the-http-respons