How to get/read File Contents of FileUpload1.PostedFile

Hi, I have to allow user to upload a file. Now internally, When user uploads a file using my FileUpload control, when user press Submit Button,

I have to read this file contents, Pass this File Name and File Contents to my Webservice's Webmethod and from Webmethod, I am sending Email.

I donot want to store this file anywhere on Server, I want to use MemoryStream.

Now, first of all my main problem is How to read contents of the file that is selected using FileUpload Control? Without saving it on server? If I am able to get file contents as string, that will be easy for me to pass this string to my WebMethod and then I can generate Attachment from MemoryStream.

So can you tell me How can I get/read uploaded file contents on my webform when user press submit button? 

 
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