CSHARP

Base64String to stream c#

var bytes = Convert.FromBase64String(base64encodedstring);
var contents = new StreamContent(new MemoryStream(bytes));
// Whatever else needs to be done here.

convert stream to base64 string c#

You can also encode bytes to Base64. How to get this from a stream see here: How to convert an Stream into a byte[] in C#?

Or I think it should be also possible to use the .ToString() method and encode this.