binary formatter to string

Question

    BinaryFormatter formatter = new BinaryFormatter();

    using (MemoryStream m = new MemoryStream())
    {
        formatter.Serialize(m, list);
        StreamReader sr = new StreamReader(m);
        HiddenField1.Value = sr.ReadToEnd();
    }

i'm getting a blank value for HiddenField1.Value. Not sure what I'm doing is even possible? list is definitely populated (is a List<T>)

Answer 1

Depending on what you want to achieve... One option is to show content of the binary stream as Base64 string:

var memoryStream = new MemoryStream();
using(memoryStream)
{
    formatter.Serialize(memoryStream, list);
}
HiddenField1.Value = Convert.ToBase64String(memoryStream.ToArray());

Answer 2

Change it to:

BinaryFormatter formatter = new BinaryFormatter();

using (MemoryStream m = new MemoryStream())
{
    formatter.Serialize(m, list);
    m.Position = 0;
    StreamReader sr = new StreamReader(m);
    HiddenField1.Value = sr.ReadToEnd();
}

You need to reset the position of the stream back to the beginning before reading it. Also, you shouldn't use StreamReader to convert a binary stream like this to text, because it will break in unexpected ways. If you want the results in a text-like format, use Convert.ToBase64String as in @Alexei's answer.