Reg: Loading text file(size 100 MB) in Richtextbox

Question

Hi,
        I am trying to load 100 MB of Text file in rich text box, but the application gets hang  or some times it gives out of memory exception. 
I tried below

Case1: it is running for long time

fs = new FileStream(FileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);

                sr = new StreamReader(fs);

                //rtxtFile.AppendText( sr.ReadToEnd());

                while (!sr.EndOfStream)

                {

                    rtxtFile.AppendText(sr.ReadLine() + System.Environment.NewLine);

                }

Case2:  out of memory exception

fs = new FileStream(FileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);

                sr = new StreamReader(fs);

                rtxtFile.AppendText( sr.ReadToEnd());

        

anybody give the solution for the above problem;

with reagrds,
Vishnuvarthan.V