[C#] Builder and stub

[Bman]

Builder :

string filepath = string.Empty;
    SaveFileDialog saveDlg = new SaveFileDialog();
    {
    saveDlg.FileName = "Server.exe";
    saveDlg.Filter = "Executable Files (*.exe)|*.exe";

    if (saveDlg.ShowDialog() == DialogResult.OK)
    filepath = saveDlg.FileName;
    else
    return;
    }
    File.Copy(Application.StartupPath+@"\stub.exe", filepath);

    string split = "-whatever-";
    string info = split + txtWhatever.text +
    split;

    FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.ReadWrite, FileShare.None);
    {    
    BinaryWriter bw = new BinaryWriter(fs);
    fs.Position = fs.Length + 1;
    bw.Write(info);
    bw.Close();
    }

Stub : (Split string if more needed)

StreamReader sr = new StreamReader(System.Windows.Forms.Application.ExecutablePath);
    BinaryReader br = new BinaryReader(sr.BaseStream);

    byte[] fileData = br.ReadBytes(Convert.ToInt32(sr.BaseStream.Length));
    br.Close();
    sr.Close();

    ASCIIEncoding Conv = new ASCIIEncoding();

    string whatever = Conv.GetString(fileData).Substring(Conv.GetString(fileData).IndexOf("-whatever-")).Replace("-whatever-", "");