running out of memory building massive string
byte[] bytes = File.ReadAllBytes(infile);

try
{
    StringBuilder sb = new StringBuilder(BitConverter.ToString(bytes)); // <--exception
    hexfield.Text = sb.ToString();
}

catch(Exception e)
{
    MessageBox.Show(e.ToString());
}

System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.
at System.String.CtorCharArrayStartLength(Char[] value, Int32 startIndex, Int32 length)
at System.BitConverter.ToString(Byte[] value, Int32 startIndex, Int32 length)
at System.BitConverter.ToString(Byte[] value)
 at shex.shexx.hexfield_Dragrop(Object sender, DragEventArgs e)**

StringBuilder b = new StringBuilder(bytes.Length * 3 - 1);
int pos = 0;
while (pos < bytes.Length - 1000) {
  b.Append(BitConverter.ToString(bytes, pos, 1000)).Append('-');
  pos += 1000;
}
b.Append(BitConverter.ToString(bytes, pos));
hexfield.Text = b.ToString();