System.Windows.Forms.HexBox.KeyInterpreter.PreProcessWmChar C# (CSharp) Method

            public virtual bool PreProcessWmChar(ref Message m)
            {
                if(Control.ModifierKeys == Keys.Control)
                {
                    return _hexBox.BasePreProcessMessage(ref m);
                }

                bool sw = _hexBox._byteProvider.SupportsWriteByte();
                bool si = _hexBox._byteProvider.SupportsInsertBytes();
                bool sd = _hexBox._byteProvider.SupportsDeleteBytes();

                long pos = _hexBox._bytePos;
                long sel = _hexBox._selectionLength;
                int cp = _hexBox._byteCharacterPos;

                if(
                    (!sw && pos != _hexBox._byteProvider.Length) ||
                    (!si && pos == _hexBox._byteProvider.Length))
                {
                    return _hexBox.BasePreProcessMessage(ref m);
                }

                char c = (char)m.WParam.ToInt32();

                if(Uri.IsHexDigit(c))
                {
                    if(RaiseKeyPress(c))
                        return true;

                    if(_hexBox.ReadOnly)
                        return true;

                    bool isInsertMode = (pos == _hexBox._byteProvider.Length);

                    // do insert when insertActive = true
                    if(!isInsertMode && si && _hexBox._insertActive && cp == 0)
                        isInsertMode = true;

                    if(sd && si	&& sel > 0)
                    {
                        _hexBox._byteProvider.DeleteBytes(pos, sel);
                        isInsertMode = true;
                        cp = 0;
                        _hexBox.SetPosition(pos, cp);
                    }

                    _hexBox.ReleaseSelection();

                    byte currentByte;
                    if(isInsertMode)
                        currentByte = 0;
                    else
                        currentByte = _hexBox._byteProvider.ReadByte(pos);

                    string sCb = currentByte.ToString("X", System.Threading.Thread.CurrentThread.CurrentCulture);
                    if(sCb.Length == 1)
                        sCb = "0" + sCb;

                    string sNewCb = c.ToString();
                    if(cp == 0)
                        sNewCb += sCb.Substring(1, 1);
                    else
                        sNewCb = sCb.Substring(0, 1) + sNewCb;
                    byte newcb = byte.Parse(sNewCb, System.Globalization.NumberStyles.AllowHexSpecifier, System.Threading.Thread.CurrentThread.CurrentCulture);
                    if(isInsertMode)
                        _hexBox._byteProvider.InsertBytes(pos, new byte[]{newcb});
                    else
                        _hexBox._byteProvider.WriteByte(pos, newcb);

                    PerformPosMoveRight();

                    _hexBox.Invalidate();
                    return true;
                }
                else
                {
                    return true;
                    //return _hexBox.BasePreProcessMessage(ref m);
                }
            }