ScanMaster.GUI.ControllerWindow.KeyUpHandler C# (CSharp) Method

        private void KeyUpHandler(object sender, System.Windows.Forms.KeyEventArgs e)
        {
            // if enter is pressed we should process the command
            if (e.KeyData == Keys.Enter)
            {
                String command = commandTextBox.Text;
                commands.Add(command);
                commandMarker = commands.Count;
                commandTextBox.Clear();
                // echo the command
                WriteLine(Prompt + command);
                lock(this)
                {
                    latestLine = command;
                    newLineAvailable = true;
                }

            }
            // if up is pressed return the previous command in the list in the usual way
            if (e.KeyData == Keys.Up)
            {
                commandMarker--;
                if (commandMarker<0) commandMarker = 0;
                commandTextBox.Clear();
                commandTextBox.Text= commands[commandMarker];
                commandTextBox.Select(commandTextBox.Text.Length,0);
            }

            // if down is pressed return the next command in the usual way
            if (e.KeyData == Keys.Down)
            {
                commandMarker++;
                if (commandMarker > commands.Count) commandMarker = commands.Count;
                commandTextBox.Clear();
                if (commandMarker == commands.Count)
                {
                }
                else
                {
                    commandTextBox.Text = commands[commandMarker];
                    commandTextBox.Select(commandTextBox.Text.Length, 0);
                }
            }

            // tab attempts to autocomplete the command
            if (e.KeyData == Keys.Tab)
            {
                String[] suggestions = manager.Processor.GetCommandSuggestions(commandTextBox.Text);
                if (suggestions == null) return;
                if (suggestions.Length == 1)
                {
                    commandTextBox.Text = suggestions[0] + " ";
                    commandTextBox.SelectionStart = commandTextBox.Text.Length;
                    return;
                }
                StringBuilder sb = new StringBuilder();
                foreach (String s in suggestions) sb.Append(s + "\t");
                sb.Append(Environment.NewLine);
                WriteLine(sb.ToString());
            }

            // escape clears the current text
            if (e.KeyData == Keys.Escape) commandTextBox.Clear();
        }