C# Winform: Textbox can only capture most control characters, but not E, J, L, or R

I have a textbox in C# which, upon a KeyDown event, fires off to a method that outputs comprehensive keyboard input data.  (This is as a test for creating shortcuts that do various actions).

For most control key sequences, it works this way:  the user has focus on the textbox, and if you tap the control key, the following output will display:

checkForShortcuts():  KeyCode == ['ControlKey'], KeyValue == [17], KeyData == [ControlKey, Control], kKey == [ControlKey], cKey == '<' (17).

(I have substituted '<' in the above output statement for character 17, which looks like a left pointing triangle.)

If you type  a Control-T, it will show this:

checkForShortcuts():  KeyCode == ['ControlKey'], KeyValue == [17], KeyData == [ControlKey, Control], kKey == [ControlKey], cKey == '<' (17).
checkForShortcuts():  KeyCode == ['T'], KeyValue == [84], KeyData == [T, Control], kKey == [T], cKey == 'T' (84).

(There are two lines because I hold down the control key before pressing T, sometimes if I just wait I will get a whole slew of outputs about the control key being pressed.)


The problem:

The problem is that there are a few control keys that simply do not fire that I'd like to use.

They are:

^E, ^J, ^L, and ^R.

(Also, ^A will not fire but instead issue a Select All, however, this is desired functionality.)


QUESTION:  How can I capture these other control characters?  This should be a very simple and obvious thing to do.


Also:
Since this is .NET (4.0), I'm just using all the defaults in Visual Studio (2010).  The essential code is:

        protected void checkForShortcuts(TextBoxBase tbb, KeyEventArgs e)
        {
            Keys kKey = e.KeyCode;
            char cKey = char.ToUpper ( (char)e.KeyValue );
            
            rtbOutput.AppendText( string.Format(
                    "checkForShortcuts():  KeyCode == ['{0}'], KeyValue == [{1}], KeyData == [{2}], kKey == [{3}], cKey == '{4}' ({5})."
                    + Environment.NewLine, e.KeyCode, e.KeyValue, e.KeyData, kKey, cKey, (int) cKey) );

        // ...

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