.NET Windows.Forms: How can I reverse all strings in text boxes whenever one of them changes?

Question

I wrote a program that accepts and outputs Hebrew (i.e. right-to-left) text.

In lieu of a Hebrew keyboard, the program has 22 buttons that allow the typing of Hebrew letters into one of the text boxes. (This has nothing to do with the problem, I think.)

This program works fine under Windows using Microsoft .NET and Mono.

However, in Mac OS X and Linux all Hebrew text is the wrong way around and typing Hebrew text also adds letters to the right of existing text rather than to the left.

I figure I can catch all "text changed" events of all text fields and reverse those strings before replacing the original textField.text with the new string. But since there are about 100 text fields on the form, this would be tiresome.

Is there a more general event I should use or another solution I overlooked?

(Testing for the underlying OS is easy since Mono returns a PlatformID of PlatformID.Unix on Mac OS X as well as Linux.)

Answer 1

Are you basically going to do the same thing for each text box? If so, write one method to do it, then hook it up to all the "text change" events by filtering the Controls collection to just TextBoxes, e.g. with Controls.OfType<TextBox>().

Use the "sender" parameter to work out which text box you're interested in. Shouldn't be too hard:

foreach (TextBox tb in Controls.OfType<TextBox>())
{
    tb.TextChanged += ReverseText;
}
...

private static void ReverseText(object sender, EventArgs e)
{
    TextBox tb = (TextBox) sender;
    tb.Text = ReverseText(tb.Text);
}

(You'd then need to write ReverseText, but I assume you already have this. Calling ToCharArray and reversing the contents is a simple way of doing it, but may have issues for you in terms of combining characters etc.)

Answer 2

You could loop through all the textboxes adding an event to the text changed events

Answer 3

You could create your own text box inheriting from the WinForms textbox.

Answer 4

If you are getting PlatformID.Unix on OSX, then you are using an old version of Mono. Try updating first. Then, if the text rendering is still broken, file a bug with Mono. Workarounds will break when this bug gets noticed and fixed.