displaying issue when switching between RTL and LTR in Win Form Rich Text Box

Question

I tried the same thing in both Win form and WPF form and seems this only happens in Win Form. Basically what's happening is that I have a RTB control in Win Form, and 2 buttons: RTL and LTR to adjust the alignment.

button1 clicked:

richTextBox1.RightToLeft = System.Windows.Forms.RightToLeft.Yes;

button2 clicked:

richTextBox1.RightToLeft = System.Windows.Forms.RightToLeft.No;

That's all I have. when I paste text into RTB and click on the RTL button, it left a big gap in RTB. I noticed this will ONLY happen if the scroll bar is presenting. if you resize the form, the gap will go away.

I tried everything I could but couldn't figure out why it's happening. I suspect it's a .NET bug, does anybody have any idea?

Answer 1

Try this workaround:

string text = richTextBox1.Text;
richTextBox1.Clear();
richTextBox1.RightToLeft = RightToLeft.Yes;
BeginInvoke( new Action( () => richTextBox1.Text = text ) );

Note that the formatting (fonts, colours) are not preserved when RightToLeft is changed at run-time (according to Documentation).

Answer 2

Hi youkebb,

I have made a test about what you put forward, the reply from Viorel might be useful to you. Also,

You  could also  try the code  below:

string txtRTF = richTextBox1.Rtf;
richTextBox1.Clear();
richTextBox1.RightToLeft=System.Windows.Forms.RightToLeft.Yes;
Application.DoEvents();
richTextBox1.Rtf = txtRTF;

If you have any further questions, please feel free to post in this forum.

Best regards,

Leo