Rich Text Box - Line Numbers

[Jeff Gaines]

I want to show line numbers in a control which is derived from a WinForms
RTB control. I am using:

private void SetLineNumbers()
{
PARAFORMAT2 paraFormat = new PARAFORMAT2();

paraFormat.cbSize = (UInt32)Marshal.SizeOf(paraFormat);

// Get existing format
SendMessage(this.Handle, EM.EM_GETPARAFORMAT, 0, ref paraFormat);

// Set flags
paraFormat.dwMask = (int)(PFM.PFM_NUMBERING | PFM.PFM_NUMBERINGSTYLE |
PFM.PFM_NUMBERINGSTART);
paraFormat.wNumbering = (UInt16)NUMBERING.Arabic;
paraFormat.wNumberingStart = 0;
paraFormat.wNumberingStyle = (UInt16)NUMBERINGSTYLES.NumberOnly;

SendMessage(this.Handle, EM.EM_SETPARAFORMAT, 0, ref paraFormat);
}

It works to the extent that I do get line numbers in theleft margin but
they stop at 254. If I paste text in then 254 is just repeated for all the
higher lines, if I type lines in I just get a blank.

Is there a way round this?

I have looked at some custom RTBs on the Internet and they seem to use
lables or panels to the left of the RTB. I have alos looked at the Sharp
Edit source but that is massive overkill for what I want.

Would appreciate any guidance.

[Herfried K. Wagner [MVP]]

Post by Jeff Gaines
I want to show line numbers in a control which is derived from a
private void SetLineNumbers()
{
PARAFORMAT2 paraFormat = new PARAFORMAT2();
paraFormat.cbSize = (UInt32)Marshal.SizeOf(paraFormat);
// Get existing format
SendMessage(this.Handle, EM.EM_GETPARAFORMAT, 0, ref paraFormat);
// Set flags
paraFormat.dwMask = (int)(PFM.PFM_NUMBERING | PFM.PFM_NUMBERINGSTYLE |
PFM.PFM_NUMBERINGSTART);
paraFormat.wNumbering = (UInt16)NUMBERING.Arabic;
paraFormat.wNumberingStart = 0;
paraFormat.wNumberingStyle = (UInt16)NUMBERINGSTYLES.NumberOnly;
SendMessage(this.Handle, EM.EM_SETPARAFORMAT, 0, ref paraFormat);
}
It works to the extent that I do get line numbers in theleft margin but
they stop at 254. If I paste text in then 254 is just repeated for all
the higher lines, if I type lines in I just get a blank.
Is there a way round this?

I doubt that there is an easy way around that using the approach you
have chosen. Paragraph numbering is typically used to create numbered
/lists/.

Post by Jeff Gaines
I have looked at some custom RTBs on the Internet and they seem to use
lables or panels to the left of the RTB.

I assume that those are better approaches.

[Jeff Gaines]

Post by Herfried K. Wagner [MVP]
I assume that those are better approaches.

Horribly complicated just to get line numbers but seems like the only way.

Many thanks Herfried :-)