C# – RichTextBox does not constantly update when used as text status display

crichtextboxtextboxwinforms

I'm trying to use a RichTextBox as a status display but it is not updating every time I append to the text of the RichTextBox. A regular multiline TextBox will update everytime new text is appended to it, but I would prefer to use the RichTextBox. Is there some sort of property that needs to be set to see the updates?

UPDATE:
Also, how would I automatically make it scroll down every a message is displayed?

Like I said, if I replace the RichTextBox with a TextBox, I can see each line of the messages as they are getting written out and it will also automatically scroll down to the bottom to display the latest text added.

void UpdateStatus(string textMessage)
{
  if (InvokeRequired)
  {
    BeginInvoke(new MethodInvoker(() => UpdateStatus(textMessage)));
    return;
  }

  richTextBox.AppendText(textMessage + Environment.NewLine);
}

Best Answer

An easy and quick fix would be

Application.DoEvents()

Related Solutions

C# – displaying line number in rich text box c#

My own example. All is fine, but wordwrap must be disabled :(

    int maxLC = 1; //maxLineCount - should be public
    private void rTB_KeyUp(object sender, KeyEventArgs e)
    {
        int linecount = rTB.GetLineFromCharIndex( rTB.TextLength ) + 1;
        if (linecount != maxLC)
        {
            tB_line.Clear();
            for (int i = 1; i < linecount+1; i++)
            {
                tB_line.AppendText(Convert.ToString(i) + "\n");
            }
            maxLC = linecount;
        }
    }

where rTB is my richtextbox and tB is textBox next to rTB

J.T. jr

C# – How to automatically scroll to the bottom of a multiline text box

At regular intervals, I am adding new lines of text to it. I would like the textbox to automatically scroll to the bottom-most entry (the newest one) whenever a new line is added.

If you use TextBox.AppendText(string text), it will automatically scroll to the end of the newly appended text. It avoids the flickering scrollbar if you're calling it in a loop.

It also happens to be an order of magnitude faster than concatenating onto the .Text property. Though that might depend on how often you're calling it; I was testing with a tight loop.

This will not scroll if it is called before the textbox is shown, or if the textbox is otherwise not visible (e.g. in a different tab of a TabPanel). See TextBox.AppendText() not autoscrolling. This may or may not be important, depending on if you require autoscroll when the user can't see the textbox.

It seems that the alternative method from the other answers also don't work in this case. One way around it is to perform additional scrolling on the VisibleChanged event:

textBox.VisibleChanged += (sender, e) =>
{
    if (textBox.Visible)
    {
        textBox.SelectionStart = textBox.TextLength;
        textBox.ScrollToCaret();
    }
};

Internally, AppendText does something like this:

textBox.Select(textBox.TextLength + 1, 0);
textBox.SelectedText = textToAppend;

But there should be no reason to do it manually.

^{(If you decompile it yourself, you'll see that it uses some possibly more efficient internal methods, and has what seems to be a minor special case.)}

Best Answer

Related Solutions

C# – displaying line number in rich text box c#

C# – How to automatically scroll to the bottom of a multiline text box

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