Question

I’ve got a RichTextBox, and would like to highlight a whole word, given just its ending index. Is it possible to highlight from an ending index, backwards to the first occurance of a space?

This is what I’ve tried so far, but I don’t know if there is any other efficient methods:

int length = richTextBox.Text.Reverse().Skip(richTextBox.Text.Length - offset)
      .TakeWhile(x => x != ' ')
      .Count();
richTextBox.Select(offset - length, length + 1);
richTextBox.SelectionBackColor = Color.Yellow;

Answer 1

That’s a very inefficient way to get the length.

Try this- might be off by one somewhere, I cant test it right now:

var prevSpace = richTextBox.Text.LastIndexOf(' ', offset);
var length = prevSpace = -1 ? offset + 1 : offset - prevspace;