vb.net - Multicolor RichTextBox - vb.net

Question

I would like to make a line of text in my richtextbox multicolor. I have tried various implementations provided on the web and read up on SelectedText and other topics but can't seem to get it to work the way I would like to.
Here is what I have so far
RichTextBox1.Text = "This is black "
RichTextBox1.SelectionFont = New Font("Microsoft Sans Serif", 8.25, FontStyle.Bold)
RichTextBox1.SelectionColor = Color.Green
RichTextBox1.SelectedText = "[BOLD GREEN]"
RichTextBox1.Text = RichTextBox1.Text + " black again"
The colors I want are stated as the text. What happens is: the entire line turns green, "[BOLD GREEN]" appears at the beginning of the textbox instead of inline.
I want it to read like this: "this is black" as black. "[BOLD GREEN]" as green and "black again" as black.

Answer 1

It's not really clear what you're trying to achieve. I'm not sure I understand the bracketed formatting nearly as well as I would an image that you mocked up in Paint. But here goes anyway...
I suspect there are a couple of problems with your existing code. First up is the location of the cursor when you insert new text. What's supposed to come after the first snippet actually gets inserted before it because of where the insertion mark is located. To fix that, you need to move it manually.
You're also assigning a string of text to the Text property at the end of your code, which does not preserve the existing formatting information. I suspect that the simplest thing for you to do is to use the AppendText method, instead.
And finally, I recommend using the simpler overload to create a new font, since the only thing you want to change is the style. The advantage of using this instead is that you don't have to hardcode the name and size of the font in your code, in case you want to change it later.
Try rewriting your code to this instead:
' Insert first snippet of text, with default formatting
RichTextBox1.Text = "This is black "
' Move the insertion point to the end of the line
RichTextBox1.Select(RichTextBox1.TextLength, 0)
'Set the formatting and insert the second snippet of text
RichTextBox1.SelectionFont = New Font(RichTextBox1.Font, FontStyle.Bold)
RichTextBox1.SelectionColor = Color.Green
RichTextBox1.AppendText("[BOLD GREEN]")
' Revert the formatting back to the defaults, and add the third snippet of text
RichTextBox1.SelectionFont = RichTextBox1.Font
RichTextBox1.SelectionColor = RichTextBox1.ForeColor
RichTextBox1.AppendText(" black again")
The result will look like this: