Question

I want to write an application which sorts randomly line of text which I copy from a source and paste into RichTextBox area.

However, there is one condition – text is formatted (some words are in bold, underline etc.). So any suggestions? How should it look like?

I think I should use RichTextBox.Rtf or something but I am really a beginner and I appreciate every hint or example code.

Thanks

Answer 1

It is a bit tricky. You can retrieve the formatted RTF text lines like this

string[] rtfLines = new string[richTextBox1.Lines.Length];
for (int i = 0; i < rtfLines.Length; i++) {
    int start = richTextBox1.GetFirstCharIndexFromLine(i);
    int length = richTextBox1.Lines[i].Length;
    richTextBox1.Select(start, length);
    rtfLines[i] = richTextBox1.SelectedRtf;
}

Now you can shuffle the lines like this

var random = new Random();
rtfLines = rtfLines.OrderBy(s => random.NextDouble()).ToArray();

Clear the RichtTextBox

richTextBox1.Text = "";

Inserting the lines is best done in reverse order because it is easier to select the beginning of the text

// Insert the line which will be the last line.
richTextBox1.Select(0, 0);
richTextBox1.SelectedRtf = rtfLines[0];

// Prepend the other lines and add a line break.
for (int i = 1; i < rtfLines.Length; i++) {
    richTextBox1.Select(0, 0);

    // Replace the ending "}\r\n" with "\\par }\r\n". "\\par" is a line break.
    richTextBox1.SelectedRtf =
        rtfLines[i].Substring(0, rtfLines[i].Length - 3) + "\\par }\r\n";
}