how to get the fontsize of a certain line in a richtextbox in c# using winforms

Question

I have 2 comboboxes for the font and the fontsize. When I click them it changes the font size or the font in my richtextbox. Now I want it to work like in word. If the line you just moved to is in a different font or size. It should detect that and change the comboxes to match the font and size of the current line. Somoeone else asked this same question and got a result which didn't work for me. It was as follows

    private void richTextBox1_SelectionChanged(object sender, EventArgs e)
    {
        MessageBox.Show("we got here"); // this is my added part to let me know if the code is even getting executed. It is not.
        richTextBox1.SelectionStart = 1;
        richTextBox1.SelectionLength = 1;
        comboBox1.Text = richTextBox1.SelectionFont.ToString();
        comboBox2.Text = null;
        comboBox2.Text = richTextBox1.SelectionFont.Size.ToString();

    }

I held out hope that it was my answer but I could not see how SelectionFont would make any difference when nothing was selected. Also the richTextBox1_SelectionChanged event seems to not be being called when I move through the document with the up/down arrows. The problem is not with the comboboxes, the problem is that as I arrow through my document I need to be able to know what font and size it is at the caret position so it can fire an event to change the combo boxes to match.

Answer 1

The code that you are using will always make the selection from character at index 1 and are of the length 1 . instead for that you need to use which will give you the the following code without specifying the selection(so it will take the selection from the ritchTextBox).

string fontName = richTextBox1.SelectionFont.Name;
float fontsize = richTextBox1.SelectionFont.Size;

Answer 2

You should save the values for the new comboBox position temporarily in variables, otherwise if you do it directly

comboBox1.SelectedIndex = comboBox1.FindStringExact(richTextBox1.SelectionFont.Name);

the comboBox1_SelectedIndexChanged event will be immediately called and could affect the results.

So just try:

private void richTextBox1_SelectionChanged(object sender, EventArgs e)
{
    int comboBox1Index = comboBox1.FindStringExact(richTextBox1.SelectionFont.Name);
    int comboBox2Index = comboBox2.FindStringExact(richTextBox1.SelectionFont.Size.ToString());

    comboBox1.SelectedIndex = comboBox1Index;
    comboBox2.SelectedIndex = comboBox2Index;
}

Answer 3

I adapted Sujith's solution and half of Markus's solution and came up with the following which works just fine for me:

Private Sub Description_SelectionChanged(sender As Object, e As EventArgs) Handles Description.SelectionChanged

    Dim fontName As String = Description.SelectionFont.Name
    Dim fontSize As Single = Description.SelectionFont.Size

    tbSelectFont.Text = fontName
    tbSelectSize.Text = fontSize

End Sub