Check if selected text on richtextbox is all bold or not

Question

How to check if selected text on richtextbox is all bold. For example:

asdasdasdasd ← this is not all bold
Im all bold ← this is all bold

This is the code I have made, it can check if its all bold or not but its slow because its checking the char one by one using Selection.Start to Selection.Length and check if bold.

bool allbold = true;
int start = richTextBox1.SelectionStart;
int end = richTextBox1.SelectionLength;
for (int i = 1; i < end; i++)
{
    richTextBox1.SelectionStart = start+i;
    richTextBox1.SelectionLength = 1;
    if (!richTextBox1.SelectionFont.Bold)
    {
        allbold = false;
        richTextBox1.SelectionStart = 0;
        richTextBox1.SelectionLength = 0;
        richTextBox1.SelectionStart = start;
        richTextBox1.SelectionLength = end;
        richTextBox1.Focus();
    }
}

Is there any efficient way than this?

Answer 1

You can check richTextBox1.SelectionFont.Bold. It returns true if all selected text is bold.

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To test, it's enough to initialize RichTextBox with such value:

richTextBox1.SelectedRtf = @"{\rtf1\fbidis\ansi\ansicpg1256\deff0" +
    @"\deflang1065{\fonttbl{\f0\fnil\fcharset0 Calibri;}}\uc1\pard\ltrpar" +
    @"\lang9\b\f0\fs72 T\fs22 his\b0  \b i\b0 s a \b t\b0 est.}";

Then check different selection this way:

if (richTextBox1.SelectionFont != null)
    MessageBox.Show(string.Format("{0}", richTextBox1.SelectionFont.Bold));