Set/Unset Italic in RichTextBox

Question

I have a RTF box in my C# WinForms app.

Setting basic styles is fairly simple but when I try to unset the Italic style I lose all other applied styles to the selection font.

if (rtf.SelectionFont.Style.HasFlag(FontStyle.Italic))
{
     rtf.SelectionFont = new Font(rtf.SelectionFont.FontFamily, rtf.SelectionFont.Size, rtf.SelectionFont.Style | FontStyle.Regular);
}
else
{
     rtf.SelectionFont = new Font(rtf.SelectionFont.FontFamily, rtf.SelectionFont.Size, rtf.SelectionFont.Style | FontStyle.Italic);
}

Is there a way to just de-select the italic property without losing the Bold,underline ect.

Answer 1

Use an XOR rather than an OR to remove a single FontStyle - for example:

private void btnBold_Click(object sender, EventArgs e)
{
    var currentStyle = rtf.SelectionFont.Style;
    var newStyle =
        rtf.SelectionFont.Bold ?
        currentStyle ^ FontStyle.Bold :
        currentStyle | FontStyle.Bold;

    rtf.SelectionFont =
        new Font(
            rtf.SelectionFont.FontFamily,
            rtf.SelectionFont.Size,
            newStyle);
}

private void btnItalic_Click(object sender, EventArgs e)
{
    var currentStyle = rtf.SelectionFont.Style;
    var newStyle =
        rtf.SelectionFont.Italic ?
        currentStyle ^ FontStyle.Italic :
        currentStyle | FontStyle.Italic;

    rtf.SelectionFont =
        new Font(
            rtf.SelectionFont.FontFamily,
            rtf.SelectionFont.Size,
            newStyle);
}

With this implementation, removing the bold or italic style will not affect the other style if it is already applied to the selection.

BONUS:

For additional considerations like reselecting the selection after changing its style, an old DevX tip of the day might interest you too.

Also, the common logic in the style-specific handlers I offered begs to be factored out into a helper method that the style-specific handlers can leverage - e.g. private ChangeStyle(FontStyle style).

Answer 2

You should try iterating over the enumeration and putting the style back together. Something like the following:

FontStyle oldStyle = rtf.SelectionFont.Style;
FontStyle newStyle = FontStyle.Regular;
foreach (Enum value in Enum.GetValues(oldStyle.GetType()))
{
    if (oldStyle.HasFlag(value) && !value.Equals(FontStyle.Italic))
    {
        newStyle = newStyle | (FontStyle)value;
    }
}

rtf.SelectionFont = new Font(rtf.SelectionFont.FontFamily, rtf.SelectionFont.Size, newStyle);