Is there a way to determine if a form's text will fit in?

Question

Is there a way to determine if the form's text property will fit in the top bar using the form's current width (or if it will be truncated with "...")?

Answer 1

You might take a look into TextRenderer.MeasureText().

To calculate the width of a caption text use this snippet:

var width = TextRenderer.MeasureText(caption, SystemFonts.CaptionFont).Width;

You could use the size of your Form, subtract a fixed value for the icon (if visible) and the buttons on the top right (depends on the OS version and on the visible state of the [Minimize] [Maximize] buttons) and check if it is still positive. This might not give you a perfectly accurate result, but it is probably the simplest approximation.

So far, this method seems to calculate a pretty accurate approximation:

/// <summary>
/// Calculates an approximation of the available caption width
/// Depends on OS and theme
/// </summary>
/// <returns>Width</returns>
private int CalcAvaliableCaptionWidth()
{
    return
    // Form width
    Width
    // Icon
    - (Icon == null ? 0 : Icon.Width)
    // Minimize button (26 on Win8)
    - (MinimizeBox ? SystemInformation.CaptionButtonSize.Width : 0)
    // Maximize button (26 on Win8)
    - (MaximizeBox ? SystemInformation.CaptionButtonSize.Width : 0)
    // Close button (45 on Win8)
    - SystemInformation.CaptionButtonSize.Width;
}

You might try my little verification WinForm application

Source code: https://gist.github.com/CodeZombieCH/b9def0b0d9c41a98593a

Thanks to @Plutonix for the hint to SystemInformation.CaptionButtonSize.