Windows Store Apps: measure many pixels a TextBlock width will be?

Question

Is there a way to measure many pixels will a TextBlock width will occupy? let's say I have a string with length of 10 characters.

and I have a text block (without an assigned width value), I'll set the string to the Text property of that textblock.

Is there a way to measure the actual width of the textblock before adding it to the layout?

Answer 1

Well, the only way I got is to create a new -in memory- text block- then assign it the same text, style and attributes as my target TextBlock, I assumed that my text block has a fixed height, to calculate it's desired width to fit the text, I made the following function:

private double CalculateDesiredWidth(string text, TextBlock targetText)
        {
            int MIN_TEXT_WIDTH=200;
            //create a new text block to calculate how much space will the string occupy
            TextBlock txt = new TextBlock();
            txt.Text = text;
            txt.FontSize = 16;
            txt.Margin = targetText.Margin;
            Size desiredSize = new Size(0, targetText.ActualHeight);
            Rect desiredRect = new Rect(new Point(0, 0), desiredSize);

            //measure the desired size
            txt.Measure(desiredSize);
            txt.Arrange(desiredRect);
            //if the desired width is small, use the minimum default width
            if (txt.ActualWidth <= MIN_TEXT_WIDTH)
                return MIN_TEXT_WIDTH;
            //calculate the desired area
            double desiredArea = txt.ActualWidth * txt.ActualHeight;
            //calculate the the width required to fit the desired area to my text box
            double width = desiredArea / (targetText.Height - txt.Margin.Top - txt.Margin.Bottom);
            return width;
        }