How could I make textbox 1 change the font size of the text in textbox 2. similar to changing font size in google docs or Microsoft word

Question

So I have 2 text boxes, one of them for writing in and one of them for changing the font size, how could I make the font size text box make the font size in the writing text box change?

Answer 1

Well for starters, assuming it is a Windforms app with 2 textbox objects named `textBox1' and 'textBox2' respectively, it isn't so difficult to rig up a quick way to to this.

First, in your forms load event you need to set the initial value of textBox2

        private void Form1_Load(object sender, EventArgs e)
        {
            textBox2.Text = textBox1.Font.Size.ToString();

        }

then, from there you just need to create a TextChanged event for textBox2 either by double clicking the textBox2 object(in visual editor) or selecting the event from the events creator.

Finally, to handle the event in a quick and easily broke down fashion for beginners:

        private void textBox2_TextChanged(object sender, EventArgs e)
        { 
            //use try/catch incase user inputs invalid value and cannot parse it as a float
            try
            {
                //Cannot set the Size value of a font, so create a new font with desired size, referencing currrent textBox1.Font properties,
                textBox1.Font = new Font(textBox1.Font.FontFamily.ToString(), float.Parse(textBox2.Text), textBox1.Font.Style, textBox1.Font.Unit, textBox1.Font.GdiCharSet, textBox1.Font.GdiVerticalFont);
                //It worked, textBox2 background color stays white to signify success.
                textBox2.BackColor = Color.White;
            }
            catch (Exception)
            {
                //An exception was thrown parsing input, set textBox2 background to red so user knows this is invalid.
                textBox2.BackColor = Color.Red;      
            }
        }