How do I set a Windows Form to resize while maintaining the aspect ratio?

Question

C++ / C#

Adding a windows form element (not WPF).
It is necessary that the dimensions of the form do not lose the aspect ratio.
I use the "SizeChanged" form event, in it I build the resizing of the form, but for some reason it does not work correctly when the width changes, the height twitches from a larger value to the initial one, eventually retaining its initial value. And when you change the height, nothing happens.
There are given initial form size values ​​width = width_ = 600 and height = height_ = 450 and Height_K(width/height) and Width_K(height/width) transform coefficients are given.
Code:
private void Form_book_SizeChanged(object sender, EventArgs e)
{
if (Width != Width_)
{
Height = Height + (Width - Width_) * Height_K;
Width_ = Width;
}
else
{
Width = Width + (Height - Height_) * Width_K;
Height_ = Height;
}
}

Answer 1

You need to store the previous window sizes in private variables, and compare the new value with the previous one.
And if they have changed, then execute the resize code.