nastajus / cs-net-WpfApp-resizable

https://www.youtube.com/watch?v=J4J3ZcXRN_E Windows Forms tutorial - C#

Purpose: resize all widget elements on the form, by simply listening for mouse event and keyboard events. Like how i expect all forms in all applications to always work. Default font of 8 pt is too squinty by far for my tastes.

Topics

• Visual Studio windows hiding locations.
• Delegates
• KeyEventHandler delegate
• MouseWheel delegate.
• Capture keyboard and mouse.

Gotchas

• WPF replaced WinForms.

• Diagnostic Window - not visible.

  • Checked a few menus to activate it:
  1. View > Other Windows > nope.
  2. Debug > Windows > nope. (while form not running)
  3. Debug > Windows > still nope. (while form running -- much more choices, but still nope.)
  • resolution: TBD. (also, doesn't matter.)

• attempted combination MS Guide example of Delegates with this code snippet resulted in the error message: System.ArgumentException: 'Handler type is mismatched.'

  • reason being that the MS Guide was showcasing the entire delegate concept, which involves a pair of functions. I was not appropriately combining in my first attempt, which fueled all the lessons.

  • what I needed to do was discover the first method of delegate type KeyEventArgs existed, which I had not seen yet from these two disparate examples I had quickly assembled.

  • and second, I needed to realize I was supposed to implement my own method of matching signature to the first method. i may refer to this as "overriding method" or "extending method".

  • the guide refers to wrapping when bridging these two levels.

• mousewheel delegates work differently, seemingly.

• using static System.Windows.UIElement; -- not sure why wasn't necessary for MouseWheel += MouseWheelDelegate; to work, somehow the scope of this class "knew" this.

Observations

• Delegates
  1. The invocation of System.Windows.RegisterClassHandler(...) accepts a type of Delegate as the third parameter.
  2. That third paramater example takes an input of type new KeyEventHandler(keyUp) and invokes a developer-custom method signature of keyUp(object sender, KeyEventArgs e), to compile & execute successfully.
  3. Changing either paramater of the dev. meth. breaks typing, preventing compilation and thus execution obviously.
  4. Navigating to definition (F12) shows that matching signature, appearing that delegates are designed to overriden.

namespace System.Windows.Input
{
    public delegate void KeyEventHandler(object sender, KeyEventArgs e);
}

- summary: One essentially passes in a method of matching signature, which will be eventually called. Precisely how TBD.