Hello, HashCode, how to make it so that while the cursor is on the form, then the parameter

this.Opacity = 100;

As soon as the cursor leaves the form, the parameter changes to

 this.Opacity = 30;
  • one
    Look at the events Leave, MouseLeave or LostFocus for the form, unfortunately, there is no way to check for yourself. - Specter

2 answers 2

For C # WinForms, MouseEnter and MouseLeave events:

 private void Form1_MouseEnter(object sender, EventArgs e) { this.Opacity = 1; } private void Form1_MouseLeave(object sender, EventArgs e) { this.Opacity = 0.3; }

    What was offered to you with MouseEnter / MouseLeave is a bad decision. If you have controls on the form, then in the case of this decision, this situation may arise:

     +---------------------------------+ | [Inner Control] | +---------------------------------+ Parent.OnMouseEnter (1.0) Parent.OnMouseLeave (0.3) Inner.OnMouseEnter (1.0) Inner.OnMouseLeave (0.3) Parent.OnMouseEnter (1.0) Parent.OnMouseLeave (0.3)

    A good solution involves inserting a dummy panel (and checking for MouseEnter / MouseLeave its boundaries) or MouseEnter / MouseLeave with message filtering.