Question

Please consider that im a newcomer to c#. After scanning about 700 posts i decided to post one more question:

On my windows form (c#) I have some controls including textboxes, checkboxes and so on.
I want to change the backcolor whenever the controls become active.
I know i could raise ‘enter’ and ‘leave’ events for each control to change the corresponding properties but there should be another way.

Answer 1

Simply hook Enter and Leave events – toggling the color in each. Save the last color saved in OnEnter to use in OnLeave

public Form1()
{
    InitializeComponent();

    var lastColorSaved = Color.Empty;

    foreach(Control child in this.Controls)
    {
        child.Enter += (s, e) =>
                            {
                                var control = (Control)s;
                                lastColorSaved = control.BackColor;
                                control.BackColor = Color.Red;
                            };
        child.Leave += (s, e) =>
                            {
                                ((Control)s).BackColor = lastColorSaved;
                            };
    }
}