How to create fade in/out effect on mouse hover over window in C# VS2010?

Question

I have a login form (Form1) that I want to be faded out untill the user moves over it with the mouse, and when the user leaves the window, it goes back to the initial transparency.

I have tried MouseHover and MouseLeave events but cannot achieve the desired effect, could someone please help me?

Answer 1

public partial class Form1 : Form
{
    private Panel panel1;
    private PictureBox pictureBox1;
    private Timer timer;
    private double opacity_increment;
    private bool mouse_over;
    public Form1()
    {
        InitializeComponent();
        opacity_increment = 0.1d;
        timer = new Timer();
        timer.Interval = 100;
        timer.Tick += new EventHandler(timer_Tick);
        timer.Enabled = true;

        panel1 = new Panel();
        pictureBox1 = new PictureBox();

        ((System.ComponentModel.ISupportInitialize)(pictureBox1)).BeginInit();
        SuspendLayout();

        panel1.Dock = System.Windows.Forms.DockStyle.Fill;
        panel1.Location = new System.Drawing.Point(0, 0);
        panel1.Name = "panel1";
        panel1.BackColor = Color.Black;
        panel1.Size = new System.Drawing.Size(322, 180);
        panel1.TabIndex = 0;
        panel1.MouseEnter += new EventHandler(MouseEnterLogic);
        panel1.MouseLeave += new EventHandler(MouseLeaveLogic);

        pictureBox1.BackColor = System.Drawing.Color.Maroon;
        pictureBox1.Location = new System.Drawing.Point(0, 0);
        pictureBox1.Name = "pictureBox1";
        pictureBox1.Size = new System.Drawing.Size(100, 50);
        pictureBox1.TabIndex = 0;
        pictureBox1.TabStop = false;
        pictureBox1.MouseEnter += new EventHandler(MouseEnterLogic);
        pictureBox1.MouseLeave += new EventHandler(MouseLeaveLogic);

        Controls.Add(panel1);
        panel1.Controls.Add(pictureBox1);

        ((System.ComponentModel.ISupportInitialize)(pictureBox1)).EndInit();
        ResumeLayout();
    }
    private void timer_Tick(object sender, EventArgs e)
    {
        if (mouse_over)
        {
            if (Opacity <= 1)
            {
                Opacity += opacity_increment;
            }
        }
        else
        {
            if (Opacity >= 0.5d)
            {
                Opacity -= opacity_increment;
            }
        }
    }
    private void MouseLeaveLogic(object sender, EventArgs e)
    {
        if (Cursor.Position.X > this.Location.X + this.Width - 10 || Cursor.Position.Y > this.Location.Y + this.Height - 10 || Cursor.Position.X < this.Location.X + 10 || Cursor.Position.Y < this.Location.Y + 30)
            mouse_over = false;
    }
    private void MouseEnterLogic(object sender, EventArgs e)
    {
        mouse_over = true;
    }
    // You don't need overrides because if you have docked panel on the form thus the cursor will never firing these methods (cursor never overlaps the form).
    //protected override void OnMouseEnter(EventArgs e)
    //{
    //    MouseEnterLogic(this, e);
    //    base.OnMouseEnter(e);
    //}
    //protected override void OnMouseLeave(EventArgs e)
    //{
    //    MouseLeaveLogic(this, e);
    //    base.OnMouseEnter(e);
    //}
}