Help with homing missile I have one part working

[Onion13]

Making a scrolling space shooting video game in C# where the player will fight one on one with their opponent. I was able to figure out how to make the missile go up if the opponent was above the player. But, I can't seem to make it work if the opponent is below or right infront of the player. Can someone help me? I know the answer is right under my nose.

The function below handles the movement of the missile

 void movemissile()
        {
            foreach (Control y in this.Controls)
            {
                if (y is PictureBox && y.Tag == "missile") 
                {

                    //y.Left += 100;//x.Top -= 10;
                    if (y.Left > enemy.Left)//<100
                    {
                        y.Left += 10;
                        //this.Controls.Remove(y);
                    }

                    //plyer missile goes up if opponent is above
                    if (y.Top > enemy.Top)
                    {
                        y.Left += 10;
                        y.Top -= 20;
                        y.Left += 10;
                        //this.Controls.Remove(y);
                    }
                    y.Left += 100;//x.Top -= 10;
                    if (y.Top > enemy.Left)//<100
                    { 
                        this.Controls.Remove(y);
                    }
                }
            }
        }

        This function handles drawing the missile of the player for the game.
                void Missile()
        {
            PictureBox m = new PictureBox();
            m.SizeMode = PictureBoxSizeMode.AutoSize;
            m.Image = Properties.Resources.Missile1;
            m.BackColor = System.Drawing.Color.Transparent;
            m.Tag = "missile";
            m.Left = Player.Left + 100;//moves bullet left or right
            m.Top = Player.Top + 55;//55 is perfect
            this.Controls.Add(m);
            m.BringToFront();
        }

[Schol-R-LEA]

While I have some other thoughts about how to improve this code, my immediate thought regarding the left/right and up/down movements of the missile is something like so:

                if (y.Left > enemy.Left)
                {
                     y.Left += 10;
                }
                else if (y.Left < enemy.Left)
                {
                     y.Left -= 10;
                }
                else 
                {
                    // no change, stay on course
                }

                if (y.Top < enemy.Top)
                {
                     y.Top += 10;
                }
                else if (y.Top > enemy.Top)
                {
                     y.Top -= 10;
                }
                else 
                {
                    // no change, stay on course
                }
                if ((abs(y.Left - enemy.left) < 5) && (abs(y.Top - enemy.Top) < 5))
                {
                    // impact
                }

I suspect you've tried this already, however.

[tinstaafl]

The first thing I'd suggest is, use m.Name = "missile", instead of Tag. This allows you to get rid of that loop and access the missile picturebox directly using indexing, PictureBox y = (PictureBox)this.Controls["missile"];

Instead of trying to calculate the trajectory of the missile, you can use the Location property of the player and the enemy to calculate the direction of the missile movement and have it step a portion of the path each time you call MoveMissile. Something like this should work:

    int missileStep { get; } = 10;
    void MoveMissile()
    {
        PictureBox missile = (PictureBox)Controls["missile"];
        int xOffset = (enemy.Location.X - player.Location.X) / missileStep;
        int yOffset = (enemy.Location.Y - player.Location.Y) / missileStep;
        missile.Location = new Point(missile.Location.X + xOffset, missile.Location.Y + yOffset);
        if (missile.Location == enemy.Location)
        {
            Controls.Remove(missile);
        }
    }

missileStep can set to the value which suits you best.