Move PictureBox using Timer

Question

My goal is to move a picturebox back and forth. My issue is how to do this.

I have written the following:

    int x = enemy.Location.X;
    int y = enemy.Location.Y;
    enemy.Location = new Point(x+-1, y);

This moves the picturebox off-screen, left. After moving left, I'd like it to move right, so that it moves back and forth - in a continuous loop.

The noob that I am, I tried:

    if (x < 40)
        enemy.Location = new Point(x - -100, y);
    else if (x > 400)
        enemy.Location = new Point(x - 5, y);

This proves unsuccessful - the box doesn't seem to move on reaching pixel 40.

Is there a simple solution that you can prod me towards, or have I dug an early grave for myself?!

I should specify: I am writing in C# per college assignment requirements.

Cheers.

Answer 1

When moving left, when the x location reaches 0, change direction and move right.

When moving right, you need to use the width of the screen minus the width of your picturebox.

System.Windows.SystemParameters.PrimaryScreenWidth 

edit:

Or better yet, use the width of your form minus the width of the picturebox. Then it will still work if its not maximized.

Answer 2

Setup a variable that toggles between negative and positive values to make it go left and right. You toggle the direction by multiplying by -1. Then you simply add that variable to the current X value like this:

    private int direction = -1; // this can be values other than 1 to make it jump farther each move

    private void timer1_Tick(object sender, EventArgs e)
    {
        int x = enemy.Location.X + direction;
        if (x <= 0)
        {
            direction = -1 * direction;
            x = 0;
        }
        else if (x >= this.ClientRectangle.Width - enemy.Width)
        {
            direction = -1 * direction;
            x = this.ClientRectangle.Width - enemy.Width;
        }
        enemy.Location = new Point(x, enemy.Location.Y);
    }