Ну, picture
является локальной переменной и, таким образом, не виден снаружи Button1_Click
. Давайте превратим его в поле :
// now picture is a private field, visible within th class
//TODO: do not forget to Dispose it
private PictureBox picture;
private void Button1_Click(object sender, EventArgs e)
{
if (picture != null) // already created
return;
picture = new PictureBox
{
Name = "pictureBox",
Size = new Size(20, 20),
Location = new System.Drawing.Point(x, y),
Image = image1,
Parent = this, // instead of this.Controls.Add(picture);
};
timer1.Enabled = true;
}
private void Timer1_Tick(object sender, EventArgs e)
{
//redefine pictureBox position.
x = x - 50;
if (picture != null) // if created, move it
picture.Location = new System.Drawing.Point(x, y);
}