char SideA = 'A';
char SideB = 'B';
int CPUPlayer = 1;
Test.Text = x.ToString();

if (difficulty == 1)
{ 
    if (CPUPlayer == 1)
    {

        string targetString = "";
        for (int side = 1; side <= 1; side++)
        {

            targetString = SideA.ToString();
            Test.Text = targetString.ToString();
            for (int game = 1; game < 25; game++)
            {
                targetString = game.ToString();
                for (int tile = 1; tile < 10; tile++)
                {
                    targetString = tile.ToString();
                    PictureBox target = (PictureBox)(this.Controls.Find(targetString,true))[0];
                    if (target.BackgroundImage == null)
                    {
                        target.BackgroundImage = Properties.Resources.smallo;
                        Test.Text = targetString.ToString();
                    }
                }
            }

        }
    }
}

因此，我尝试通过命名的PictureBox（例如A11，A12，A13等）进行循环，以使它们通过使用循环字符串连接到图片框来更改背景图片，但我一直在{{ 1}}来自Index is out of range

我不确定该如何解决。我对C＃和编码通常还是很陌生，所以很高兴知道我缺少什么！