如何在实例化新表单时不丢失参数

我的代码是这样的:

    private void button3_Click(object sender, EventArgs e)
    {
        schema s1 = new schema(readedImage);
        s1.ShowDialog();
        if(s1.imgToReturn != null)
        {
            readedImage = s1.imgToReturn;
            s1.imgToReturn = null;
        }
        s1.Dispose();
    }

因为我正在创建一个新的实例，我没有得到"readdimage"在新的形式时调用。showdialog()稍后。有没有办法在。showdialog动作中给出参数?

编辑:这是模式表单的构造函数:

    public schema(Image readedImage = null)
    {
        InitializeComponent();
        imgToReturn = readedImage;
    }

您好，感谢您的帮助

private void button3_Click(object sender, EventArgs e)
{
    schema s1 = new schema(readedImage);
    if(s1.ShowDialog() == DialogResult.OK)
    {
        if(s1.imgToReturn != null)
        {
            readedImage = s1.imgToReturn;
            s1.imgToReturn = null;
        }
        s1.Dispose();
    }
}