从类文件访问表单控件

Question

我有一个mdi表单和许多子表单所有子表单都包含名为panel1的面板控件现在我想从我的类文件访问panel1控件，因为我写了下面的代码，但它不起作用。
Class1.cs文件：

public partial class FormBase : Form
{
    public FormBase()
    {
        this.Load += new System.EventHandler(this.FormLoad);
        //this.Resize += new System.EventHandler(this.FormResize);//error
        this.panel1.Resize += new System.EventHandler(this.FormResize);//error as a panel1 is not access
    }
    protected virtual void FormLoad(object sender, EventArgs e)
    {
        this.WindowState = FormWindowState.Maximized;
    }

    protected virtual void FormResize(object sender, EventArgs e)
    {
        //error : panel1 control has a red underline
        panel1.Left = (this.ClientSize.Width - panel1.Width) / 2;//error as a panel1 is not access
        panel1.Top = (this.ClientSize.Height - panel1.Height) / 2;//error as a panel1 is not access
    }
}

现在是我的一个孩子形式 frmAddNewEmployee.cs

public partial class frmAddNewEmployee : FormBase
{
    public frmAddNewEmployee()
    {   InitializeComponent();
    }

    protected override void FormLoad(object sender, EventArgs e)
    {
        base.FormLoad(sender, e);
    }

    protected override void FormResize(object sender, EventArgs e)
    {
        base.FormResize(((Panel)sender).Name, e);//error
        base.FormLoad(sender, e);//error
    }
}

所以我的问题是如何从我的Class1.cs文件

访问子窗体的这个panel1控件