就是显示无法绑定句柄 要有什么办法才能成功的 啊？？

static void Main()
{
Application.Run(new Form1());
}

private void Form1_Load(object sender, System.EventArgs e)
{
textBox1.Text = "";
}

private void button1_Click(object sender, System.EventArgs e)
{
DirectoryInfo d = new DirectoryInfo("C:\\");
DirectoryInfo[] sud = d.GetDirectories();
for (Directory dd in sud)
{
if (dd.Attibutes == FileAttributes.Directory)
{
FileInfo[] f = dd.GetFiles();
foreach (FileInfo fi in f)
{
MessageBox.Show(fi.ToString());

不调试直接运行

提示的错误在哪个语句?