c# – System.Array’不包含’Count’的定义

protected void Page_Prerender(object sender,EventArgs e)
{
    FileInfo[] fileInfo;
    string UpFolder = Server.MapPath("~/data/images/");
    DirectoryInfo dir = new DirectoryInfo(UpFolder);
    fileInfo = dir.GetFiles();
    // here i am getting error
    int TotalImages = fileInfo.Count();
    for (int count = 0; count < TotalImages; count++)
    {
        Image image = new Image();
        image.ImageUrl = "~/data/images/" + fileInfo[count].ToString();
        image.ID = count.ToString();
        DataListImage.Controls.Add(image);
    }
    DataListImage.DataSource = dir.GetFiles();
    DataListImage.DataBind();

    string UpFolder1 = Server.MapPath("~/data/thumbnails/");
    DirectoryInfo dir1 = new DirectoryInfo(UpFolder1);
    DataListthumbnails.DataSource = dir1.GetFiles();
    DataListthumbnails.DataBind();
}