Restricting user to upload a file of specific size

  public int maxSize { get; set; }

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            maxSize = 1048576;
        }

    }

 protected void lnkAttach_Click(object sender, EventArgs e)
    {
        if (FileUpload1.PostedFile.ContentLength < maxSize)
            {
              //Implementation
            }

       else
           {
                 lblrMessage.Text = "File Size ShouldNot Exceed More than 1 MB";
           }
    }