菜鸟一个，求指导！！！关于FileUpload

Question

在click事件外定义了alreadyup默认值是false，Compfilename（）函数是判断是否有同名文件，
代码运行有两个地方不对
1、文件大小判断那里，不大于的执行没有问题，大于以后Lable1。text没有给赋值
2、上传成功后再次点上传按钮还能上传。already的值似乎没有变啊
protected void Button1_Click(object sender, EventArgs e)
    {
        if(alreadyup == false)
        {
            string savepath = Request.PhysicalApplicationPath + @"\upfiles\";
            if (FileUpload1.HasFile)
            {
                int filelength = FileUpload1.PostedFile.ContentLength;
                fileNames = FileUpload1.FileName;
                if(Compfilename(savepath,fileNames))
                {
                    Label1.Text = "文件名已存在，请重命名后上传，谢谢！";
                }
                else
                {
                    if(filelength > 5242880)
                    {
                        Label1.Text = "文件太大，上传文件必须小于5M";
                    }
                    else
                    {
                        savepath += fileNames;
                        FileUpload1.SaveAs(savepath);
                        alreadyup = true;
                        Label1.Text = "上传成功！";
                        havefile = "1";
                    }
                }
            }
            else
            {
                Label1.Text = "上传失败！";
            }
        }
        else
        {
            Label1.Text ="已经上传了文件";
        }
    }

Answer 1

调试， alreadyup 是不是被重置了