什么叫"未将对象引用设置到对象的实例"？ protected void Page_Load(object sender, EventArgs e)行 11:     {

    string scriptContent = Request.QueryString["user"].ToString() + "，欢迎您！请记住您的密        码：" + Request.QueryString["password"].ToString(); Response.Write(scriptContent);string scriptString = "aler('" + scriptContent + "');";  

源文件: e:ASP练习CH5_EX5-4_TextBox控件Content5-4.aspx.cs    行: 12