Question

我正在创建一个网络应用程序，在这个应用程序中，我想允许用户更新他们的用户信息（名字，姓氏，电子邮件，电话号码，公司名称）或更改他们的密码。页面加载时，它们的当前信息将输入到文本框中。我的问题是我不知道如何应用用户所做的更改。我的代码目前看起来像这样：

    DataClasses1DataContext context = new DataClasses1DataContext();
    User user = new User();


    protected void Page_Load(object sender, EventArgs e)
    {
        string usr = Session["SessionUserName"].ToString();

        user = (from u in context.Users
                    where u.username.Equals(usr)
                    select u).FirstOrDefault();

        txtFName.Text = user.firstName;
        txtLName.Text = user.lastName;
        txtCompany.Text = user.companyName;
        txtEmail.Text = user.email;
        txtPhone.Text = user.phoneNumber;


    }

    protected void btnUpdate_Click(object sender, EventArgs e)
    {

        using (DataClasses1DataContext context2 = new DataClasses1DataContext())
        {
            User nUser = (from u in context2.Users
                          where u.username == user.username
                          select u).SingleOrDefault();

            if (nUser != null)
            {
                //make the changes to the user
                nUser.firstName = txtFName.Text;
                nUser.lastName = txtLName.Text;
                nUser.email = txtEmail.Text;
                if (!String.IsNullOrEmpty(txtPhone.Text))
                    nUser.phoneNumber = txtPhone.Text;
                if (!String.IsNullOrEmpty(txtCompany.Text))
                    nUser.companyName = txtCompany.Text;
                nUser.timeStamp = DateTime.Now;
            }


            //submit the changes
            context2.SubmitChanges();

            Response.Redirect("Projects.aspx");

        }

这不会给我任何错误，但它也不会应用这些更改。一些谷歌搜索引导我添加

context2.Users.Attach(nUser);

但是这给了我错误消息：System.InvalidOperationException：无法附加已存在的实体。所以我试过

context2.Users.Attach(nUser, true);

我收到了同样的错误消息。

更多地看谷歌我发现了有关首先分离实体的信息，但该信息大约有3年的历史，并且似乎不再有效（因为context.Detach或context.Users.Detach不是选项并且给出如果我尝试使用它，我会构建错误）。我收到的其他错误消息（我不记得我是如何诚实地）建议我更改更新策略，因此我将Users类下的所有字段设置为永远不会更新策略。有人建议再次反序列化然后再序列化数据，但我找不到任何有关如何执行此操作的信息。任何帮助将不胜感激。

编辑：由于下面的一些建议而更改了代码，但它仍然无效。我没有收到任何错误消息，但数据没有被保存。

 protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            string usr = Session["SessionUserName"].ToString();

            user = (from u in context.Users
                    where u.username.Equals(usr)
                    select u).FirstOrDefault();

            txtFName.Text = user.firstName;
            txtLName.Text = user.lastName;
            txtCompany.Text = user.companyName;
            txtEmail.Text = user.email;
            txtPhone.Text = user.phoneNumber;
        }  

    }

    protected void btnUpdate_Click(object sender, EventArgs e)
    {



                //make the changes to the user
                user.firstName = txtFName.Text;
                user.lastName = txtLName.Text;
                user.email = txtEmail.Text;
                if (!String.IsNullOrEmpty(txtPhone.Text))
                    user.phoneNumber = txtPhone.Text;
                if (!String.IsNullOrEmpty(txtCompany.Text))
                    user.companyName = txtCompany.Text;
                user.timeStamp = DateTime.Now;
                //submit the changes
            context.SubmitChanges();

            Response.Redirect("Projects.aspx");

      }

Answer 1

这种情况正在发生，因为您在更新之前将相同的信息写回这些文本框。您需要做的就是将page_load更改为：

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        string usr = Session["SessionUserName"].ToString();

        user = (from u in context.Users
                where u.username.Equals(usr)
                select u).FirstOrDefault();

        txtFName.Text = user.firstName;
        txtLName.Text = user.lastName;
        txtCompany.Text = user.companyName;
        txtEmail.Text = user.email;
        txtPhone.Text = user.phoneNumber;
    }
}

在更新之前，page_load正在执行。因此，它重新分配原始值，然后使用相同的值更新它们。希望这可以帮助！祝你好运！

编辑：问题后的更改已更新：

将您的整个代码更改为此。我还添加了一些需要检查，你应该处理并从顶部删除全局变量：

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        if (Session["SessionUserName"] != null)
        {
            string usr = Session["SessionUserName"].ToString();

            DataClasses1DataContext context = new DataClasses1DataContext();
            User user = (from u in context.Users
                         where u.username.Equals(usr)
                         select u).FirstOrDefault();

            if (user != null)
            {
                txtFName.Text = user.firstName;
                txtLName.Text = user.lastName;
                txtCompany.Text = user.companyName;
                txtEmail.Text = user.email;
                txtPhone.Text = user.phoneNumber;
            }
            else
            {
                //--- handle user not found error
            }
        }
        else
        {
            //--- handle session is null
        }
    }
}

protected void btnUpdate_Click(object sender, EventArgs e)
{
    if (Session["SessionUserName"] != null)
    {
        string usr = Session["SessionUserName"].ToString();

        try
        {
            DataClasses1DataContext context = new DataClasses1DataContext();
            User nUser = (from u in context.Users
                          where u.username.Equals(usr)
                          select u).FirstOrDefault();

            //make the changes to the user
            nUser.firstName = txtFName.Text;
            nUser.lastName = txtLName.Text;
            nUser.email = txtEmail.Text;
            if (!String.IsNullOrEmpty(txtPhone.Text))
                nUser.phoneNumber = txtPhone.Text;
            if (!String.IsNullOrEmpty(txtCompany.Text))
                nUser.companyName = txtCompany.Text;
            nUser.timeStamp = DateTime.Now;

            //submit the changes
            context.SubmitChanges();

            Response.Redirect("Projects.aspx");
        }
        catch (Exception ex)
        {
            //--- handle update error
        }
    }
    else
    {
        //--- handle null session error
    }
}

这应该适合你。让我知道！祝你好运！

使用c＃asp.net更新Web应用程序中的用户信息

1 个答案: