从寄存器控制器转移价值

Question

我在将值从方法 "OnPostAsync" 转移到 Register.cshtml 时遇到问题。 ViewBag 不起作用。如何解决这个问题。

public async Task<IActionResult> OnPostAsync(string returnUrl = null)
{
    returnUrl = returnUrl ?? Url.Content("~/");
    if (ModelState.IsValid)
    {
        var db = new ApplicationDbContext(_optionsBuilder.Options);
        var email = db.Users.Where(s => s.Email == Input.Email);
        if (email.Count() != 0)
        {
            ViewBag.pom = 100; // this doesn't work
            ViewData["duplicateEmail"] = "Email is already taken";
            return Page();
        }

...

@{
    ViewData["Title"] = "Register";
}

<h2>@ViewData["Title"]</h2>

<div class="row">
    <div class="col-md-4">
        <form asp-route-returnUrl="@Model.ReturnUrl" method="post">
            <h4>Create a new account.</h4>
            <h4>@ViewData["duplicateEmail"] error: @ViewBag.pom</h4>
            <hr />
...

Answer 1

根据 docs:

ViewBag isn't available in Razor Pages.

有关 为什么 不是开箱即用的更多信息，请参阅此 GitHub issue，其中包括 Damien Edwards 本人的一些评论：

We purposefully didn't add ViewBag because I wanted to discourage its use.

...

ViewBag uses dynamic which in our testing introduces a measurable performance impact on the processing of pages or views that use it. As such, I'd rather it not be available by default.

解决方案是要么使用明确的属性（就像您对 ReturnUrl 所做的那样），要么只使用 ViewData（就像您对 duplicateEmail).

Answer 2

尝试用 viewData 替换 viewBag：

ViewData["pom"] = 100; 
ViewData["duplicateEmail"] = "Email is already taken";
return Page();

<div class="row">
    <div class="col-md-4">
        <form asp-route-returnUrl="@Model.ReturnUrl" method="post">
            <h4>Create a new account.</h4>
            <h4>@ViewData["duplicateEmail"] error: @ViewData["pom"]</h4>
            <hr />

ViewBag 被故意遗漏在 razor 页面中。

从寄存器控制器转移价值

Transfer of value from register controller

c#

asp.net-core

asp.net-core-identity