.NET 6 会话上的 Blazor 服务器应用程序中类型的错误转换对象

Question

我正在使用 Entity Framework Core 验证数据库中的用户和密码，但是当我尝试使用多态性声明

var authenticationExt

时，因为该类继承自

authenticationProvider

，调试器会显示：

System.InvalidCastException：无法将类型“Microsoft.AspNetCore.Components.Server.ServerAuthenticationStateProvider”的对象转换为类型“Blazor_Server_App_Login.Extensions.AuthenticationExt”

我从 .NET 7 中的项目中提取了相同的代码。有什么建议吗？

@page "/"
@layout LoginLayout

@inject HttpClient httpClient
@using Blazor_Server_App_Login.Extensions
@using Blazor_Server_App_Login.Shared
@using Blazor_Server_App_Login.Login
@using Microsoft.AspNetCore.Components.Authorization
@inject AuthenticationStateProvider authenticationProvider
@inject NavigationManager navManager

<div class="row mt-5">
    <div class="col-lg-4 offset-lg-4 border">
        <div class="mb-3 text-center">
            <h3>LOGIN</h3>
        </div>
        <div class="mb-3">
            <label>Email</label>
            <input @bind="login.email" class="form-control" />
        </div>
        <div class="mb-3">
            <label>Password</label>
            <input @bind="login.password" class="form-control" />
        </div>
        <div class="mb-3">
            <button @onclick="IniciarSesion" class="btn btn-primary">Login</button>
        </div>

    </div>

</div>

@code {
    private UserLogin login = new UserLogin();
    private async Task IniciarSesion()
    {
        var loginResponse = await httpClient.PostAsJsonAsync<UserLogin>("https://localhost:7146/api/User/Login", login);
        if (loginResponse.IsSuccessStatusCode)
        {
            // AuthenticationStateProvider i = new AuthenticationExt();
            var sesionUser = await loginResponse.Content.ReadFromJsonAsync<SessionState>();
            var autenticationExt = (AuthenticationExt)authenticationProvider;
            await autenticationExt.UdateAuthState(sesionUser);
            navManager.NavigateTo("/Index");
        }
    }
}

完整代码位于：https://github.com/bonfildev/Blazor-Server-App-Login

Answer 1

我在github上检查了你的代码

按照此文档修改服务顺序：

    builder.Services.AddServerSideBlazor();
    //make sure your AuthenticationStateProvider is registered after basic blazor services registered by `AddServerSideBlazor` method
    builder.Services.AddScoped<AuthenticationStateProvider, AuthenticationExt>();
    //remove the codes below
    //builder.Services.AddScoped<AuthenticationExt>();

自从您在 AuthenticationStateProvider 中注入 ISessionStorage

修改

<component type="typeof(App)" render-mode="ServerPrerendered" />

到

<component type="typeof(App)" render-mode="Server" />

这样您就可以避免 JavaScript 互操作异常，文档相关