c# - 无法删除用户外部登录

Question

我正在尝试使用个人帐户的 MVC 5.2 模板。一切正常，除了当我尝试删除用户登录时收到以下错误消息:

The operation failed: The relationship could not be changed because one or more of the foreign-key properties is non-nullable. When a change is made to a relationship, the related foreign-key property is set to a null value. If the foreign-key does not support null values, a new relationship must be defined, the foreign-key property must be assigned another non-null value, or the unrelated object must be deleted.

在 ManagerController 的下面一行:

var result = await this.UserManager.RemoveLoginAsync(this.User.Identity.GetUserId(), new UserLoginInfo(loginProvider, providerKey));

这是完整的 RemoveLogin 操作:

    [HttpPost]
    [Route("RemoveLogin")]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> RemoveLogin(string loginProvider, string providerKey)
    {
        ManageMessageId? message;
        var result = await this.UserManager.RemoveLoginAsync(this.User.Identity.GetUserId(), new UserLoginInfo(loginProvider, providerKey));
        if( result.Succeeded )
        {
            var user = await this.UserManager.FindByIdAsync(this.User.Identity.GetUserId());
            if( user != null )
                await this.SignInAsync(user, isPersistent: false);
            message = ManageMessageId.RemoveLoginSuccess;
        }
        else
            message = ManageMessageId.Error;

        return this.RedirectToAction("ManageLogins", new { Message = message });
    }

Answer 1

我能够通过更改行来让它工作:

public async Task<IActionResult> RemoveLogin(
    string loginProvider, 
    string providerKey)

到

public async Task<IActionResult> RemoveLogin(
    [Bind(Prefix = "Account.LoginProvider")]string loginProvider,
    [Bind(Prefix = "Account.ProviderKey")]string providerKey)

原因:

无论出于何种原因，MVC 绑定(bind)都没有正确解析参数绑定(bind):

<input asp-for="@account.LoginProvider" type="hidden" />
<input asp-for="@account.ProviderKey" type="hidden" />

正在创建以下表单:

<input type="hidden" id="account_LoginProvider" name="account.LoginProvider" value="Facebook">
<input type="hidden" id="account_ProviderKey" name="account.ProviderKey" value="...">

这些名称未绑定(bind)到参数名称 loginProvider 和 providerKey。

这是提供解决方法的答案:

https://stackoverflow.com/a/3869512/567524