1、通过自定义方法配置

1）在Startup中ConfigureServices方法中配置自定义方法SetupIdentityServer

services.AddIdentityServer(*SetupIdentityServer*)
        .AddSigningCredential(...)
        .AddValidationKeys()
        .AddConfigurationStore(builder => builder.UseSqlServer(""))
        .AddOperationalStore(builder => builder.UseSqlServer(""))
        .AddAspNetIdentity<ApplicationUser>();

2）上面配置的SetupIdentityServer方法中配置登陆地址

private static void SetupIdentityServer(IdentityServerOptions identityServerOptions)
{
    identityServerOptions.UserInteraction.LoginUrl = "/Controller/Action";
}

2、直接在Startup中ConfigureServices中配置

services.AddIdentityServer(options =>
            {
                options.UserInteraction = new IdentityServer4.Configuration.UserInteractionOptions
                {
                    LoginUrl = "/Account/Login",//登录地址  
                    LogoutUrl = "/Account/Logout",//退出地址 
                    ConsentUrl = "/Account/Consent",//允许授权同意页面地址
                    ErrorUrl = "/Account/Error", //错误页面地址
                    LoginReturnUrlParameter = "ReturnUrl",//设置传递给登录页面的返回URL参数的名称。默认为returnUrl 
                    LogoutIdParameter = "logoutId", //设置传递给注销页面的注销消息ID参数的名称。缺省为logoutId 
                    ConsentReturnUrlParameter = "ReturnUrl", //设置传递给同意页面的返回URL参数的名称。默认为returnUrl
                    ErrorIdParameter = "errorId", //设置传递给错误页面的错误消息ID参数的名称。缺省为errorId
                    CustomRedirectReturnUrlParameter = "ReturnUrl", //设置从授权端点传递给自定义重定向的返回URL参数的名称。默认为returnUrl                   
                    CookieMessageThreshold = 5 //由于浏览器对Cookie的大小有限制，设置Cookies数量的限制，有效的保证了浏览器打开多个选项卡，一旦超出了Cookies限制就会清除以前的Cookies值
                };

            })
                .AddDeveloperSigningCredential()
                .AddInMemoryIdentityResources(MemoryClients.GetIdentityResources())
                .AddInMemoryApiResources(MemoryClients.GetApiResources())
                .AddInMemoryClients(MemoryClients.GetClients());