Asp.net core .Resx文件在.cs文件中使用时为空

我正在尝试从.resx文件读取数据。它在视图中运行良好，但在.cs中使用时遇到问题

我收到以下运行时错误：

对象引用未设置为对象的实例

MailComposer.cs

    IStringLocalizer<SharedResources> SharedLocalizer;


public void SendActivityCreated (Activity entity) {
            var path = Path.Combine (environment.ContentRootPath, "wwwroot", "mail_templates", "activity_created", "index.html");
            var template = File.ReadAllText (path);
            template = template.Replace ("##ID##", entity.ID.ToString ());
            var x = SharedLocalizer["NewActivity"]; // Getting "Object reference not set to an instance of an object" here
            var title = $"Platform.Ge - {x} #{entity.ID}";
            var responsibleEmail = template.Replace ("##USER##", entity.Responsible.Name);
            emailSender.SendEmailAsync (entity.Responsible.Email, title, responsibleEmail);

        }

IStringLocalizer共享定位器；
已创建公共无效SendActivityCreated（活动实体）{
var path=path.Combine（environment.ContentRootPath、“wwwroot”、“邮件模板”、“创建的活动”、“index.html”）；
var template=File.ReadAllText（路径）；
template=template.Replace（“##ID###”，entity.ID.ToString（））；
var x=SharedLocalizer[“NewActivity”]；//在此处获取“对象引用未设置为对象的实例”
var title=$“Platform.Ge-{x}{entity.ID}”；
var responsibleEmail=template.Replace（“##用户###”，entity.Responsible.Name）；
emailSender.SendEmailAsync（entity.Responsible.Email，title，responsibleEmail）；
}

Startup.cs

services.Configure<RequestLocalizationOptions> (opts => {
    var supportedCultures = new [] {
    new CultureInfo ("en"),
    new CultureInfo ("ka"),
    new CultureInfo ("ru")
    };

    opts.DefaultRequestCulture = new RequestCulture ("ka");
    // Formatting numbers, dates, etc.
    opts.SupportedCultures = supportedCultures;
    // UI strings that we have localized.
    opts.SupportedUICultures = supportedCultures;
  });

services.Configure（选项=>{
var supportedCultures=new[]{
新文化信息（“en”），
新文化信息（“ka”），
新文化信息（“ru”）
};
opts.DefaultRequestCulture=新的RequestCulture（“ka”）；
//格式化数字、日期等。
opts.SupportedCultures=SupportedCultures；
//我们已经本地化的UI字符串。
opts.supporteduccultures=支持的文化；
});

我有SharedResources.ka.resx和SharedResources.en.resx文件。如何从MailComposer.cs的SharedLocalizer实例中的这两个文件中获取数据？

解决方案1：

在

MailComposer.cs

中注入

SharedResources

：

IStringLocalizer<SharedResource> SharedLocalizer;

public MailComposer(IStringLocalizer<SharedResource> _SharedLocalizer)
{
    SharedLocalizer = _SharedLocalizer;
}

services.AddScoped<MailComposer>();

IStringLocalizer<SharedResource> SharedLocalizer;

public MailComposer(IStringLocalizer<SharedResource> _SharedLocalizer)
{
    SharedLocalizer = _SharedLocalizer;
}

将

MailComposer

插入要调用

SendActivityCreated

函数的位置：

private readonly MailComposer _mailComposer;
public  HomeController(MailComposer mailComposer){

    _mailComposer = mailComposer;
}

private readonly IStringLocalizer<SharedResource> _localizer;
public  HomeController(IStringLocalizer<SharedResource> localizer){

    _localizer = localizer;
}

并使用类似于：

_mailComposer.SendActivityCreated(entity);

MailComposer a = new MailComposer(_localizer);
a.SendActivityCreated(entity);

解决方案2：

在

MailComposer.cs

中注入

SharedResources

：

IStringLocalizer<SharedResource> SharedLocalizer;

public MailComposer(IStringLocalizer<SharedResource> _SharedLocalizer)
{
    SharedLocalizer = _SharedLocalizer;
}

services.AddScoped<MailComposer>();

IStringLocalizer<SharedResource> SharedLocalizer;

public MailComposer(IStringLocalizer<SharedResource> _SharedLocalizer)
{
    SharedLocalizer = _SharedLocalizer;
}

并使用类似于：

_mailComposer.SendActivityCreated(entity);

MailComposer a = new MailComposer(_localizer);
a.SendActivityCreated(entity);