Nop源码分析 九--LocalizationService获取资源继续研究

通过如下方法获取资源：

public virtual string GetResource(string resourceKey)
        {
            if (_workContext.WorkingLanguage != null)
                return GetResource(resourceKey, _workContext.WorkingLanguage.Id);
            
            return "";
        }

而_workContext.WorkingLanguage就是返回是Language实体对象， 传入资源KEY和语言ID ，最终调用如下：

/// <summary>
        /// Gets a resource string based on the specified ResourceKey property.
        /// </summary>
        /// <param name="resourceKey">A string representing a ResourceKey.</param>
        /// <param name="languageId">Language identifier</param>
        /// <param name="logIfNotFound">A value indicating whether to log error if locale string resource is not found</param>
        /// <param name="defaultValue">Default value</param>
        /// <param name="returnEmptyIfNotFound">A value indicating whether an empty string will be returned if a resource is not found and default value is set to empty string</param>
        /// <returns>A string representing the requested resource string.</returns>
        public virtual string GetResource(string resourceKey, int languageId,
            bool logIfNotFound = true, string defaultValue = "", bool returnEmptyIfNotFound = false)
        {
            string result = string.Empty;
            if (resourceKey == null)
                resourceKey = string.Empty;
            resourceKey = resourceKey.Trim().ToLowerInvariant();
            if (_localizationSettings.LoadAllLocaleRecordsOnStartup)
            {
                //load all records (we know they are cached)
                var resources = GetAllResourceValues(languageId);
                if (resources.ContainsKey(resourceKey))
                {
                    result = resources[resourceKey].Value;
                }
            }
            else
            {
                //gradual loading
                string key = string.Format(LOCALSTRINGRESOURCES_BY_RESOURCENAME_KEY, languageId, resourceKey);
                string lsr = _cacheManager.Get(key, () =>
                {
                    var query = from l in _lsrRepository.Table
                                where l.ResourceName == resourceKey
                                && l.LanguageId == languageId
                                select l.ResourceValue;
                    return query.FirstOrDefault();
                });

                if (lsr != null) 
                    result = lsr;
            }
            if (String.IsNullOrEmpty(result))
            {
                if (logIfNotFound)
                    _logger.Warning(string.Format("Resource string ({0}) is not found. Language ID = {1}", resourceKey, languageId));
                
                if (!String.IsNullOrEmpty(defaultValue))
                {
                    result = defaultValue;
                }
                else
                {
                    if (!returnEmptyIfNotFound)
                        result = resourceKey;
                }
            }
            return result;
        }

_localizationSettings.LoadAllLocaleRecordsOnStartup 这一句 是ISetting的子类，所以配置都在Setting表里 返回是true.

var resources = GetAllResourceValues(languageId); 根据语言ID，获得所有资源：

/// <summary>
        /// Gets all locale string resources by language identifier
        /// </summary>
        /// <param name="languageId">Language identifier</param>
        /// <returns>Locale string resources</returns>
        public virtual Dictionary<string, KeyValuePair<int,string>> GetAllResourceValues(int languageId)
        {
            string key = string.Format(LOCALSTRINGRESOURCES_ALL_KEY, languageId);
            return _cacheManager.Get(key, () =>
            {
                //we use no tracking here for performance optimization
                //anyway records are loaded only for read-only operations
                var query = from l in _lsrRepository.TableNoTracking
                            orderby l.ResourceName
                            where l.LanguageId == languageId
                            select l;
                var locales = query.ToList();
                //format: <name, <id, value>>
                var dictionary = new Dictionary<string, KeyValuePair<int, string>>();
                foreach (var locale in locales)
                {
                    var resourceName = locale.ResourceName.ToLowerInvariant();
                    if (!dictionary.ContainsKey(resourceName))
                        dictionary.Add(resourceName, new KeyValuePair<int, string>(locale.Id, locale.ResourceValue));
                }
                return dictionary;
            });
        }

我们看到private readonly IRepository<LocaleStringResource> _lsrRepository;

原来所有的语言资源都存在LocaleStringResource表里。  查出后放到字典类型里返回，当然是要缓存的。最后取出值返回。OVER.