我正在使用NDepend，在下面的代码中，它检测到这种代码气味。
但是如果我添加只读，那么它将无法编译。
namespace todo
{
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Linq.Expressions;
using System.Threading.Tasks;
using Microsoft.Azure.Documents;
using Microsoft.Azure.Documents.Client;
using Microsoft.Azure.Documents.Linq;
public static class DocumentDBRepository<T> where T : class
{
private static readonly string DatabaseId = ConfigurationManager.AppSettings["database"];
private static readonly string CollectionId = ConfigurationManager.AppSettings["collection"];
private static DocumentClient client;
public static async Task<T> GetItemAsync(string id)
{
try
{
Document document = await client.ReadDocumentAsync(UriFactory.CreateDocumentUri(DatabaseId, CollectionId, id));
return (T)(dynamic)document;
}
catch (DocumentClientException e)
{
if (e.StatusCode == System.Net.HttpStatusCode.NotFound)
{
return null;
}
else
{
throw;
}
}
}
public static async Task<IEnumerable<T>> GetItemsAsync(Expression<Func<T, bool>> predicate)
{
IDocumentQuery<T> query = client.CreateDocumentQuery<T>(
UriFactory.CreateDocumentCollectionUri(DatabaseId, CollectionId),
new FeedOptions { MaxItemCount = -1 })
.Where(predicate)
.AsDocumentQuery();
List<T> results = new List<T>();
while (query.HasMoreResults)
{
results.AddRange(await query.ExecuteNextAsync<T>());
}
return results;
}
public static async Task<Document> CreateItemAsync(T item)
{
return await client.CreateDocumentAsync(UriFactory.CreateDocumentCollectionUri(DatabaseId, CollectionId), item);
}
public static async Task<Document> UpdateItemAsync(string id, T item)
{
return await client.ReplaceDocumentAsync(UriFactory.CreateDocumentUri(DatabaseId, CollectionId, id), item);
}
public static async Task DeleteItemAsync(string id)
{
await client.DeleteDocumentAsync(UriFactory.CreateDocumentUri(DatabaseId, CollectionId, id));
}
public static void Initialize()
{
client = new DocumentClient(new Uri(ConfigurationManager.AppSettings["endpoint"]), ConfigurationManager.AppSettings["authKey"]);
CreateDatabaseIfNotExistsAsync().Wait();
CreateCollectionIfNotExistsAsync().Wait();
}
private static async Task CreateDatabaseIfNotExistsAsync()
{
try
{
await client.ReadDatabaseAsync(UriFactory.CreateDatabaseUri(DatabaseId));
}
catch (DocumentClientException e)
{
if (e.StatusCode == System.Net.HttpStatusCode.NotFound)
{
await client.CreateDatabaseAsync(new Database { Id = DatabaseId });
}
else
{
throw;
}
}
}
private static async Task CreateCollectionIfNotExistsAsync()
{
try
{
await client.ReadDocumentCollectionAsync(UriFactory.CreateDocumentCollectionUri(DatabaseId, CollectionId));
}
catch (DocumentClientException e)
{
if (e.StatusCode == System.Net.HttpStatusCode.NotFound)
{
await client.CreateDocumentCollectionAsync(
UriFactory.CreateDatabaseUri(DatabaseId),
new DocumentCollection { Id = CollectionId },
new RequestOptions { OfferThroughput = 1000 });
}
else
{
throw;
}
}
}
}
}
警告行为：
private static DocumentClient client;
您建议如何修复此 NDepend 警告？
规则说明：
此规则警告未声明为只读的静态字段。
在面向对象编程中，保存可修改状态的自然工件是实例字段。这种可变静态字段会在运行时造成对预期状态的混淆，并损害代码可测试性，因为每个测试都会重复使用相同的可变状态。
有关该主题的更多讨论可以在这里找到：http://codebetter.com/patricksmacchia/2011/05/04/back-to-basics-usage-of-static-members/
尝试将初始化移动到声明中：
private static readonly DocumentClient client = new DocumentClient( . . . . );