Asp.net MVC4 CodeFirst 使用EFTracingProvider
一、关于EFTracingProvider
EFTracingProvider相关信息见作者博客:关于EFTracingProvider
EFTracingProvider Demo下载地址:Tracing and Caching Provider Wrappers for Entity Framework 4
EFTracingProvider 相关问题讨论:DISCUSSIONS
EFTracingProvider Nuget安装:Entity Framework Tracing Provider 1.0.0
二、如何在CodeFirst模式下使用EFTracingProvider
通过查阅的资料发现,给出的EFTracingProvider示例大都是在模型优先的模式下使用的,少有代码优先模式下的例子,不过好在在(DISCUSSIONS)里发现了答案。
现将CodeFirst模式下的使用方法做一总结,以供参考。
1、Web.config配置,添加如下配置。
<appSettings> <!--turn on/off EFTracing--> <add key="EFTracingProvider:Enabled" value="true" /> <!-- write log messages to the console. --> <add key="EFTracingProvider.logToConsole" value="false" /> <!-- append log messages to the specified file --> <add key="EFTracingProvider.logToFile" value="E:\sqllog.txt" /> </appSettings>
<system.data> <DbProviderFactories> <add name="EF Caching Data Provider" invariant="EFCachingProvider" description="Caching Provider Wrapper" type="EFCachingProvider.EFCachingProviderFactory, EFCachingProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=def642f226e0e59b" /> <add name="EF Tracing Data Provider" invariant="EFTracingProvider" description="Tracing Provider Wrapper" type="EFTracingProvider.EFTracingProviderFactory, EFTracingProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=def642f226e0e59b" /> <add name="EF Generic Provider Wrapper" invariant="EFProviderWrapper" description="Generic Provider Wrapper" type="EFProviderWrapperToolkit.EFProviderWrapperFactory, EFProviderWrapperToolkit, Version=1.0.0.0, Culture=neutral, PublicKeyToken=def642f226e0e59b" /> </DbProviderFactories> </system.data>
2、Global文件配置,在Application_Start()中添加如下代码:
//当启用EFTracingProvider时,不进行初始化数据库 if (string.Equals(ConfigurationManager.AppSettings["EFTracingProvider:Enabled"], "true", StringComparison.InvariantCultureIgnoreCase)) { Database.SetInitializer<JYZSContext>(null); JYZSContext.TraceEnabled = true; } else { Database.SetInitializer<JYZSContext>(new JYZSInitializer()); }
3、修改你的DbContext,主要是将构造函数中的DbConnection类型链接改为TracingConnection类型的链接。
#region Trace Mechanics public static bool TraceEnabled = false; public JYZSContext() : this("JYZSConnection") { } public JYZSContext(string nameOrConnectionString) : base(CreateConnection(nameOrConnectionString), true) { if (TraceEnabled) { ((IObjectContextAdapter)this).ObjectContext.EnableTracing(); } } private static DbConnection CreateConnection(string nameOrConnectionString) { EFTracingProviderFactory.Register(); ConnectionStringSettings connectionStringSetting = ConfigurationManager.ConnectionStrings[nameOrConnectionString]; string connectionString; string providerName; if (connectionStringSetting != null) { connectionString = connectionStringSetting.ConnectionString; providerName = connectionStringSetting.ProviderName; } else { providerName = "System.Data.SqlClient"; connectionString = nameOrConnectionString; } return CreateConnection(connectionString, providerName); } private static DbConnection CreateConnection(string connectionString, string providerInvariantName) { DbConnection connection = null; if (TraceEnabled) { connection = CreateTracingConnection(connectionString, providerInvariantName); } else { DbProviderFactory factory = DbProviderFactories.GetFactory(providerInvariantName); connection = factory.CreateConnection(); connection.ConnectionString = connectionString; } return connection; } private static EFTracingConnection CreateTracingConnection(string connectionString, string providerInvariantName) { string wrapperConnectionString = String.Format(@"wrappedProvider={0};{1}", providerInvariantName, connectionString); EFTracingConnection connection = new EFTracingConnection { ConnectionString = wrapperConnectionString }; //hook up logging here connection.CommandFinished += (sender, args) => Console.WriteLine(args.ToTraceString()); return connection; } #endregion
三、总结说明
以上代码是在我的项目中整理出来的,使用时注意修改链接字符串名称,并根据你的需要修改配置。
以代码中配置为例,当运行程序时,就可以在 E:\sqllog.txt 查看到EF生成的SQL语句了。实在是方便极了。
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