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Here, you will learn how to intercept EF when it executes database commands.
EF 6 provides the ability to intercept the context using IDbCommandInterceptor before and after it performs the ExecuteNonQuery, ExecuteScalar, ExecuteReader operations to the database.
First, implement IDbCommandInterceptor as shown below:
class EFCommandInterceptor: IDbCommandInterceptor { public void NonQueryExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<int> interceptionContext) { LogInfo("NonQueryExecuted", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void NonQueryExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<int> interceptionContext) { LogInfo("NonQueryExecuting", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void ReaderExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContextt<System.Data.Common.DbDataReader> interceptionContext) { LogInfo("ReaderExecuted", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void ReaderExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<System.Data.Common.DbDataReader> interceptionContext) { LogInfo("ReaderExecuting", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void ScalarExecuted(System.Data.Common.DbCommand command, DbCommandInterceptionContext<object> interceptionContext) { LogInfo("ScalarExecuted", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } public void ScalarExecuting(System.Data.Common.DbCommand command, DbCommandInterceptionContext<object> interceptionContext) { LogInfo("ScalarExecuting", String.Format(" IsAsync: {0}, Command Text: {1}", interceptionContext.IsAsync, command.CommandText)); } private void LogInfo(string command, string commandText) { Console.WriteLine("Intercepted on: {0} :- {1} ", command, commandText); } }
You can see in the above code that IDbCommandInterceptor provides six methods to execute.
Now, you will need to configure the interceptor either by using config file or code-based configuration.
Config file:
<entityFramework> <interceptors> <interceptor type="EF6DBFirstTutorials.EFCommandInterceptor, EF6DBFirstTutorials"> </interceptor> </interceptors> </entityFramework>
Code-based config:
public class FE6CodeConfig : DbConfiguration { public FE6CodeConfig() { this.AddInterceptor(new EFCommandInterceptor()); } }
So now, we can log commands whenever DbContext executes ExecuteNonQuery, ExecuteScalar, and ExecuteReader.
Download DB First sample project for interception demo.
Entity Framework 6.0 Tutorials（5）：Command Interception
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原文地址：http://www.cnblogs.com/purplefox2008/p/5649541.html
