轉載自https://www.cnblogs.com/gskstudy/p/13306399.html

對於EFCore 3.1

using System.Linq; using System.Reflection; using System.Collections.Generic; using Microsoft.EntityFrameworkCore.Query.SqlExpressions; using Microsoft.EntityFrameworkCore.Query;

public static string ToSql(this IQueryable query) where TEntity : class { var enumerator = query.Provider.Execute<IEnumerable>(query.Expression).GetEnumerator(); var relationalCommandCache = enumerator.Private("_relationalCommandCache"); var selectExpression = relationalCommandCache.Private("_selectExpression"); var factory = relationalCommandCache.Private("_querySqlGeneratorFactory");

var sqlGenerator = factory.Create();
var command = sqlGenerator.GetCommand(selectExpression);

string sql = command.CommandText;
return sql;

}

private static object Private(this object obj, string privateField) ⇒ obj?.GetType().GetField(privateField, BindingFlags.Instance | BindingFlags.NonPublic)?.GetValue(obj); private static T Private(this object obj, string privateField) ⇒ (T)obj?.GetType().GetField(privateField, BindingFlags.Instance | BindingFlags.NonPublic)?.GetValue(obj); 　　

對於EFCore 3.0

public static string ToSql(this IQueryable query) { var enumerator = query.Provider.Execute<IEnumerable>(query.Expression).GetEnumerator(); var enumeratorType = enumerator.GetType(); var selectFieldInfo = enumeratorType.GetField("_selectExpression", BindingFlags.NonPublic | BindingFlags.Instance) ?? throw new InvalidOperationException($"cannot find field _selectExpression on type "); var sqlGeneratorFieldInfo = enumeratorType.GetField("_querySqlGeneratorFactory", BindingFlags.NonPublic | BindingFlags.Instance) ?? throw new InvalidOperationException($"cannot find field _querySqlGeneratorFactory on type "); var selectExpression = selectFieldInfo.GetValue(enumerator) as SelectExpression ?? throw new InvalidOperationException($"could not get SelectExpression"); var factory = sqlGeneratorFieldInfo.GetValue(enumerator) as IQuerySqlGeneratorFactory ?? throw new InvalidOperationException($"could not get IQuerySqlGeneratorFactory"); var sqlGenerator = factory.Create(); var command = sqlGenerator.GetCommand(selectExpression); var sql = command.CommandText; return sql; } 　　

對於EFCore 2.1.2

static class IQueryableToSql { private static readonly TypeInfo QueryCompilerTypeInfo = typeof(QueryCompiler).GetTypeInfo(); private static readonly FieldInfo QueryCompilerField = typeof(EntityQueryProvider).GetTypeInfo().DeclaredFields.First(x ⇒ x.Name == "_queryCompiler"); private static readonly FieldInfo QueryModelGeneratorField = QueryCompilerTypeInfo.DeclaredFields.First(x ⇒ x.Name == "_queryModelGenerator"); private static readonly FieldInfo queryContextFactoryField = QueryCompilerTypeInfo.DeclaredFields.First(x ⇒ x.Name == "_queryContextFactory"); private static readonly FieldInfo loggerField = QueryCompilerTypeInfo.DeclaredFields.First(x ⇒ x.Name == "_logger"); private static readonly FieldInfo DataBaseField = QueryCompilerTypeInfo.DeclaredFields.Single(x ⇒ x.Name == "_database"); private static readonly PropertyInfo DatabaseDependenciesField = typeof(Database).GetTypeInfo().DeclaredProperties.Single(x ⇒ x.Name == "Dependencies");

        public static (string sql, IReadOnlyDictionary<string, object> parameters) ToSql<TEntity>(IQueryable<TEntity> query) where TEntity : class
        {
            var queryCompiler = (QueryCompiler)QueryCompilerField.GetValue(query.Provider);
            var queryContextFactory = (IQueryContextFactory)queryContextFactoryField.GetValue(queryCompiler);
            var logger = (Microsoft.EntityFrameworkCore.Diagnostics.IDiagnosticsLogger<DbLoggerCategory.Query>)loggerField.GetValue(queryCompiler);
            var queryContext = queryContextFactory.Create();
            var modelGenerator = (QueryModelGenerator)QueryModelGeneratorField.GetValue(queryCompiler);
            var newQueryExpression = modelGenerator.ExtractParameters(logger, query.Expression, queryContext);
            var queryModel = modelGenerator.ParseQuery(newQueryExpression);
            var database = (IDatabase)DataBaseField.GetValue(queryCompiler);
            var databaseDependencies = (DatabaseDependencies)DatabaseDependenciesField.GetValue(database);
            var queryCompilationContext = databaseDependencies.QueryCompilationContextFactory.Create(false);
            var modelVisitor = (RelationalQueryModelVisitor)queryCompilationContext.CreateQueryModelVisitor();

            modelVisitor.CreateQueryExecutor<TEntity>(queryModel);
            var command = modelVisitor.Queries.First().CreateDefaultQuerySqlGenerator()
                .GenerateSql(queryContext.ParameterValues);

            return (command.CommandText, queryContext.ParameterValues);
        }
    }