关于 c#:.NET Core 3 / EF.Core 3：`QueryModelGenerator`、`RelationalQueryModelVisitor` 等发生了什么

.NET Core 3 / EF.Core 3: what happened to `QueryModelGenerator`, `RelationalQueryModelVisitor` and etc

我想知道发生了什么：QueryModelGenerator、RelationalQueryModelVisitor 和 queryCompilationContext.CreateQuerymodelVisitor() 似乎都消失了。

我有以下代码，但我无法尝试将其从 2.2 转换为 .NET Core 3

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public static string ToSql<TEntity>(this IQueryable<TEntity> query, DbContext dbCtx)
{
var modelGenerator = dbCtx.GetService<IQueryModelGenerator>();
var queryModel = modelGenerator.ParseQuery(query.Expression);
var databaseDependencies = dbCtx.GetService<DatabaseDependencies>();
var queryCompilationContext = databaseDependencies.QueryCompilationContextFactory.Create(false);
var modelVisitor = (RelationalQueryModelVisitor) queryCompilationContext.CreateQueryModelVisitor();
modelVisitor.CreateQueryExecutor<TEntity>(queryModel);
var sql = modelVisitor.Queries.FirstOrDefault()?.ToString();
return sql;
}

相关讨论

在 EF 3 中不再支持。

这里是现在怎么做

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public static string ToSql<TEntity>(this IQueryable<TEntity> query)
{
var enumerator = query.Provider.Execute<IEnumerable<TEntity>>(query.Expression).GetEnumerator();
var enumeratorType = enumerator.GetType();
var selectFieldInfo = enumeratorType.GetField("_selectExpression", BindingFlags.NonPublic | BindingFlags.Instance) ?? throw new InvalidOperationException($"cannot find field _selectExpression on type {enumeratorType.Name}");
var sqlGeneratorFieldInfo = enumeratorType.GetField("_querySqlGeneratorFactory", BindingFlags.NonPublic | BindingFlags.Instance) ?? throw new InvalidOperationException($"cannot find field _querySqlGeneratorFactory on type {enumeratorType.Name}");
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;
}

在此处查看更多信息：
https://stackoverflow.com/a/51583047/196698
https://gist.github.com/rionmonster/2c59f449e67edf8cd6164e9fe66c545a#gistcomment-3059688