c# - 在 Entity Framework 中调用 AsNoTracking 的位置是否重要

Question

编写 Entity Framework 查询时在何处调用 AsNoTracking 方法是否重要？例如

var matchingCustomers = context.Customers.AsNoTracking().Where(n => n.city == "Milan").Skip(50).Take(100).OrderBy(n => n.Name).ToList();
var matchingCustomers = context.Customers.Where(n => n.city == "Milan").AsNoTracking().Skip(50).Take(100).OrderBy(n => n.Name).ToList();
var matchingCustomers = context.Customers.Where(n => n.city == "Milan").Skip(50).AsNoTracking().Take(100).OrderBy(n => n.Name).ToList();
var matchingCustomers = context.Customers.Where(n => n.city == "Milan").Skip(50).Take(100).AsNoTracking().OrderBy(n => n.Name).ToList();
var matchingCustomers = context.Customers.Where(n => n.city == "Milan").Skip(50).Take(100).OrderBy(n => n.Name).AsNoTracking().ToList();
var matchingCustomers = context.Customers.Where(n => n.city == "Milan").Skip(50).Take(100).OrderBy(n => n.Name).ToList().AsNoTracking();

我喜欢将它添加到语句的末尾，但在像这样调用 ToList 之前:

var matchingCustomers = context.Customers.Where(n => n.city == "Milan").Skip(50).Take(100).OrderBy(n => n.Name).AsNoTracking().ToList();

Answer 1

不，没关系:(source)

A new query with NoTracking applied, or the source query if NoTracking is not supported.

因此，您要么在开始时执行此操作，然后使用方法链扩展"new"查询，要么在最后执行此操作，然后获得"new"查询。只要您在执行查询之前调用它就可以了。