Question

我想知道如何使用LINQ执行此基本操作。我有一个更新函数，它接受一个视图模型对象，该对象具有一个属性是另一个视图模型对象的列表，我想循环这些并更新数据库。这是我的代码：

public void UpdateInspection (EditInspectonViewModel editedInspection)
    {
        //get the inspection we're editing
        Inspection inspection = _repo.GetAll<Inspection>().Single(x=>x.Id==editedInspection.Id;

        //set the values to what was passed in
        inspection.Name = editedInspection.Name;
        inspection.Description = editedInspection.Description;

        // Here is where I'm stuck (note-Damages is of type  DamageViewModel)
        foreach (var damage in editedInspection.Damages)
         {
        // How do I get a reference to the inspection record's corresponding
        // damages records?
         }

        _repo.SaveChanges();

    }

是否有LINQ语法允许我更新这些子记录中的值（即检查损坏）？

Answer 1

如果我理解你想要的东西，你可以使用Join LINQ方法，如：

public void UpdateInspection (EditInspectonViewModel editedInspection)
{
    //get the inspection we're editing
    Inspection inspection = _repo.GetAll<Inspection>().Single(x=>x.Id==editedInspection.Id;

    //set the values to what was passed in
    inspection.Name = editedInspection.Name;
    inspection.Description = editedInspection.Description;

    // Here is where I'm stuck (note-Damages is of type  DamageViewModel)
    var damages = editedInspection.Damages
                                  .Join(inspection.Damages, 
                                        d => d.Id, d => d.Id, 
                                        (vmDmg, dbDmg) => new { vmDmg, dbDmg });
    foreach (var damage in damages)
    {
        damage.dbDmg.Property = damage.vmDmg.Property;
    }

    _repo.SaveChanges();
}

用于更新对象上的集合属性的基本LINQ

1 个答案: