在查询EF Core 2.1时从对象中删除某些属性 [英] Remove certain properties from object upon query EF Core 2.1

问题描述

我正在尝试将所有查询的IsoDataTables的ID完全清空或完全删除，然后再将其返回到前端。这个想法是（在这种情况下）它应该作为模板，并且我不希望它将ID返回给我，也不希望它们在前端被删除。

I'm trying to null or remove the ID entirely of all the queried IsoDataTables before returning them to frontend. The idea is that it should behave (in this case) as a template and I don't want it returning the id's back to me, nor do I want them to be removed in the frontend.

var applicationType = await _context.ApplicationType
                                    .Include(m => m.IsoTableData)
                                    .AsNoTracking()
                                    .FirstOrDefaultAsync(m => m.Id == id);

if (applicationType == null)
{
    return NotFound();
}

if (applicationType.IsoTableData != null)
{
    foreach (IsoTableData isoTableData in applicationType.IsoTableData)
    {
        // error since it a not nullable primary key
        isoTableData.Id = null;
    }
}

return Ok(applicationType);

我找到了一种解决方法，可以将对象复制并返回（不保存到数据库），但是我正在寻找一个更优雅的解决方案。

I have found a workaround in which I duplicate the objects and return them (without saving to DB) but I'm looking for a more elegant solution.

推荐答案

我的方法是创建一个复制构造函数（或者基本上是一个复制构造函数）。具有所需字段的对象的新实例）；我选择了一个复制构造函数，因为这种逻辑在其他地方也同样适用。另一个类似的解决方案是创建一个DTO对象，但是我在这里不需要它。是否有改善？

The way I did it was create a copy constructor (or basically, a new instance of an object) with the desired fields; I chose a copy constructor as this logic is recurent in other places as well. Another similar solution is creating a DTO object, but I don't need it here. Any improvements?

//in IsoFileApplicationType.cs
public IsoFileApplicationType(IsoFileApplicationType isoFileApplicationType)
{
    Id = null
    FullName = isoFileApplicationType.FullName;
    Name = isoFileApplicationType.Name;
    (...)


    foreach (IsoTableData isoTableData in isoFileApplicationType.IsoTableData)
    {
        IsoTableData.Add(IsoTableData(isoTableData));
    }
}

//in IsoTableData.cs
public IsoTableData(IsoTableData isoTableData)
{
    Id = null;
    Data = isoTableData.Name;
    Age = isoTableData.Age;
    (...)
}

// in CRUD controller
var applicationType = await _context.ApplicationType
                                   .Include(m => m.IsoTableData)
                                   .AsNoTracking()
                                   .FirstOrDefaultAsync(m => m.Id == id);

if (applicationType == null)
{
    return NotFound();
}
IsoFileApplicationType newIsoFileApplicationType = IsoFileApplicationType(applicationType);
return Ok(newIsoFileApplicationType);

这篇关于在查询EF Core 2.1时从对象中删除某些属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！