Question

我有一个名为＆＃34; Space＆＃34;在里面它有＆＃34;图像＆＃34;。 Images具有int的排序属性。我试图看看是否有一个简单的linq可以交换订单值。

public class Space
{
    public int SpaceId { get; set; }
    public virtual ICollection<SpaceImage> Images { get; set; }
}

public class SpaceImage
{
    public int SpaceImageId { get; set; }
    public byte[] Image { get; set; }
    public byte[] ImageThumbnail { get; set; }
    public string ContentType { get; set; }
    public int Ordering { get; set; }
}

离。一个图像可能有3个订单而另一个图像有6个，我想为这些图像中的每一个交换这两个数字

public void Swap(int spaceId, int old, int new)
{
    //swap 3 and 6 for the ordering value for the two spaceImages that contain these values where spaceId is spaceId
}

Answer 1

通常，LINQ将用于查询。您可以使用它来查找适当的SpaceImage实例，然后适当地设置值：

// Assuming this is a method in the Space class
public void Swap(int oldOrder, int newOrder)
{
    var oldInst = this.Images.FirstOrDefault(si => si.Ordering == oldOrder);
    var newInst = this.Images.FirstOrDefault(si => si.Ordering == newOrder);

    if (oldInst != null && newInst != null)
    {
        oldInst.Ordering = newOrder;
        newInst.Ordering = oldOrder;
    }
    else
    {
        // There weren't matching images - handle that case here
    }
}

我该如何交换两个子实体值

1 个答案: