C# 具有父对象的子对象列表转换为具有子对象列表的父对象

我有一些模型设置如下：

public class Form
{
    public int FormId { get; set; }
    public virtual ICollection<SubForm> SubForms{ get; set; }
}
public class SubForm
{
    public int SubFormId { get; set; }
    public virtual Form Form {get; set;}
}

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

var formsWithChildren = subForms.GroupBy(s => s.Form.FormId)
                                .Select(g => new Form
                                {
                                    FormId = g.Key,
                                    SubForms = g.ToList()
                                }).ToList();

公共类表单
{
公共int FormId{get；set；}
公共虚拟ICollection子窗体{get；set；}
}
公共类子窗体
{
公共int子形式{get；set；}
公共虚拟表单{get；set；}
}

我有这样一份清单：

List<SubForm> subForms; <-- already populated, each subform has a form parent.

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

列表子表单；
这就是你的意思吗

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

这就是您的意思吗？
不创建新表单对象的方法：

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

方法而不创建新表单对象：

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

您可以按
FormId
进行分组，然后将分组后的子表单分配给每个新的
Form
项，如下所示：

public class Form
{
    public int FormId { get; set; }
    public virtual ICollection<SubForm> SubForms{ get; set; }
}
public class SubForm
{
    public int SubFormId { get; set; }
    public virtual Form Form {get; set;}
}

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

var formsWithChildren = subForms.GroupBy(s => s.Form.FormId)
                                .Select(g => new Form
                                {
                                    FormId = g.Key,
                                    SubForms = g.ToList()
                                }).ToList();

编辑：如果存在其他属性，则必须在对象初始值设定项中映射它们，但这可能会变得单调乏味，如果您打算在其他场景中重用此类查询，这不是最佳选项。我建议创建一个新的
表单
对象，并使用

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

如果您决定使用AutoMapper，方法将类似于此：

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

var formsWithChildren = new List<Form>();
foreach (var item in subForms.GroupBy(s => s.Form))
{
    Form f = Mapper.Map<Form, Form>(item.Key);
    f.SubForms = item.Select(s => s).ToList();
    formsWithChildren.Add(f);
}

您可以扩展equality和
GetHashCode
方法来使用属性来确定唯一性。目前，它仅依赖于
FormId
您可以通过
FormId
进行分组，然后将分组的子表单分配给每个新的
表单
项，如下所示：

public class Form
{
    public int FormId { get; set; }
    public virtual ICollection<SubForm> SubForms{ get; set; }
}
public class SubForm
{
    public int SubFormId { get; set; }
    public virtual Form Form {get; set;}
}

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

var formsWithChildren = subForms.GroupBy(s => s.Form.FormId)
                                .Select(g => new Form
                                {
                                    FormId = g.Key,
                                    SubForms = g.ToList()
                                }).ToList();

编辑：如果存在其他属性，则必须在对象初始值设定项中映射它们，但这可能会变得单调乏味，如果您打算在其他场景中重用此类查询，这不是最佳选项。我建议创建一个新的
表单
对象，并使用

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

如果您决定使用AutoMapper，方法将类似于此：

        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();

var formsWithChildren = new List<Form>();
foreach (var item in subForms.GroupBy(s => s.Form))
{
    Form f = Mapper.Map<Form, Form>(item.Key);
    f.SubForms = item.Select(s => s).ToList();
    formsWithChildren.Add(f);
}

您可以扩展equality和
GetHashCode
方法来使用属性来确定唯一性。目前它只依赖于
FormId
子表单。选择（i=>i.Form）。Distinct（）
，可能？
子表单。选择（i=>i.Form）。Distinct（）
，可能？这会将相关子表单放在每个表单下吗？这会将相关子表单放在每个表单下吗？如果
表单中有其他属性怎么办？它们不会被复制如果
表单中有其他属性怎么办？它们不会被复制
        //Populate subForms list of the forms
        subForms.GroupBy(x => x.Form).ForEach(x => x.Key.SubForms = x.ToList());
        //Select forms
        var forms = subForms.Select(x => x.Form).Distinct().ToList();