ASP.NET MVC中如何将MainVM的列表数据迁移至DescRecordsVM？

我在MainVM视图模型中有两个列表，需要遍历这两个列表提取数据，统一添加到DescRecordsVM视图模型的Records列表中。具体映射规则如下：

• Attachments → Records：
  • Id → Id
  • documentName → Description
  • documentType → Type
• Emails → Records：
  • Id → Id
  • EmailName → Description
  • EmailType → Type

示例映射：

Attachments                         Records
ID = 5                             --> ID=5
documentName = "file.pdf"          --> Description = "file.pdf"
documentType="PDF"                 --> Type="PDF"

Emails                                 Records
ID = 7                               --> ID=7
EmailName = "Progress"               --> Description = "Progress"
EmailType="GMAIL"                    --> Type="GMAIL"

相关视图模型定义：

public class MainVM
{
    public List<AttachmentVM> Attachments { get; set; }
    public List<EmailVM> Emails{ get; set; }
}

public class AttachmentVM
{
    public Guid Id { get; set; }
    public string documentName { get; set; }
    public string documentType { get; set; }
}

public class EmailVM
{
    public Guid Id { get; set;  }
    public string EmailName{ get; set; }
    public string EmailType { get; set; }
}

目标视图模型：

public class DescRecordsVM
{
    public List<DescriptionVM> Records { get; set; }
}

public class DescriptionVM
{
    public Guid Id { get; set;  }
    public string Description{ get; set; }
    public string Type{ get; set; }
}

控制器代码（待补充逻辑）：

public async Task<ActionResult> GetCommunications(long id )
{
    var vm = new ViewModels.MainVM();
    vm.Attachments = GetAttachments(id).ToList();
    // 注意：原代码存在错误，此处应调用GetEmails(id)而非GetAttachments(id)
    vm.Emails= GetAttachments(id).ToList();

    // 此处需遍历列表，将数据填充到DescRecordsVM的Records列表中

    return PartialView("view",Records);
}

这个需求完全可以实现，下面提供几种常见的实现方式：

方式一：直接使用LINQ拼接转换 #

在控制器中直接通过LINQ将两个列表转换后合并，代码简洁直观：

public async Task<ActionResult> GetCommunications(long id )
{
    var vm = new ViewModels.MainVM();
    vm.Attachments = GetAttachments(id).ToList();
    // 修正原代码错误：获取Emails数据调用GetEmails方法
    vm.Emails = GetEmails(id).ToList();

    // 转换Attachments为DescriptionVM集合
    var attachmentRecords = vm.Attachments.Select(a => new DescriptionVM
    {
        Id = a.Id,
        Description = a.documentName,
        Type = a.documentType
    });

    // 转换Emails为DescriptionVM集合
    var emailRecords = vm.Emails.Select(e => new DescriptionVM
    {
        Id = e.Id,
        Description = e.EmailName,
        Type = e.EmailType
    });

    // 合并集合并封装到目标视图模型
    var recordsVM = new DescRecordsVM
    {
        Records = attachmentRecords.Concat(emailRecords).ToList()
    };

    return PartialView("view", recordsVM.Records);
}

方式二：封装转换方法（提升复用性） #

如果需要在多个地方复用转换逻辑，可以把转换逻辑封装成静态方法或扩展方法：

扩展方法封装 #

public static class VMConverter
{
    public static DescriptionVM ToDescriptionVM(this AttachmentVM attachment)
    {
        return new DescriptionVM
        {
            Id = attachment.Id,
            Description = attachment.documentName,
            Type = attachment.documentType
        };
    }

    public static DescriptionVM ToDescriptionVM(this EmailVM email)
    {
        return new DescriptionVM
        {
            Id = email.Id,
            Description = email.EmailName,
            Type = email.EmailType
        };
    }
}

控制器中调用示例：

public async Task<ActionResult> GetCommunications(long id )
{
    var vm = new ViewModels.MainVM();
    vm.Attachments = GetAttachments(id).ToList();
    vm.Emails = GetEmails(id).ToList();

    var recordsVM = new DescRecordsVM
    {
        Records = vm.Attachments.Select(a => a.ToDescriptionVM())
                                .Concat(vm.Emails.Select(e => e.ToDescriptionVM()))
                                .ToList()
    };

    return PartialView("view", recordsVM.Records);
}

方式三：使用AutoMapper（适合复杂映射场景） #

如果项目中有大量对象映射需求，可借助AutoMapper库简化配置：

1. 安装AutoMapper NuGet包：Install-Package AutoMapper
2. 配置映射关系：

var config = new MapperConfiguration(cfg =>
{
    cfg.CreateMap<AttachmentVM, DescriptionVM>()
       .ForMember(dest => dest.Description, opt => opt.MapFrom(src => src.documentName))
       .ForMember(dest => dest.Type, opt => opt.MapFrom(src => src.documentType));

    cfg.CreateMap<EmailVM, DescriptionVM>()
       .ForMember(dest => dest.Description, opt => opt.MapFrom(src => src.EmailName))
       .ForMember(dest => dest.Type, opt => opt.MapFrom(src => src.EmailType));
});

IMapper mapper = config.CreateMapper();

3. 控制器中使用：

public async Task<ActionResult> GetCommunications(long id )
{
    var vm = new ViewModels.MainVM();
    vm.Attachments = GetAttachments(id).ToList();
    vm.Emails = GetEmails(id).ToList();

    var attachmentRecords = mapper.Map<List<DescriptionVM>>(vm.Attachments);
    var emailRecords = mapper.Map<List<DescriptionVM>>(vm.Emails);

    var recordsVM = new DescRecordsVM
    {
        Records = attachmentRecords.Concat(emailRecords).ToList()
    };

    return PartialView("view", recordsVM.Records);
}

内容的提问来源于stack exchange，提问作者Michaelweston