dapper中如何将map查询结果转为object列表

Question

I have a model class like:

 public class PageEditDto
 {
    public Guid PageId { get; set; }
    public string? Header { get; set; }
    public string? Content { get; set; }
    public DateTime? StartDate { get; set; }
    public DateTime? EndDate { get; set; }
    public int? PageTypeId { get; set; }
    public int PublishPlaceId { get; set; }
    public List<int>? PublishPlacesList { get; set; }
    public int? SubjectTypeId { get; set; }

    public Guid? ApprovedBy { get; set; }
    public DateTime? ApprovedAt { get; set; }

    public string? PageIconPath { get; set; }
    public int? ReadQuantity { get; set; }
    
    public string? MainImage { get; set; }
    public List<string>? ImageGallery { get; set; }
}

In the result object I have several ImageGallery row connected to the PageId ie, there are multiple records having same pageId returning from the sql. I want to map these to "List<ImageGallery" property in my model class. Is there any efficient way to do it other than creating a loop and match the records having the same PageId etc.

Answer 1

You can use GroupBy on the results to project your model. Here is an example assuming result is what you get back from the Dapper query, PublishPlace is what you named the column containing the PublishPlacesList values and Image is what you named the column containing the ImageGallery values.

// group by all of the "flat" properties
var pageEdits = result.GroupBy(p => new
    {
        p.PageId, p.Header, p.Content, p.StartDate, p.Endate, p.PageTypeId,
        p.PublishPlaceId, p.SubjectTypeId, p.ApprovedBy, p.ApprovedAt,
        p.PageIconPath, p.ReadQuantity, p.MainImage
    }).Select(m => new PageEditDto
        {
            PageId = m.Key.PageId,
            Header = m.Key.Header,
            Content = m.Key.Content,
            StartDate = m.Key.StartDate,
            Endate = m.Key.Endate,
            PageTypeId = m.Key.PageTypeId,
            PublishPlaceId = m.Key.PublishPlaceId,
            SubjectTypeId = m.Key.SubjectTypeId,
            ApprovedBy = m.Key.ApprovedBy,
            ApprovedAt = m.Key.ApprovedAt,
            PageIconPath = m.Key.PageIconPath,
            ReadQuantity = m.Key.ReadQuantity,
            MainImage = m.Key.MainImage,
            PublishPlacesList = m.PublishPlace.ToList(),
            ImageGallery = m.Image.ToList()
        }).ToList();