c# - Dapper 需要一个无参数的构造函数？

Question

我有一个类:

public class NListingsData : ListingData, IListingData
    {
        private readonly IMetaDictionaryRepository _metaDictionary;

        //Constructor.
        public NListingsData(IMetaDictionaryRepository metaDictionary)
        {
            _metaDictionary = metaDictionary;
        }

        //Overridden function from abstract base class
        public override List<Images> Photos
        {
            get
            {
                var urlFormat = _metaDictionary.GetDictionary(CommonConstants.ImagesUrlFormat, this.Key);
                var imgs = new List<Images>();

                for (var i = 0; i < PhotosCount; i++)
                {
                    imgs.Add(new Images
                    {
                        Url = string.Format(urlFormat, this.MNumber, i)

                    });
                }
                return imgs;
            }
            set { }
        }
    }

metaDictionary 由 Autofac 注入(inject)。

我正在使用 Dapper 执行查询，并尝试具体化 NListingsData。这是我正在使用的:

string sqlQuery = GetQuery(predicates); //Select count(*) from LView; select * from lView;
//Use multiple queries
            using (var multi = _db.QueryMultipleAsync(sqlQuery,
              new
              {
                  //The parameter names below have to be same as column names and same as the fields names in the function: GetListingsSqlFilterCriteria()
                  @BedroomsTotal = predicates.GetBedrooms(),
                  @BathroomsTotalInteger = predicates.GetBathrooms()
              }).Result)
            {
                //Get count of results that match the query
                totalResultsCount = multi.ReadAsync<int>().Result.Single();
                //Retrieve only the pagesize number of results

                    var dblistings = multi.ReadAsync<NListingsData>().Result; // Error is here
            }
            return dblistings;

我得到了错误

A parameterless default constructor or one matching signature (System.Guid ListingId, System.String MLSNumber, System.Int32 BedroomsTotal, System.Double BathroomsTotalInteger) is required for CTP.ApiModels.NListingsData materialization

我用来实现 dapper 的类是否必须始终是无参数的？

现在，我可以创建一个简单的 DataModel，然后映射到我的 ViewModel。但这是唯一的方法吗？

Answer 1

只需添加一个额外的私有(private)、无参数的构造函数。这将由 Dapper 挑选。