Dapper.NET 在“类列表”中填写一个类

本文关键字：一个 NET 列表 Dapper 类列表 | 更新日期: 2023-09-27 18:31:32

我是新手 Dapper.NET 有点坚持这一点。我正在尝试填充一个类，该类具有来自多行结果集的另一个类。

# 数据库 SP> 

SELECT b.BuildingId, b.BuildingName, b.Wood, b.Food, b.Stone, b.Gold FROM UserBuildings ub, Buildings b WHERE b.BuildingId = ub.BuildingId AND UserId = @UserId

# 代码>

    using (IDbConnection connection = OpenConnection())
    {
        List<Building.Building> buildings = new List<Building.Building>();
        var multi = connection.QueryMultiple<Building.Building, Resource.Resource>("UserBuildingGet", new { UserId = UserId }, commandType: CommandType.StoredProcedure).ToList();
        building.Resource = multi.Read<Resource.Resource>().Single();
        return building;
    }

# 类> 

public class Building
{
    private int _BuildingId;
    private string _BuildingName;
    private Resource.Resource _Resource;
public int BuildingId
{
    get { return _BuildingId; }
    set { _BuildingId = value; }
}
public string BuildingName
{
    get { return _BuildingName; }
    set { _BuildingName = value; }
}
public Resource.Resource Resource
{
    get { return _Resource; }
    set { _Resource = value; }
}
public Building(int BuildingId, string BuildingName, Resource.Resource Resource)
{
    this.BuildingId = BuildingId;
    this.BuildingName = BuildingName;
    this.Resource = Resource;
}
}
public class Resource
{
    private int _Wood;
    private int _Food;
    private int _Stone;
    private int _Gold;
public int Wood
{
    get { return _Wood; }
    set { _Wood = value; }
}
public int Food
{
    get { return _Food; }
    set { _Food = value; }
}
public int Stone
{
    get { return _Stone; }
    set { _Stone = value; }
}
public int Gold
{
    get { return _Gold; }
    set { _Gold = value; }
}
public Resource(int Wood, int Food, int Stone, int Gold)
{
    this.Wood = Wood;
    this.Food = Food;
    this.Stone = Stone;
    this.Gold = Gold;
}

}

Dapper.NET 在“类列表”中填写一个类

您的代码需要定义分隔数据的内容。使用 GridReader.Read 的 splitOn 参数 

var buildings = new List<Building.Building>();
using (IDbConnection connection = OpenConnection())
{
    using(var reader = connection.QueryMultiple("UserBuildingGet",
                                                new { UserId = UserId },
                                                commandType: CommandType.StoredProcedure))
    {
        var building = reader.Read<Building.Building,
                                   Resource.Resource,
                                   Building.Building>
            ((b, r) => { b.Resource = r; return b; }, splitOn: "Wood");
        buildings.AddRange(building);
    }
}
return buildings;

请参阅：有没有办法在 Dapper 中同时使用 MultiMapping 和 QueryMultiple？

样本：

public class Building
{
    public int BuildingId { get; set; }
    public string BuildingName { get; set; }
    public Resource Resource { get; set; }
    public override string ToString()
    {
        return string.Format("Id: {0} Name: {1} Resource: {2}", BuildingId, BuildingName, Resource);
    }
}
public class Resource
{
    public int Wood { get; set; }
    public int Food { get; set; }
    public int Stone { get; set; }
    public int Gold { get; set; }
    public override string ToString()
    {
        return string.Format("Wood: {0} Food: {1} Stone {2} Gold {3}", Wood, Food, Stone, Gold);
    }
}
var sql = @"SELECT 1 AS BuildingId, 'tower' AS BuildingName, 1 AS Wood, 1 AS Food, 1 AS Stone, 1 AS Gold
            UNION ALL
            SELECT 2 AS BuildingId, 'shed' AS BuildingName, 1 AS Wood, 1 AS Food, 1 AS Stone, 1 AS Gold";
var buildings = new List<Building>();
using(var connection = GetOpenConnection())
{
    using(var reader = connection.QueryMultiple(sql))
    {
        var building = reader.Read<Building, Resource, Building>(
            (b, r) => { b.Resource = r; return b; }, splitOn: "Wood");
        buildings.AddRange(building);
    }
}
foreach(var building in buildings)
{
    Console.WriteLine(building);
}
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