1

我已经构建了一个通用（抽象）构建器，它将为将在测试期间使用的实体构建器提供基本实现。

这是实体基类：

public abstract class Entity : IObjectState
{
    [NotMapped]
    public ObjectState ObjectState { get; set; }
}

这是IKey 接口：

public interface IKey
{
    int Id { get; set; }
}

这是Builder 类：

public abstract class Builder<T> where T : Entity, IKey, new()
{
    protected int _id { get; set; }
    protected ObjectState _objectState { get; set; }

    public Builder()
    {
        _objectState = ObjectState.Added;
    }

    public virtual Builder<T> WithId(int id)
    {
        this._id = id;
        return this;
    }

    public virtual Builder<T> HavingObjectState(ObjectState objectState)
    {
        _objectState = objectState;
        return this;
    }

    public static implicit operator T(Builder<T> builder)
    {
        return new T
        {
            Id = builder._id,
            ObjectState = builder._objectState
        };
    }
}

这是一个示例UnitBuilder实现：

public class UnitBuilder : Builder<Unit>
{
    private string _shortDescription;
    private string _longDescription;

    public UnitBuilder WithShort(string shortDescription)
    {
        _shortDescription = shortDescription;
        return this;
    }

    public UnitBuilder WithLong(string longDescription)
    {
        _longDescription = longDescription;
        return this;
    }

    public static implicit operator Unit(UnitBuilder builder)
    {
        return new Unit
        {
            Id = builder._id,
            ObjectState = builder._objectState,
            Short = builder._shortDescription,
            Long = builder._longDescription
        };
    }
}

这就是我遇到的问题：

样本

错误：

错误 CS1061“Builder”不包含“WithShort”的定义，并且找不到接受“Builder”类型的第一个参数的扩展方法“WithShort”（您是否缺少 using 指令或程序集引用？）



我了解发生了什么，但我想要一个比thirdUnit.

更新：

根据建议，我在UnitBuilder课堂上添加了以下内容：

public new UnitBuilder WithId(int id)
{
    return (UnitBuilder)base.WithId(id);
}

public new UnitBuilder WithObjectState(ObjectState objectState)
{
    return (UnitBuilder)base.WithObjectState(objectState);
}

但是现在我在基类中看不到任何意义......这必须是一个通用的通用基类问题，其他人如何处理这个问题？也许thirdUnit解决方案很优雅，但我只是对此感到困难？:)

4

2 回答 2

2

答案很简单，您的基类构建器方法必须最后调用，并且不能与您更具体的构建器类链接，因为它返回泛型。所以只需将您的代码更改为：

Unit secondUnit = new UnitBuilder()
    .WithShort("ShortDesc")
    .WithId(10);

而已！

于 2016-05-29T08:32:53.930 回答
0

这是我的最终解决方案：

public abstract class Builder<TEntity, TBuilder>
        where TEntity : Entity, IKey, new()
        where TBuilder : Builder<TEntity, TBuilder>, new()
{
    protected int _id { get; set; }
    protected ObjectState _objectState { get; set; }

    public Builder()
    {
        _objectState = ObjectState.Added;
    }

    public virtual Builder<TEntity, TBuilder> WithId(int id)
    {
        this._id = id;
        return this;
    }

    public virtual Builder<TEntity, TBuilder> WithObjectState(ObjectState objectState)
    {
        this._objectState = objectState;
        return this;
    }

    public static implicit operator TEntity(Builder<TEntity, TBuilder> builder)
    {
        return new TEntity
        {
            Id = builder._id,
            ObjectState = builder._objectState
        };
    }
}
于 2016-05-29T14:04:12.870 回答