dapper nuget 1.7 枚举映射

发布于 2024-12-18 13:27:52 字数 1124 浏览 0 评论 0原文

我从 Nuget 升级到最新版本的 Dapper（v 1.7）后遇到了问题。

它始终返回第一个枚举成员（即，它无法映射）。

我使用 MySQL 作为数据库。

CREATE TABLE `users_roles` (
    `userId` INT(11) NOT NULL,
    `roleId` INT(11) NOT NULL,  
    KEY `user_id` (`userId`),
    KEY `role_id` (`roleId`)
);

INSERT INTO `users_roles` (`userId`, `roleId`) VALUES (1, 1);
INSERT INTO `users_roles` (`userId`, `roleId`) VALUES (2, 2);

public enum Role { 
  Anonymous = 0, Authenticate = 1, Administrator = 2
}

var role = Current.Db.Query<Role>(@"SELECT roleId as Role FROM users_roles
    WHERE userId=@id", new { id = 2 }).FirstOrDefault();

它给出了 Dapper nuget v1.6 中的预期输出。这是新版本（1.7）的正确行为吗？

更新：

在使用一些控制台应用程序和新的 mvc3 应用程序进行一些测试后，我发现当您直接映射枚举类型时，Dapper 枚举映射的行为不一致。

但是，将枚举映射为类的属性以某种方式始终返回正确的映射

public class User
{
   public int Id { get; set; }
   public Role Role { get; set; }
}

var user = Current.Db.Query<User>(@"SELECT roleId as Role, userId as Id 
    FROM users_roles
    WHERE userId=@id", new { id = 2 }).FirstOrDefault();

user.Role 的结果以某种方式返回预期的输出

原文

I've encountered an issue after I upgraded to the latest version of Dapper from Nuget (v 1.7).

It always return the first enums member (that is, it fail to maps).

I am using MySQL as the database.

CREATE TABLE `users_roles` (
    `userId` INT(11) NOT NULL,
    `roleId` INT(11) NOT NULL,  
    KEY `user_id` (`userId`),
    KEY `role_id` (`roleId`)
);

INSERT INTO `users_roles` (`userId`, `roleId`) VALUES (1, 1);
INSERT INTO `users_roles` (`userId`, `roleId`) VALUES (2, 2);

public enum Role { 
  Anonymous = 0, Authenticate = 1, Administrator = 2
}

var role = Current.Db.Query<Role>(@"SELECT roleId as Role FROM users_roles
    WHERE userId=@id", new { id = 2 }).FirstOrDefault();

It gives the expected output in Dapper nuget v1.6. Is this the correct behavior for the new version (1.7)?

Update:

After doing some testing with a few console application and fresh mvc3 appications I found that the behavior of Dapper enum mapping is inconsistent when you map the enum type directly.

However, mapping an enum as a property of a class somehow consistently returns the correct map

public class User
{
   public int Id { get; set; }
   public Role Role { get; set; }
}

var user = Current.Db.Query<User>(@"SELECT roleId as Role, userId as Id 
    FROM users_roles
    WHERE userId=@id", new { id = 2 }).FirstOrDefault();

the result of user.Role somehow returns the expected output

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吲‖鸣 2024-12-25 13:27:52

在错误修复之前，我的解决方法是使用额外条件修改 GetDeserializer 方法

||类型.IsEnum

将 struct 反序列化器用于枚举，如下所示：

        private static Func<IDataReader, object> GetDeserializer(Type type, IDataReader reader, int startBound, int length, bool returnNullIfFirstMissing)
        {
...
            if (!(typeMap.ContainsKey(type) || type.IsEnum /* workaround! */ || type.FullName == LinqBinary))
            {
                return GetTypeDeserializer(type, reader, startBound, length, returnNullIfFirstMissing);
            }
            return GetStructDeserializer(type, startBound);

        }

Until the bug is fixed my workaround is to modify GetDeserializer method with extra condition

|| type.IsEnum

to use struct deserializer for enums as follows:

        private static Func<IDataReader, object> GetDeserializer(Type type, IDataReader reader, int startBound, int length, bool returnNullIfFirstMissing)
        {
...
            if (!(typeMap.ContainsKey(type) || type.IsEnum /* workaround! */ || type.FullName == LinqBinary))
            {
                return GetTypeDeserializer(type, reader, startBound, length, returnNullIfFirstMissing);
            }
            return GetStructDeserializer(type, startBound);

        }

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