编写自己的dapper lambda扩展-使用篇

前言

这是针对dapper的一个扩展，支持lambda表达式的写法，链式风格让开发者使用起来更加优雅、直观。现在暂时只有MsSql的扩展，也没有实现事务的写法，将会在后续的版本补充。

这是个人业余的开源小项目，如果大家有更好的实现方式和好的建议欢迎拍砖

本项目已经在github上开源了：Sikiro.DapperLambdaExtension.MsSql

去年写了《整理自己的.net工具库》，里面提供的源码重新发布到了github并用新的项目名Sikiro.Tookits

这两个项目都发布到Nuget上了，可以在Nuget搜索Sikiro可以全部查看到

另外该项目会用到一些表达式树的知识，如果有兴趣的朋友可以先去了解，我之前也写过一篇简单的文章《表达式树的解析.》

下面是简单的使用介绍

开始

Nuget

你可以运行以下下命令在你的项目中安装 Sikiro.DapperLambdaExtension.MsSql。

PM> Install-Package Sikiro.DapperLambdaExtension.MsSql

SqlConnection

var con = new SqlConnection("Data Source=192.168.13.46;Initial Catalog=SkyChen;Persist Security Info=True;User ID=sa;Password=123456789");

定义User

[Table("SYS_USER")]
public class SysUser
{
    /// <summary>
    /// 主键
    /// </summary>
    [Key]
    [Required]
    [StringLength(32)]
    [Display(Name = "主键")]
    [Column("SYS_USERID")]
    public string SysUserid { get; set; }

    /// <summary>
    /// 创建时间
    /// </summary>
    [Required]
    [Display(Name = "创建时间")]
    [Column("CREATE_DATETIME")]
    public DateTime CreateDatetime { get; set; }

    /// <summary>
    /// 邮箱
    /// </summary>
    [Required]
    [StringLength(32)]
    [Display(Name = "邮箱")]
    [Column("EMAIL")]
    public string Email { get; set; }

    /// <summary>
    /// USER_STATUS
    /// </summary>
    [Required]
    [Display(Name = "USER_STATUS")]
    [Column("USER_STATUS")]
    public int UserStatus { get; set; }
}

Insert

con.CommandSet<SysUser>().Insert(new SysUser
{
    CreateDatetime = DateTime.Now,
    Email = "[e-mail]",
    SysUserid = Guid.NewGuid().ToString("N"),
    UserName = "chengong",
});

当不存在某条件记录Insert

con.CommandSet<SysUser>().IfNotExists(a => a.Email == "[e-mail]").Insert(new SysUser
{
    CreateDatetime = DateTime.Now,
    Email = "[e-mail]",
    SysUserid = Guid.NewGuid().ToString("N"),
    UserName = "chengong",
});

UPDATE

您可以根据某个条件把指定字段更新

con.CommandSet<SysUser>().Where(a => a.Email == "[e-mail]").Update(a => new SysUser { Email = "[e-mail]" });

也可以根据主键来更新整个实体字段信息

User.Email = "[e-mail]";
condb.CommandSet<SysUser>().Update(User);

DELETE

您可以根据条件来删除数据

con.CommandSet<SysUser>().Where(a => a.Email == "[e-mail]").Delete()

QUERY

GET

获取过滤条件的一条数据（第一条）

con.QuerySet<SysUser>().Where(a => a.Email == "[e-mail]").Get()

TOLIST

当然我们也可以查询出符合条件的数据集

con.QuerySet<SysUser>().Where(a => a.Email == "[e-mail]").OrderBy(b => b.Email).Top(10).Select(a => a.Email).ToList();

PAGELIST

还有分页

con.QuerySet<SysUser>().Where(a => a.Email == "[e-mail]")
                 .OrderBy(a => a.CreateDatetime)
                 .Select(a => new SysUser { Email = a.Email, CreateDatetime = a.CreateDatetime, SysUserid = a.SysUserid })
                 .PageList(1, 10);

UPDATESELECT

先更新再把结果查询出来

con.QuerySet<SysUser>().Where(a => a.Email == "[e-mail]")
                .OrderBy(a => a.CreateDatetime)
                .Select(a => new SysUser { Email = a.Email })
                .UpdateSelect(a => new SysUser { Email = "[e-mail]" });

事务功能

con.Transaction(tc =>
{
    var sysUserid = tc.QuerySet<SysUser>().Where(a => a.Email == "[e-mail]").Select(a => a.SysUserid).Get();

    tc.CommandSet<SysUser>().Where(a => a.SysUserid == sysUserid).Delete();

    tc.CommandSet<SysUser>().Insert(new SysUser
    {
        CreateDatetime = DateTime.Now,
        Email = "[e-mail]",
        Mobile = "13536059332",
        RealName = "大笨贞",
        SysUserid = Guid.NewGuid().ToString("N"),
        UserName = "fengshuzhen",
        UserStatus = 1,
        UserType = 1,
        Password = "asdasdad"
    });
});

最后来一个完整的DEMO

using (var con = new SqlConnection("Data Source=192.168.13.46;Initial Catalog=SkyChen;Persist Security Info=True;User ID=sa;Password=123456789"))
{
    con.CommandSet<SysUser>().Insert(new SysUser
    {
        CreateDatetime = DateTime.Now,
        Email = "[e-mail]",
        SysUserid = Guid.NewGuid().ToString("N"),
        UserName = "chengong",
    });

    var model = con.QuerySet<SysUser>().Where(a => a.Email == "[e-mail]").Get();

    con.CommandSet<SysUser>().Where(a => a.SysUserid == model.SysUserid)
        .Update(a => new SysUser { Email = "[e-mail]" });

    con.CommandSet<SysUser>().Where(a => a.SysUserid == model.SysUserid).Delete();
}

其他

除了简单的CURD还有Count、Sum、Exists

结束

第一个版本有未完善的地方，如果大家有很好的建议欢迎随时向我提，希望得到大家的建议后能良好的改善升级