[英]Change method data type dynamically / at runtime
I have a Sql DB with 40 tables and I built models representing each table, I am also using Dapper as my ORM...我有一个带有 40 个表的 Sql 数据库,我构建了代表每个表的模型,我还使用 Dapper 作为我的 ORM ...
I am building my CRUD statements within a DAL (data access layer) that will take myModelObj
(coming in via HTTPPost) and modelName
(coming in via URL param)我正在 DAL(数据访问层)中构建我的 CRUD 语句,它将采用
myModelObj
(通过 HTTPPost 进入)和modelName
(通过 URL 参数进入)
I also have a method ( MyMapper
) that will map my myModelObj
to my models - however the method I created is of type object
, which returns System.Object
types - what I would like to have happen is the method return the model and convert the data type of the calling method, dynamically/at runtime, to match the model type being returned... I also have a method (
MyMapper
) that will map my myModelObj
to my models - however the method I created is of type object
, which returns System.Object
types - what I would like to have happen is the method return the model and convert the调用方法的数据类型,动态/在运行时,以匹配正在返回的 model 类型...
My code:我的代码:
Controller Controller
private readonly IDbOperation _dbo;
...
...
public DataController(IDbOperation dboperation)
{
_dbo = dboperation;
}
...
[HttpPost("create/{modelName}", Name = "Generic CRUD: Create Method")]
[Produces("application/json")]
public ActionResult Create([FromBody] JObject createObject, string modelName)
{
try
{
... ... ...
object response = _dbo.CreateRecord(createObject, modelName);
// HTTP Post Body example
{
"Fullname": "Juan Carlos",
"Firstname": "Juan",
"Lastname": "Carlos",
"Salutation": "Dr.",
"Age": 30,
"CreatedOn": "2019-11-07T12:25:10"
}
DbOperation数据库操作
private readonly IDbConnector _dbConnector
...
public DbOperation(IDbConnector dbConnector)
{
_dbConnector = dbConnector;
}
public JsonResult CreateRecord(JObject model, string modelName)
{
... ... ...
var create = MyMapper(modelName, model); // <<<
... ...
try
{
using (var connection = _dbConnector.GetMsSqlConnection())
{
// https://dapper-tutorial.net/insert
var createdId = connection.Insert(create);
...
}
}
}
private object MyMapper(string modelName, JObject mod)
{
switch (modelName.ToLower())
{
case "transaction":
return JsonConvert.DeserializeObject<ModelRepoDTO.Transaction>(model.ToString());
case "items":
return JsonConvert.DeserializeObject<ModelRepoDTO.Items>(model.ToString());
case "users":
return JsonConvert.DeserializeObject<ModelRepoDTO.Users>(mod.ToString());
...
...
default:
_logger.Error("DataAccessLayer", "DbOperation", ">>> Mapping decision could not be made");
break;
}
}
DbConnector数据库连接器
public class DbConnector : IDbConnector
{
private readonly string _connectionstring;
public DbConnector(IConfiguration config)
{
_connectionstring = config.GetValue<string>("Connectionstring");
}
public SqlConnection GetMsSqlConnection()
{
SqlConnection conn = null;
try
{
conn = new SqlConnection(_connectionstring);
conn.Open();
if (conn.State != ConnectionState.Open)
{
// throw error
}
}
catch (Exception ex)
{
if (conn != null && conn.State == ConnectionState.Open)
{
conn.Close();
}
conn = null;
}
// return the connection
return conn;
}
}
(Currently) The data type coming back from MyMapper("User", {<Object from HTTP Post>})
is System.Object
because MyMapper
is of type object
(当前)从
MyMapper("User", {<Object from HTTP Post>})
返回的数据类型是System.Object
因为MyMapper
的类型是object
What I want is to have the data type dynamically changed to match the model...我想要的是动态更改数据类型以匹配 model ...
MyMapper("User", {<Object from HTTP Post>})
=> data type = User
MyMapper("User", {<Object from HTTP Post>})
=> data type = User
Keep in mind there are 40 different tables/models I can be CRUD'ing against, obviously I won't know which one is being called until runtime...请记住,我可以针对 40 个不同的表/模型进行 CRUD,显然我不会知道在运行时之前调用的是哪个表/模型......
(to complete the example) ...I take the object returned from MyMapper
and pass it to connection.insert(...);
(完成示例) ...我将 MyMapper 返回的
MyMapper
传递给connection.insert(...);
(I modified my post to show this - look at DbOperation) (我修改了我的帖子以显示这一点 - 看看 DbOperation)
Any suggestions?有什么建议么? Thoughts?
想法?
If I understand your question, you are attempting to call a third party (Dapper) generic method without foreknowledge of the generic type argument, which normally must be supplied at compile time.如果我理解您的问题,您正在尝试调用第三方(Dapper)泛型方法,而无需预知泛型类型参数,通常必须在编译时提供。
This can be accomplished via Reflection .这可以通过反射来完成。 In your wrapper class (which I believe you call "DbConnector") add a new method called "InsertDynamicObject" and code it to use Reflection to find the method definition that you wish to call.
在您的包装器 class(我相信您称之为“DbConnector”)中添加一个名为“InsertDynamicObject”的新方法,并将其编码为使用反射来查找您希望调用的方法定义。 You can then call MakeGenericMethod, passing the generic type parameters.
然后,您可以调用 MakeGenericMethod,传递泛型类型参数。 An example could look like this:
一个示例可能如下所示:
namespace Dapper //This is a stub for the Dapper framework that you cannot change
{
class DbConnection
{
public void Insert<T>(T obj)
{
Console.WriteLine("Inserting an object with type {0}", typeof(T).FullName);
}
}
}
namespace MyProgram
{
class DbConnector //Here is your DbConnector class, which wraps Dapper
{
protected readonly Dapper.DbConnection _connection = new Dapper.DbConnection();
public void InsertDynamicObject(object obj)
{
typeof(Dapper.DbConnection)
.GetMethod("Insert")
.MakeGenericMethod(new [] { obj.GetType() })
.Invoke(_connection, new[] { obj });
}
}
public class Program
{
public static void Main()
{
object someObject = "Test"; //This is the object that you deserialized where you don't know the type at compile time.
var connector = new DbConnector();
connector.InsertDynamicObject(someObject);
}
}
}
Output: Output:
Inserting an object with type System.String
Here is a link to a working example on DotNetFiddle: Link这是 DotNetFiddle 上一个工作示例的链接:链接
I think OP is trying to consume dapper insert method from Dapper's contrib lib.我认为 OP 正在尝试使用 Dapper 的 contrib lib 中的 dapper insert 方法。 Hence the generic create method.
因此,通用的创建方法。 @Op am I understanding it right?
@Op我理解对了吗?
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