我可以在模板中使用DynamicParameters并在dapper中使用返回参数吗？ [英] Can I use DynamicParameters with Template and have a return parameter in dapper?

问题描述

我当前正在使用的系统使用存储过程进行所有数据访问。目前，我正在研究Dapper（到目前为止看起来不错），但我想知道是否可以使用通过Template创建的DynamicParameters对象，但可以将其中一个参数设为输出参数。例如：

The system I am currently working on uses Stored Procedures for all data access. I'm looking into Dapper at the moment (so far it looks great) but I was wondering if I can use a DynamicParameters object created using a Template but make one of the parameters an output param. For example:

SP：

CREATE PROCEDURE InsertPerson
  @ID int Output,
  @Name varchar(100),
  @DOB DateTime2
AS
--INSERT STATEMENT

SET @ID = SCOPE_IDENTITY()

POCO：

internal class Person
{
  public int ID { get; set; }
  public string Name { get; set; }
  public DateTime DOB { get; set; }
}

代码：

var procParams = new DynamicParameters(person);
connection.Execute("InsertPerson", procParams, commandType: CommandType.StoredProcedure);

// This is where i'm having the issue, can it be done?
person.ID = procParams.Get<int>("ID");

当前我收到一个错误，因为找不到密钥。有没有一种方法可以在不手动设置所有存储的procs参数的情况下获取ID输出参数？

Current I receive an error because the key was not found. Is there a way to get the ID output parameter without manually setting up all of the stored procs parameters?

推荐答案

，添加现在替换模板中的值，允许：

With a quick tweak, Add now replaces the value from a template, allowing:

public void TestProcWithOutParameter()
{
    connection.Execute(
        @"CREATE PROCEDURE #TestProcWithOutParameter
@ID int output,
@Foo varchar(100),
@Bar int
AS
SET @ID = @Bar + LEN(@Foo)");
    var obj = new
    { // this could be a Person instance etc
        ID = 0,
        Foo = "abc",
        Bar = 4
    };
    var args = new DynamicParameters(obj);
    args.Add("ID", 0, direction: ParameterDirection.Output);
    connection.Execute("#TestProcWithOutParameter", args,
                 commandType: CommandType.StoredProcedure);
    args.Get<int>("ID").IsEqualTo(7);
}

距离足够近吗？您还可以使用 ParameterDirection.ReturnValue ，既可以是预先存在的值，也可以是新值。请注意，它不不会直接更新回原始模板；该值必须从 DynamicParameters 实例中获取（如图所示）。

Is that close enough? You can also use ParameterDirection.ReturnValue, of either a pre-existing value or a new value. Note it does not update directly back into the original template; the value must be fetched from the DynamicParameters instance (as shown).

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