Dapper: How to get return value ( output value) by call stored procedure

使用Dapper 执行存储过程插入一条数据，同时返回主键

Dapper 的参数类型有以下四种 System.Data.ParameterDirection

    public enum ParameterDirection
    {

        Input = 1,

        Output = 2,

        InputOutput = 3,

        ReturnValue = 6
    }

Method 1 Use ParameterDirection.ReturnValue

##### key:

return @@IDENTITY

p.Add("@ID", dbType: DbType.Int32, direction:ParameterDirection.ReturnValue);

var id = p.Get("@tID");

MyTabel：

CREATE TABLE [dbo].[WorkLog](
	[LogID] [bigint] IDENTITY(1,1) NOT NULL,
	[TypeID] [int] NOT NULL,
	[InsertDate] [datetime2](7) NOT NULL,
	[Description] [nvarchar](max) NULL,
	[UserName] [nvarchar](250) NULL,
	[StatusId] [int] NULL
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

Store Procedure:

CREATE proc [dbo].[InsertLogAndReturnID]
   @TypeID INT ,
   @Description nvarchar(max),
   @UserName nvarchar(250)
   AS
  Begin
    declare @TestID INT

     INSERT INTO [dbo].[WorkLog]
           ( [TypeID]
           ,[InsertDate]
           ,[Description]
           ,[UserName])
     VALUES
           (
           @TypeID
           , GETDATE()
           , @Description
           ,@UserName )

	return @@IDENTITY
  END
GO

C# code:

var spName = "[dbo].[InsertLogAndReturnID]";

 using (SqlConnection objConnection = new SqlConnection(Util.ConnectionString))
 {
    objConnection.Open();
    DynamicParameters p = new DynamicParameters();

    p.Add("@ID", dbType: DbType.Int32, direction: ParameterDirection.ReturnValue);
    p.Add("@TypeID", 1);
    p.Add("@Description", "TEST1");
    p.Add("@UserName", "stone");

    var row = SqlMapper.Execute(objConnection, spName, p, commandType: CommandType.StoredProcedure);
     var id  = p.Get<Int32>("@ID");

      objConnection.Close();
   }

Method 2 Use ParameterDirection.Output

##### Stored Procedure
```
CREATE proc [dbo].[InsertLogAndReturnID]
@TypeID INT ,
@Description nvarchar(max),
@UserName nvarchar(250),
@ID INT OUTPUT
AS
Begin
declare @TestID INT

 INSERT INTO [dbo].[WorkLog]
       ( [TypeID]
       ,[InsertDate]
       ,[Description]
       ,[UserName])
 VALUES
       (
       @TypeID
       , GETDATE()
       , @Description
       ,@UserName )

SELECT @ID = @@IDENTITY

END

GO

##### C# Code

var spName = "[dbo].[InsertLogAndReturnID]";

using (SqlConnection objConnection = new SqlConnection(Util.ConnectionString))

{

objConnection.Open();

DynamicParameters p = new DynamicParameters();

p.Add("@TestID", dbType: DbType.Int32, direction: ParameterDirection.Output);
p.Add("@TypeID", 1);
p.Add("@Description", "TEST1");
p.Add("@UserName", "stone");

var row = SqlMapper.Execute(objConnection, spName, p, commandType: CommandType.StoredProcedure);
 var id  = p.Get<Int32>("@TestID");

  objConnection.Close();

}