Sql Example of parameter directions in combination with C#

parameterDirections.sql

if exists(select * from sys.procedures where name = 'test_proc')
begin
	drop procedure test_proc
end
go

create procedure test_proc
@in int,
@out int output,
@inout int output
as
begin
	print '@in was ' + convert(varchar(max), @in) + ' and set it to 11'
	set @in = 11
	print '@out was ' + convert(varchar(max), @out) + ' and set it to 22'
	set @out = 22
	print '@inout was ' + convert(varchar(max), @inout) + ' and set it to 33'
	set @inout = 33
	print 'returning 44'
	return 44
end
go

declare @in int = 1,        -- ParameterDirection.Input
        @out int = 2,       -- ParameterDirection.Output
        @inout int = 3,     -- ParameterDirection.InputOutput
        @retval int = 4     -- ParameterDirection.ReturnValue
		
exec @retval = test_proc @in = @in, @out = @out output, @inout = @inout output
select @in, @out, @inout, @retval
go

if exists(select * from sys.procedures where name = 'test_proc')
begin
	drop procedure test_proc
end
go