I cannot get the InputOutput direction to work for a stored procedure on Azure Sql -

i have created following stored procedure in azure sql.

alter procedure [dbo].[composite_shop_getnextordreno]     @orderprefix nvarchar(50) output,     @istestmode int = 0     declare @nextordernumber int      if not exists (select top 1 [orderprefix]                     [dbo].[composite_shop_ordernumber]                     [orderprefix] = @orderprefix)     begin         insert [dbo].[composite_shop_ordernumber] (orderprefix)          values (@orderprefix)     end      update [dbo].[composite_shop_ordernumber] (readcommittedlock)     set @nextordernumber = number = number + 1     [orderprefix] = @orderprefix      select @orderprefix = @orderprefix +  replicate('0', 6 - len(rtrim(convert(nvarchar(50), @nextordernumber)))) + convert(nvarchar(50), @nextordernumber)      return 

no matter try c# have not succeeded in giving 1 parameter , getting out again modified.

intutively assume should work don't.

var param = new sqlparameter("@orderprefix",sqldbtype.nvarchar); param.value = "test"; param.direction = parameterdirection.inputoutput; cmd.parameters.add(param); 

when check param after been executed same when sending in.

i assume there must have missed.