Return parameter of a SQL Store procedure

[Hugo Lefevre]

Dear,

I have a problem : I have a database which contains my data of hardware. The
Id is a varchar and I want at my filling form that my user know which is the
last one. So I made a store procedure in SQL Server with a input parameter
(to select the right hardware e.g. PC for a computer, CD for cdrom, etc) and
the last code would I have become with a return parameter. But when I
execute my program I get an exception :

Parameter 1: '@HdType' of type: String, the property Size has an invalid
size: 0

What do I wrong ?

Thank you very much

Hugo Lefevre

*************** *************** *************** *************** *************** *
*************** *************** *****
Below you find the code and the construction in SQL Server :

the code in C# to execute the store procedure :
-------------------------------------------------

string HardwareType ="'PC%'"

public void DbTriggerHardwa re(string HardwareType, out string NieuwId)
{
try
{
Database
DbLogon = new Database();
SqlConnection
conn = DbLogon.Opent() ;
SqlCommand
cmd = conn.CreateComm and();

cmd.CommandType = CommandType.Sto redProcedure;

cmd.CommandText ="TriggerHardwa re";
SqlParameter
ParInput1 = cmd.Parameters. Add("@HdType", SqlDbType.VarCh ar);

ParInput1.Direc tion = ParameterDirect ion.Input;

ParInput1.Value = HardwareType;
SqlParameter
parReturn = cmd.Parameters. Add("@HdType", SqlDbType.VarCh ar);

parReturn.Direc tion = ParameterDirect ion.Output;

cmd.ExecuteRead er();
NieuwId
=(cmd.Parameter s["@HdType"].ToString());
conn.Close();
}
catch (System.Excepti on e)
{
throw new
System.Argument NullException(" ", e.Message);
}

}

The procedure of the store procedure in SQL Server :
------------------------------------------------------

CREATE PROCEDURE TriggerHardware
(
@HdType varchar(8)
)
AS
declare @HardwareId varchar(8)
select @HardwareId = max(Ha_Id)
from Hardware
where Ha_Id like @HdType
return @HardwareId
GO

Construction of the Table Hardware :
--------------------------------------

Ha_Id varchar(8)
Ha_Type varchar(50)
Ha_Snr varchar(20)

The data of the Table Hardware :
--------------------------------------
Ha_IdHa_TypeHa_ Snr
CD000001cd-dvd writer123344444 3322
PC000001draagba ar 2347678899999
PC000002Acer desktop43344566 77665

[Miha Markic [MVP C#]]

Hi Hugo,

Try using ParameterDirect ion.ReturnValue and ExecuteNonQuery ().

--
Miha Markic [MVP C#] - RightHand .NET consulting & development
miha at rthand com
www.rthand.com

"Hugo Lefevre" <hu**********@b elgacom.net> wrote in message
news:40******** **************@ news.skynet.be. ..

Dear,

I have a problem : I have a database which contains my data of hardware. The Id is a varchar and I want at my filling form that my user know which is the last one. So I made a store procedure in SQL Server with a input parameter
(to select the right hardware e.g. PC for a computer, CD for cdrom, etc) and the last code would I have become with a return parameter. But when I
execute my program I get an exception :

Parameter 1: '@HdType' of type: String, the property Size has an invalid
size: 0

What do I wrong ?

Thank you very much

Hugo Lefevre

*************** *************** *************** *************** *************** * *************** *************** *****
Below you find the code and the construction in SQL Server :

the code in C# to execute the store procedure :
-------------------------------------------------

string HardwareType ="'PC%'"

public void DbTriggerHardwa re(string HardwareType, out string NieuwId)
{
try
{
Database
DbLogon = new Database();
SqlConnection conn = DbLogon.Opent() ;
SqlCommand
cmd = conn.CreateComm and();

cmd.CommandType = CommandType.Sto redProcedure;

cmd.CommandText ="TriggerHardwa re";
SqlParameter ParInput1 = cmd.Parameters. Add("@HdType", SqlDbType.VarCh ar);

ParInput1.Direc tion = ParameterDirect ion.Input;

ParInput1.Value = HardwareType;
SqlParameter
parReturn = cmd.Parameters. Add("@HdType", SqlDbType.VarCh ar);

parReturn.Direc tion = ParameterDirect ion.Output;

cmd.ExecuteRead er();
NieuwId
=(cmd.Parameter s["@HdType"].ToString());
conn.Close(); }
catch (System.Excepti on e)
{
throw new
System.Argument NullException(" ", e.Message);
}

}

The procedure of the store procedure in SQL Server :
------------------------------------------------------

CREATE PROCEDURE TriggerHardware
(
@HdType varchar(8)
)
AS
declare @HardwareId varchar(8)
select @HardwareId = max(Ha_Id)
from Hardware
where Ha_Id like @HdType
return @HardwareId
GO

Construction of the Table Hardware :
--------------------------------------

Ha_Id varchar(8)
Ha_Type varchar(50)
Ha_Snr varchar(20)

The data of the Table Hardware :
--------------------------------------
Ha_IdHa_TypeHa_ Snr
CD000001cd-dvd writer123344444 3322
PC000001draagba ar 2347678899999
PC000002Acer desktop43344566 77665