I want to rethrow same exception in sql server that has been occured in my try block. I am able to throw same message but i want to throw same error.

BEGIN TRANSACTION
    BEGIN TRY
            INSERT INTO Tags.tblDomain 
            (DomainName, SubDomainId, DomainCode, Description)
            VALUES(@DomainName, @SubDomainId, @DomainCode, @Description)
            COMMIT TRANSACTION
    END TRY

    BEGIN CATCH
            declare @severity int; 
            declare @state int;

            select @severity=error_severity(), @state=error_state();

            RAISERROR(@@Error,@ErrorSeverity,@state);
            ROLLBACK TRANSACTION
    END CATCH

RAISERROR(@@Error, @ErrorSeverity, @state);

This line will show error, but i want functionality something like that. This raises error with error number 50000, but i want erron number to be thrown that i am passing @@error,

I want to capture this error no at frontend

i.e.

catch (SqlException ex)
{
if ex.number==2627
MessageBox.show("Duplicate value cannot be inserted");
}

I want this functionality. which can't be achieved using raiseerror. I dont want to give custom error message at back end.