C# .NET - i cannot add check in QB from destop app but i can add customer,account ,other

i cannot add check  in QB from destop app but i can add customer,account ,other
i can query check data but i want to add
i use time many try to do but i can't add it.

i copy and modify code c# from this site https://member.developer.intuit.com/qbsdk-current/Common/newOSR/index.html
but it not work.

i try code in your site it work https://www.nullskull.com/a/1568/c-net-application-with-quickbooks-desktop-edition.aspx
can add customer item,

but how to add check please answer me 

thank you very much