Hi,
Please, correct me if I am wrong.
You have a form - one of the fields is the ItemID and you want to get the submitted value of this field to the URL query string parameter?
If so, this would require bit more coding in the code behind. You will need to access the BasicForm and get the data from given form fields and add the value to the URL using C#.
To get the value from the form you can use e.g. (this is code sample from accessing a bizform field in the code behind):
viewBiz.BasicForm.GetDataValue("FirstName");
This
webinar talks about how the Form engine works - if you will have some time some day, I would recommend watching it.
Best regards,
Juraj Ondrus