Crystal Report Set Parameter Value

I'm trying to create a Crystal Report but i get the error of - invalid index (Exception from HRESULT: 0x8002000B).
I drag the parameters from Database fields but it's unrecognize them when i write in the code:

reportName.SetParameterValue("nameOfField",value)

unless i drag the parameters from the Parameters fields (i can't have fields in the parameters field).

Any idea how can i create it with no need to the Perameters field?

Thanks for the help!