How to create an ALV in docking container in SAP?

Wa_fieldcat is a structure used as a container for the information that has to be added to t_fieldcat.

Following Parameters are passed:                                

• *  pv_field   TYPE any for Field                               
• *  pv_tabname TYPE any for Table Name               
• *  pv_coltext TYPE any for Header Text

These variables can’t append under t_fieldcat without putting them in a unified structure.