- UploadFile_Controller.cls
- This class uses Attachment object and associates it to a parent record. Associate object is trasient because of 135KB View State restriction in Visualforce.
- After file upload, a message is generated which will be sent to Lightning Component to inform users of success or failure or upload.
- UploadFilePage.page
- This page will exchange messages with Lightning Component
- Once the page loads, Visualforce sends a message to the Lightning component that the page was successfully loaded.
- The Lightning component has no way to know when the iFrame is loaded and when to send data for the map.
- If we try to send data before the receiving iFrame is ready, then we get an error.
- When a file has been selected in the form, Visualforce will send another message to Lightning Component
- Lightning Component uses this enable/disable submit button
- After file has been uploaded, Visualforce will send a message to Lightning Component indicating success or failure.
- UploadFileContainer.cmp
- This component can be inserted on any sObject
- Current record ID will be sent to Visualforce to use as ParentID when file is uploaded
- Once a file has been uploaded, a UI message will be displayed
