NSTableViewDataSource Protocol Reference

Discussion

An instance of NSTableView uses this method to determine how many rows it should create and display. Your numberOfRowsInTableView: implementation is called very frequently, so it must be efficient.

Both view-based table views and cell-based table views must implement this method.

Discussion

The data source should incorporate the data from the dragging pasteboard in the implementation of this method. You can get the data for the drop operation from info using the draggingPasteboard method.

To accept a drop on the second row, row would be 2 and operation would be NSTableViewDropOn. To accept a drop below the last row, row would be [aTableView numberOfRows] and operation would be NSTableViewDropAbove.

Discussion

This delegate method can be used to determine when the dragging source operation ended at a specific location, such as the trash, by checking for an operation of NSDragOperationDelete. .

Discussion

Implement this method to know when the dragging session is about to begin and to potentially modify the dragging session.

The dragged item order will directly match the pasteboard writer array used to begin the dragging session with the NSView method beginDraggingSessionWithItems:event:source:. Hence, the order is deterministic, and can be used in tableView:acceptDrop:row:dropOperation: when enumerating the NSDraggingInfo pasteboard classes.

Discussion

This method is called when a destination has accepted a promise drag.

For more information on file promise dragging, see documentation on the NSDraggingSource protocol and namesOfPromisedFilesDroppedAtDestination:.

Discussion

tableView:objectValueForTableColumn:row: is called each time the table cell needs to be redisplayed, so it must be efficient.

Discussion

This method is required for multi-image dragging.

If this method is implemented, then tableView:writeRowsWithIndexes:toPasteboard: will not be called.

Discussion

This method is intended for use with cell-based table views, it must not be used with view-based table views. Instead target/action is used for each item in the view cell.

Discussion

The data source typically sorts and reloads the data, and adjusts the selections accordingly. If you need to know the current sort descriptors and the data source does not manage them itself, you can get the current sort descriptors by sending aTableView a sortDescriptors message.

Discussion

Required for multi-image dragging. Typically this will involve invoking enumerateDraggingItemsWithOptions:forView:classes:searchOptions:usingBlock: on the draggingInfo parameter value and setting the draggingItem object’s imageComponentsProvider to a proper image based on the content.

For view-based table views, you can use the NSTableCellView method draggingImageComponents. For cell-based TableViews, use the NSCell method draggingImageComponentsWithFrame:inView:.

Discussion

The data source may “retarget” a drop if desired by calling setDropRow:dropOperation: and returning something other than NSDragOperationNone. One may choose to retarget for various reasons (e.g. for better visual feedback when inserting into a sorted position).

To propose a drop on the second row, row would be 2 and operation would be NSTableViewDropOn. To propose a drop below the last row, row would be [aTableView numberOfRows] and operation would be NSTableViewDropAbove.

Discussion

Invoked by aTableView after it has been determined that a drag should begin, but before the drag has been started.

To refuse the drag, return NO. To start a drag, return YES and place the drag data onto pboard (data, owner, and so on). The drag image and other drag-related information will be set up and provided by the table view once this call returns with YES.