"viewForTableColumn" vs "objectValueForTableColumn"

— All NSTableViews use NSTableColumn for their columns.

— There are two ways of showing content in a table column:

The old way uses subclasses of NSCell (like NSTextFieldCell), called a "NSCell-based table view". The new way uses NSTableCellView, called a "view-based table view". You should always use a view-based table view, and never the old way. (The old way is supported so that existing code doesn't stop working.)

— In a view-based table view, you can still use "objectValueForTableColumn", but you don't have to. Your table cells (NSTableCellView) has an "objectValue" property, that must be made to refer to an object that supplies data to the controls inside the table cell (buttons, text fields, etc). There are three ways of doing that:

1. In your "viewForTableColumn" method, after you create the cell, you can simply set the property:

     NSTableCellView *cellView = [tableView makeViewWithIdentifier:tableColumn.identifier owner:self];
     cellView.objectValue = …

2. In your data source, you can implement "objectValueForTableColumn", and return the desired objectValue.

3. You can use bindings.

Using #1 is probably the easiest way of doing this.

>> The function "NSTableCellView *cellView = [tableView makeViewWithIdentifier:tableColumn.identifier owner:self];" gives me an "nil" cell.

It's hard to say what might be wrong. The most likely reason is that your table column identifier does match the cell identifier in your prototype cell. If you're creating your own table columns, you must set their identifier to match the table cell(s) you are going to use in that column.

Thank you very much for your reply.

I can supply you more explanation.

In my "NSTableView" I want to show the components of the path of a file (5 or 6 components (fields)).

In IB I create two columns. I create the others by program:

nbcMax = 6;

for (NSInteger col = [[tableView tableColumns] count]; col < nbcMax; col++)

{

NSTableColumn *tc = [[NSTableColumn alloc] initWithIdentifier:[NSString stringWithFormat:@"tc%ld", col]];

[[tc headerCell] setStringValue:[NSString stringWithFormat:@"%ld", col]];

[tableView addTableColumn:tc];

}

With "viewForTableColumn" only the first two columns, created with IB, are filled. The others exist but are empty :

- (NSView *)tableView:(NSTableView *)tableView viewForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row

{

NSTableCellView *cellView = [tableView makeViewWithIdentifier:tableColumn.identifier owner:self];

NSArray *array = list[row];

NSInteger col = [[tableView tableColumns] indexOfObject:tableColumn];

if (col < [array count])

{

NSString *str = [array objectAtIndex:col];

NSLog(@"col : %ld - texte : %@", col, str);

if (col < [array count])

cellView.textField.stringValue = str;

}

return cellView;

}

If I create all columns (6) in IB, it works very well but I do not know the number of columns which I shall need.

If you have an idea ... Thanks in advance.

You can't do that. A table view is completely view-based or completely NSCell-based, and cannot be a mixture of the two. If you implement the "tableView:viewForTableColumn:row:" delegate method, the table view is view-based.

>> If I create all columns (6) in IB, it works very well but I do not know the number of columns which I shall need.

Create a table with 6 columns, then programmatically remove the columns you don't need. This is much easier than creating a table with 2 columns and adding more.

Thank you very much.

I am going to follow your recommendation but I do not understand why it works very well with 'tableView:objectValueForTableColumn'.