I’m dynamically adding columns to a table view, but I’m having tremendous problems. Every time I delete all columns and add one column, it adds two! Any idea?

//Delete all columns NSArray * columnsIn = [mainView tableColumns]; for (i=0; i < [mainView numberOfColumns]; i++){ [mainView removeTableColumn:[columnsIn objectAtIndex:i]]; }

//Add a column NSTableColumn * newColumn; newColumn = [[NSTableColumn alloc] initWithIdentifier:@”eone”]; newColumn headerCell] setStringValue:[item valueForKey:@”oen”; [mainView addTableColumn:newColumn];

Again, this generates two which is really bugging me. Any help is appreciated, thanks.

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//Delete all columns NSArray * columnsIn = [mainView tableColumns]; const unsigned max = [columnsIn count]; for (i=0; i < max; ++i) { [mainView removeTableColumn:[columnsIn objectAtIndex:i]]; } . . .

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This doesn’t work either…getting an out of bounds error. Tables seem to delete fine with the other code.

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No matter what, the original code won’t work properly. As the columns are deleted, -numberOfColumns will return smaller numbers, so you never hit the end of the array.

Both versions will fail if -tableColumns returns a reference to the table’s internal array, rather than returning a copy. This is probably why the second version is getting an out-of-bounds error. The simplest solution would be one like this:

while([mainView numberOfColumns]) [mainView removeTableColumn: mainView tableColumns] objectAtIndex:0;

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On a bit of a side note, you should release your newly-created NSTableColumn after you’ve added it to your NSTableView. If you don’t, it’ll cause a memory leak when it’s removed from the table or the table is deallocated. – Bo

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Sorry about my knee jerk solution causing an out of bounds issue. I made the assumption that since - tableColumns is returning an NSArray and not a NSMutableArray (direct reference or not) that the contents would not change while removing columns. My bad for not testing before posting though, and I know ran into this in the past; Should have known better. Now, for some more untested code, I guess you could always NSArray * columnsIn = [[[mainView tableColumns] copy] autorelease] to avoid all of the method calls of the other solutions.

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Thanks for all the help, while works fine. On a side note, I do release the tableColumn but forgot to include it in the code. Thanks!