Adding an NSRect when a button is pushed - objective-c

Question

I am trying to add an NSRect when a button is pushed but IBAction is in one view controller while the drawing code must be in a view and for some reason the code I am using won't draw the rect here is the source for the action method in the view controller:
-(IBAction)ButtonPressed:(id)sender {
NSRect Rect = NSMakeRect(10, 10, 100, 100);
NSColor* BlackFill = [NSColor blackColor];
[BlackFill set];
NSRectFill(Rect);
NSColor* whitestroke = [NSColor whiteColor];
[whitestroke set];
NSFrameRectWithWidth(Rect, 5.0);
[rects addObject:[NSValue valueWithRect:Rect]];
[self.rectView setNeedsDisplay:YES];
}
And the source for the drawing code in the view:
-(void)drawRect:(NSRect)dirtyRect {
//heres the part where I want to draw the NSRect but it does not work
if ([datasource conformsToProtocol:#protocol(MainViewDatasource)]) {
NSLog(#"DataSource conforms to protocol:MainViewDatasource");
NSUInteger numRects = [datasource numberOfRectsInView:self];
for (NSUInteger i = 0; i < numRects < 800; i++) {
NSRect currentRect = [datasource rectangleView:self rectAtIndex:i];
NSFrameRect(currentRect);
}
if (numRects >= 800) {
NSAlert* alert = [[NSAlert alloc] init];
[alert setAlertStyle:NSInformationalAlertStyle];
[alert setMessageText:#"You have placed too many rectangle shapes in your level"];
[alert addButtonWithTitle:#"OK"];
[alert release];
}
}
/* The code here works great but has nothing to do with adding a rect when the button is pressed */
NSRect Rect = NSMakeRect(0.0, 0.0, 7000.0, 3500.0);
int width = Rect.size.width;
int height = Rect.size.height;
int i = 0;
[[NSColor blackColor] set];
NSBezierPath* drawingPath = [NSBezierPath bezierPath];
for (i=0; i<=width; i=i+GRIDSIZE) {
[drawingPath moveToPoint:NSMakePoint(i, 0)];
[drawingPath lineToPoint:NSMakePoint(i, height)];
}
for (i=0; i<=height; i=i+GRIDSIZE) {
[drawingPath moveToPoint:NSMakePoint(0, i)];
[drawingPath lineToPoint:NSMakePoint(width, i)];
}
[drawingPath stroke];
}
Thank you in advance for your help.

Answer 1

It sounds very much like your datasource is nil. A few possibilities:
You forgot to hook it up in Interface Builder
It isn't connected through Interface Builder, but through another controller — but that class (the controller) has a missing connection in Interface Builder
You simply forgot to assign it
Trace forward from where the datasource is supposed to be set to figure out where the chain of custody disappears.