Convert Objective C to Monotouch (Rounded Table Grouped) - xamarin

Question

I have the following Objective C code:
CGFloat cornerRadius = 5.f;
cell.backgroundColor = UIColor.clearColor;
CAShapeLayer *layer = [[CAShapeLayer alloc] init];
CGMutablePathRef pathRef = CGPathCreateMutable();
CGRect bounds = CGRectInset(cell.bounds, 10, 0);
BOOL addLine = NO;
if (indexPath.row == 0 && indexPath.row == [tableView numberOfRowsInSection:indexPath.section]-1) {
CGPathAddRoundedRect(pathRef, nil, bounds, cornerRadius, cornerRadius);
} else if (indexPath.row == 0) {
CGPathMoveToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMaxY(bounds));
CGPathAddArcToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMinY(bounds), CGRectGetMidX(bounds), CGRectGetMinY(bounds), cornerRadius);
CGPathAddArcToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMinY(bounds), CGRectGetMaxX(bounds), CGRectGetMidY(bounds), cornerRadius);
CGPathAddLineToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMaxY(bounds));
addLine = YES;
} else if (indexPath.row == [tableView numberOfRowsInSection:indexPath.section]-1) {
CGPathMoveToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMinY(bounds));
CGPathAddArcToPoint(pathRef, nil, CGRectGetMinX(bounds), CGRectGetMaxY(bounds), CGRectGetMidX(bounds), CGRectGetMaxY(bounds), cornerRadius);
CGPathAddArcToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMaxY(bounds), CGRectGetMaxX(bounds), CGRectGetMidY(bounds), cornerRadius);
CGPathAddLineToPoint(pathRef, nil, CGRectGetMaxX(bounds), CGRectGetMinY(bounds));
} else {
CGPathAddRect(pathRef, nil, bounds);
addLine = YES;
}
layer.path = pathRef;
CFRelease(pathRef);
layer.fillColor = [UIColor colorWithWhite:1.f alpha:0.8f].CGColor;
if (addLine == YES) {
CALayer *lineLayer = [[CALayer alloc] init];
CGFloat lineHeight = (1.f / [UIScreen mainScreen].scale);
lineLayer.frame = CGRectMake(CGRectGetMinX(bounds)+10, bounds.size.height-lineHeight, bounds.size.width-10, lineHeight);
lineLayer.backgroundColor = tableView.separatorColor.CGColor;
[layer addSublayer:lineLayer];
}
UIView *testView = [[UIView alloc] initWithFrame:bounds];
[testView.layer insertSublayer:layer atIndex:0];
testView.backgroundColor = UIColor.clearColor;
cell.backgroundView = testView;
That I translate into C# (Xamarin):
float cornerRadius = 5f;
cell.BackgroundColor = UIColor.Clear;
CAShapeLayer layer = new CAShapeLayer ();
CGPath pathRef = new CGPath();
RectangleF bounds = new RectangleF(cell.Bounds.X,cell.Bounds.Y, 5, 0);
bool addLine = false;
if (indexPath.Row == 0 && indexPath.Row == tableView.NumberOfRowsInSection(indexPath.Section)-1) {
pathRef.AddRoundedRect (bounds, cornerRadius, cornerRadius);
} else if (indexPath.Row == 0) {
pathRef.MoveToPoint (bounds.GetMinX(), bounds.GetMaxY());
pathRef.AddArcToPoint(bounds.GetMinX(),bounds.GetMinY(), bounds.GetMidX(),bounds.GetMinY(),cornerRadius);
pathRef.AddArcToPoint(bounds.GetMaxX(),bounds.GetMinY(), bounds.GetMaxX(),bounds.GetMidY(),cornerRadius);
pathRef.AddLineToPoint(bounds.GetMaxX(),bounds.GetMaxY());
addLine = true;
} else if (indexPath.Row == tableView.NumberOfRowsInSection(indexPath.Section)-1) {
pathRef.MoveToPoint (bounds.GetMinX(), bounds.GetMinY());
pathRef.AddArcToPoint(bounds.GetMinX(),bounds.GetMaxY(), bounds.GetMidX(),bounds.GetMaxY(),cornerRadius);
pathRef.AddArcToPoint(bounds.GetMaxX(),bounds.GetMaxY(), bounds.GetMaxX(),bounds.GetMidY(),cornerRadius);
pathRef.AddLineToPoint(bounds.GetMaxX(),bounds.GetMinY());
} else {
pathRef.AddRect (bounds);
addLine = true;
}
layer.Path = pathRef;
//CFRelease(pathRef);
layer.FillColor = new CGColor (1f, 0.8f);// UIColor.FromWhiteAlpha (1f, 0.8f);
if (addLine) {
CALayer lineLayer = new CALayer ();
float lineHeight = (1f / UIScreen.MainScreen.Scale);
lineLayer.Frame = new RectangleF (bounds.GetMinX () + 10, bounds.Size.Height - lineHeight, bounds.Size.Width - 10, lineHeight);
lineLayer.BackgroundColor = tableView.SeparatorColor.CGColor;
layer.AddSublayer (lineLayer);
}
UIView testView = new UIView (bounds);
testView.Layer.InsertSublayer (layer, 0);
testView.BackgroundColor = UIColor.Clear;
cell.BackgroundView = testView;
But it's now working, I don't get an app crash neither an error when I build.
I want to achieve the following from this question:
iOS 7 TableView like in Settings App on iPad