Question: Basically I have created an app that reads and writes values in text boxes to an XML file. Instead of using all text boxes I want to add in some combo boxes but I am not sure what property is needed for it. 

```
 String ^strMake  = this->txtMake->Text;
             String ^strModel = this->txtModel->Text;
             String ^strName = this->txtName->Text;
             String ^strParentPart = this->txtParentPart->Text;
             String ^strPartID = this->txtPartId->Text;
             String ^strPartType = this->comboBox1->???????????????

```

(The question marks is what I need to fill in)

Answer: 
After a lot of debugging I found that this was actually due to a memory corruption being caused by the QSStrings library which I was using to generate base64 encoded strings. The crashes seemed to happen randomly but only after this library was invoked. When I switched to a different MD5 library, the issue went away. If you are using this library, I would suggest finding a new one to do base64 encoding. I moved to the one found here: <http://www.cocoadev.com/index.pl?BaseSixtyFour>
I think the problem happens because you have something wrong in your view that owns your label (view of your ActiveChallengeViewController).

When you set the font of your label, that invokes the setNeedsDisplay of your parent view and because something is wrong, setNeedsDisplay crashs.

Your line :

```
self.challengeImageView.image = [self.activeChallenge.challenge retrieveImage:self.bruConnection withCallback:imageCallback];

```

Is it a synchronous connection to retrieve the image ?

Maybe the problem happen here when sometimes the image isn't retrieved from your connection and so the image property of your image view is bad.

But i am not sure because setNeedsDisplay doesn't directly invoke the redraw of the view so i don't know if the debugger catches the error just the after setNeedsDisplay call.

Edit :

I think this answer is bad, if image is not ok, the crash must happen when the imageView image property retains the image but i let the answer in the case of it could help you to point to the real problem.