Runtime binding issue using Facebook OAuth

Question

I implemented a login example using Facebook OAuth, but I ran into an issue after login credentials are input.

One of the fields that are being pulled in to the TBInfos text box is causing a null reference due to possibly the user not having a value for one of the fields.

I would usually check for null using something like this, s == null || s == String.Empty;but I'm not sure how to apply it to the below code in question.

My question is, how can I implement a null or empty check for each of the fields pulled into the text box?

The complete error thrown is as follows:

 An exception of type 'Microsoft.CSharp.RuntimeBinder.RuntimeBinderException' occurred in System.Core.dll but was not handled in user code

    Additional information: Cannot perform runtime binding on a null reference

//create instance of FB client
private FacebookClient fbC;

This is the code in question that pulls in the values from Facebook:

public InfoWindow(FacebookClient FBClient)
{
    InitializeComponent();
    fbC = FBClient;
    dynamic me = FBClient.Get("Me");
    TBInfos.Text = "Name : " + me.name.ToString() + "\n\r"
                   + "Gender : " + me.gender.ToString() + "\n\r"
                   + "Link : " + me.link.ToString() + "\n\r"
                   + "Quote : " + me.quotes.ToString() + "\n\r"
                   + "Sports : ";
    foreach (var item in me.sports)
    {
        TBInfos.Text += item.name + " , ";
    }
    TBInfos.Text += "\n\r" + "Favorite Athletes : ";
    foreach (var item in me.favorite_athletes)
    {
        TBInfos.Text += item.name + " , ";
    }
    TBInfos.Text += "\n\r" + "Languages : ";
    foreach (var item in me.languages)
    {
        TBInfos.Text += item.name + " , ";
    }

}

Answer 1

I resolved the above null pointer exception by adding a null check for each of the fields being pulled in.

The following fixed it: (me.gender ?? (object)string.Empty).ToString()

The issue was that for some of the Facebook profiles, one or more of the fields may have been blank/null, which is what caused the exception.