string s = null;

if (null != myObject)
{
    s = myObject.propertyName;
}

string result = obj?.ToString();

string result = obj != null ? obj.ToString() : null;

string s = myObject == null ? null : myObject.PropertyName;

if (value != null)
        {
            return value;
        }
        else
        {
            return otherValue;
        }

return value != null ? value : otherValue;

return value ?? otherValue;