<p>The following returns </p>

<blockquote>
  <p>Type of conditional expression cannot be determined because there is no implicit conversion between 'double' and '&lt;null&gt;'</p>
</blockquote>

<pre><code>aNullableDouble = (double.TryParse(aString, out aDouble) ? aDouble : null)
</code></pre>

<hr>

<p>The reason why I can't just use aNullableBool instead of the roundtrip with aDouble is because aNullableDouble is a property of a generated EntityFramework class which cannot be used as an out par.</p>

```
```
aNullableDouble = (double.TryParse(aString, out aDouble)?new Nullable<double>(aDouble):null)
```
```