Question: I am wondering if there is a special method/trick to check if a `String` object is null. I know about the [`String.IsNullOrEmpty`](http://msdn.microsoft.com/en-us/library/system.string.isnullorempty.aspx) method but I want to differentiate a `null` String from an empty String (=`""`).

Should I simply use:

```
if (s == null) {
    // blah blah...
}

```

...or is there another way?

Answer: 
If you are using `C# 7.0` or above you can use `is null`:

```
if (s is null) {
    // blah blah...
}

```

Also, note that when working with strings you might consider also using `IsNullOrWhiteSpace` that will also validate that the string doesn't contain only spaces.
You can check with null or Number.

First, add a reference to `Microsoft.VisualBasic` in your application.

Then, use the following code:

```
bool b = Microsoft.VisualBasic.Information.IsNumeric("null");
bool c = Microsoft.VisualBasic.Information.IsNumeric("abc");

```

In the above, `b` and `c` should both be `false`.