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: 
You can use the null coalescing double question marks to test for nulls in a string or other nullable value type:

```
textBox1.Text = s ?? "Is null";

```

The operator '??' asks if the value of 's' is null and if not it returns 's'; if it is null it returns the value on the right of the operator.

More info here:
<https://msdn.microsoft.com/en-us/library/ms173224.aspx>

And also worth noting there's a null-conditional operator ?. and ?[ introduced in C# 6.0 (and VB) in VS2015

```
textBox1.Text = customer?.orders?[0].description ?? "n/a";

```

This returns "n/a" if description is null, or if the order is null, or if the customer is null, else it returns the value of description.

More info here:
<https://msdn.microsoft.com/en-us/library/dn986595.aspx>
For .net 5 (probably also for .net Core 3.1)

Different possibility to write but always the same problem.

```
string wep = test ?? "replace";
Console.WriteLine(wep);

```

result: "replace"

or

```
string test=null;
test ??= "replace";
Console.WriteLine(test);
test="";
test??="replace";
Console.WriteLine(test);

```

* first try: "replace"
* second try: blank

```
string test="";
if(test is null)
    Console.WriteLine("yaouh");
else
    Console.WriteLine("Not yahouu");

```

Result: "Not yahou"