Building an regular expression that will reject an input string which contain spaces.

I have a following expression, but its not working as well; 

```
^[a-zA-Z0-9!@#*()+{}[\\];:,|\/\\\\_\S-]+$

```

**Valid case**

```
String123/test //string without space

```

**Invalid case**

```
String123/ test // contains space in between string 

String 123/test // contains space in between string 

 String123/test  // contains leading\trailing space

```

i.e; I have to white list strings which does not contain any spaces.