<p>I'm calling a non-.NET dll from my project using P/Invoke, meaning that the .dll must always be present in the .exe's directory. </p>

<p>Is there any way to tell Visual Studio of this dependency, so that it will automatically copy the .dll to the output directory when compiling, and will automatically include the .dll in the setup? Or do I have to do this manually?</p>

You can simply add the .DLL to your project.
Select the
```
Properties
```
pane for that file and set
```
Build Action
```
to
```
Content
```
and
```
Copy to Output Directory
```
to
```
Copy if newer
```
.