How to use the Windows API with C# Vanara

Vanara is a C# library that allows .NET developers to easily access the functions available in the Windows API.

Accessing the Windows API allows us to perform a wide range of actions that wouldn’t be possible otherwise. But in general, its use is complex and error-prone.

Vanara is designed to facilitate this interop work, providing a safe and easy way, without the need to use unsafe code.

For example, Vanara provides functions to work with the system process list, to handle files and directories, to work with the network, among others. It also provides a series of security classes to work with digital certificates, cryptography, and authentication.

How to use Vanara

The number of existing functions in Vanara is so large that, according to the library’s own documentation, the recommended way to use it is as follows,

For example, if we need the GetComputerName function, we search in the Microsoft documentation and, at the bottom of the page, it indicates that it is part of Kernel32.

Now we go to the Vanara.Kernel32 documentation and verify that the function exists.

We add the corresponding Nuget package,

And now we can use the function in our code.

using static Vanara.PInvoke.Kernel32;

var sbSz = 0;
var sb = new StringBuilder(sbSz);

// Get the computer name and display it in the console
if (Kernel32.GetComputerName(sb, ref sbSz))
{
    Console.WriteLine($"Computer name: {sb}");
}
else
{
    Console.WriteLine($"Error getting the computer name: {Win32Error.GetLastError()}");
}

If, for example, we need the FindWindowA function, we go to the Microsoft documentation and see that it is part of User32.dll.

We add the corresponding Nuget package,

And now we can use the function in our code.

string windowTitle = "My Window"; // The title of the window we want to find

var hWnd = FindWindow(null, windowTitle);
if (hWnd != default)
{
	Console.WriteLine($"The window '{windowTitle}' was found with the handle: {hWnd}");
}
else
{
	Console.WriteLine($"The window '{windowTitle}' was not found.");
}

Obviously, it’s not the easiest library to use. But then again, Interop actions, especially with the Windows API, are never entirely easy.

With Vanara we have almost all the Windows API functions in C# functions. This allows us to do many things that are not possible otherwise, and it’s much easier and safer than using the DLLs directly.