gitissue-#3382 missing using directive (#1961)

Author: Karl-Bridge-Microsoft

hub/apps/winui/winui3/desktop-winui3-app-with-basic-interop.md

@@ -96,7 +96,8 @@ The following code shows the MainWindow.xaml file from the initial template app,
 
    :::code language="xaml" source="samples/WinUI-3-basic-win32-interop/WinUI-3-basic-win32-interop/MainWindow.xaml" range="10-19":::
 
-1. In the MainWindow.xaml.cs code-behind file, we replace the `MyButton_Click` event handler with the following code.
+1. In the MainWindow.xaml.cs code-behind file, add the `using static PInvoke.User32;` directive.
+1. We then replace the `MyButton_Click` event handler with the following code.
 
    Here, we get a reference to the current process by calling [GetCurrentProcess](/dotnet/api/system.diagnostics.process.getcurrentprocess). We then iterate through the collection of [Modules](/dotnet/api/system.diagnostics.process.modules) and append the filename of each [ProcessModule](/dotnet/api/system.diagnostics.processmodule) to our display string.