Code Quality: Replaced DllImport calls with CsWin32 generations for DPI calculation operations (#17118)

Author: Lamparter

src/Files.App.CsWin32/NativeMethods.txt

@@ -97,7 +97,6 @@ SendMessage
 IsWindowVisible
 COPYDATASTRUCT
 WINDOW_LONG_PTR_INDEX
-GetDpiForWindow
 CallWindowProc
 MINMAXINFO
 SUBCLASSPROC

src/Files.App/Data/Models/AppModel.cs

@@ -4,6 +4,8 @@
 using Microsoft.UI.Xaml.Controls;
 using System.Runtime.InteropServices;
 using Windows.ApplicationModel.DataTransfer;
+using Windows.Win32;
+using Windows.Win32.Foundation;
 
 namespace Files.App.Data.Models
 {
@@ -127,9 +129,8 @@ public string PCloudDrivePath
 
 		/// <summary>
 		/// Gets or sets a value indicating the AppWindow DPI.
-		/// TODO update value if the DPI changes
 		/// </summary>
-		private float _AppWindowDPI = Win32PInvoke.GetDpiForWindow(MainWindow.Instance.WindowHandle) / 96f;
+		private float _AppWindowDPI = PInvoke.GetDpiForWindow((HWND)MainWindow.Instance.WindowHandle) / 96f;
 		public float AppWindowDPI
 		{
 			get => _AppWindowDPI;

src/Files.App/Helpers/Win32/Win32PInvoke.Methods.cs

@@ -76,11 +76,6 @@ public static extern bool SetEvent(
 			IntPtr hEvent
 		);
 
-		[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
-		public static extern int GetDpiForWindow(
-			IntPtr hwnd
-		);
-
 		[DllImport("ole32.dll")]
 		public static extern uint CoWaitForMultipleObjects(
 			uint dwFlags,