Fix: Fixed OverflowException in UpdateSelectionSize (#16165)

Author: yaira2

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

@@ -183,8 +183,8 @@ public bool IsUncompressedItemSizeVisibile
 			set => SetProperty(ref isUncompressedItemSizeVisibile, value);
 		}
 
-		private long itemSizeBytes;
-		public long ItemSizeBytes
+		private decimal itemSizeBytes;
+		public decimal ItemSizeBytes
 		{
 			get => itemSizeBytes;
 			set => SetProperty(ref itemSizeBytes, value);

src/Files.App/Extensions/StringExtensions.cs

@@ -82,6 +82,7 @@ public static string ConvertSizeAbbreviation(this string value)
 		public static string ToSizeString(this double size) => ByteSize.FromBytes(size).ToSizeString();
 		public static string ToSizeString(this long size) => ByteSize.FromBytes(size).ToSizeString();
 		public static string ToSizeString(this ulong size) => ByteSize.FromBytes(size).ToSizeString();
+		public static string ToSizeString(this decimal size) => ByteSize.FromBytes((double)size).ToSizeString();
 		public static string ToSizeString(this ByteSize size) => size.ToBinaryString().ConvertSizeAbbreviation();
 
 		public static string ToLongSizeString(this long size) => ByteSize.FromBytes(size).ToLongSizeString();

src/Files.App/Views/Layouts/BaseLayoutPage.cs

@@ -702,7 +702,7 @@ public void UpdateSelectionSize()
 			var isSizeKnown = !items.Any(item => string.IsNullOrEmpty(item.FileSize));
 			if (isSizeKnown)
 			{
-				long size = items.Sum(item => item.FileSizeBytes);
+				decimal size = items.Sum(item => item.FileSizeBytes);
 				SelectedItemsPropertiesViewModel.ItemSizeBytes = size;
 				SelectedItemsPropertiesViewModel.ItemSize = size.ToSizeString();
 			}