Change the way the allow and deny list is handled.

src/Elders.VSE-FormatDocumentOnSave/AllowDenyDocumentFilter.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
+using System.IO;
 using EnvDTE;
 using Microsoft.VisualStudio.Shell;
 
@@ -17,27 +18,37 @@ public class AllowDenyDocumentFilter : IDocumentFilter
         /// </summary>
         public AllowDenyDocumentFilter() { }
 
-        public AllowDenyDocumentFilter(IEnumerable<string> allowedExtensions, IEnumerable<string> deniedExtensions)
+        public bool MatchesList(IEnumerable<string> list, string filePath)
         {
-            ThreadHelper.ThrowIfNotOnUIThread();
+            string fileName = Path.GetFileName(filePath);
+            string extension = Path.GetExtension(filePath);
 
-            IEnumerable<string> bannedExtensions = deniedExtensions
-                .Except(allowedExtensions)
-                .Where(ext => ext.Equals(".*") == false && string.IsNullOrEmpty(ext) == false);
+            foreach (string element in list)
+            { 
+                if(string.IsNullOrEmpty(element))
+                    continue;
+                if (element.Equals(".*"))
+                    return true;
+                if (fileName.EndsWith(element, StringComparison.OrdinalIgnoreCase))
+                    return true;
+                if (extension.EndsWith(element, StringComparison.OrdinalIgnoreCase))
+                    return true;
+            }
 
-            IEnumerable<string> approvedExtensions = allowedExtensions
-                .Except(deniedExtensions)
-                .Where(ext => ext.Equals(".*") == false && string.IsNullOrEmpty(ext) == false);
-
-            bool areAllExtensionsAllowed = allowedExtensions.Where(ext => ext.Equals(".*")).Any();
-            bool areAllExtensionsDenied = deniedExtensions.Where(ext => ext.Equals(".*")).Any();
+            return false;
+        }
+
+        public AllowDenyDocumentFilter(IEnumerable<string> allowedExtensions, IEnumerable<string> deniedExtensions)
+        {
+            ThreadHelper.ThrowIfNotOnUIThread();
 
             isAllowed = doc =>
             {
                 ThreadHelper.ThrowIfNotOnUIThread();
-                return areAllExtensionsAllowed ||
-                approvedExtensions.Any(ext => { ThreadHelper.ThrowIfNotOnUIThread(); return doc.FullName.EndsWith(ext, StringComparison.OrdinalIgnoreCase); }) ||
-                (bannedExtensions.Any(ext => { ThreadHelper.ThrowIfNotOnUIThread(); return doc.FullName.EndsWith(ext, StringComparison.OrdinalIgnoreCase); }) == false && areAllExtensionsDenied == false);
+                if(MatchesList(allowedExtensions, doc.FullName))
+                    if(!MatchesList(deniedExtensions, doc.FullName))
+                        return true;
+                return false;
             };
         }
 

src/Elders.VSE-FormatDocumentOnSave/Configurations/VisualStudioConfiguration.cs

@@ -12,13 +12,13 @@ public class VisualStudioConfiguration : DialogPage, IConfiguration
         public bool IsEnable { get; set; } = true;
 
         [Category("Format Document On Save")]
-        [DisplayName("Allowed extensions")]
-        [Description("Space separated list. For example: [.cs .html .cshtml .vb] Overrides extensions listed in Denied section. When you use [.*] the extensions listed in Denied section will be ignored. Empty value respects all extensions listed in Denied section.")]
+        [DisplayName("Allowed extensions or filenames")]
+        [Description("Space separated list. For example: [.cs .html .cshtml .vb .h .cpp]. The file extension (.cs) or filename (somefile.cs) needs to match an entry in the list to get formatted. The allow list is checked prior to the denie list.")]
         public string Allowed { get; set; } = ".*";
 
         [Category("Format Document On Save")]
-        [DisplayName("Denied extensions")]
-        [Description("Space separated list. For example: [.cs .html .cshtml .vb]")]
+        [DisplayName("Denied extensions or filenames")]
+        [Description("Space separated list. For example: [resource.h]. The file extension (.cs) or filename (somefile.cs) needs to match an entry in the list to NOT get formatted")]
         public string Denied { get; set; } = "";
 
         [Category("Format Document On Save")]

src/Elders.VSE-FormatDocumentOnSave/source.extension.vsixmanifest

@@ -3,7 +3,7 @@
 	<Metadata>
 		<Identity Id="2f4fac85-be4e-4d7a-8c74-93cc4389b427" Version="3.13" Language="en-US" Publisher="Elders" />
 		<DisplayName>Format document on Save</DisplayName>
-		<Description xml:space="preserve">Enables auto formatting of the code when you save a file. Visual Studio supports auto formatting of the code with the CTRL+E,D or CTRL+E,F key shortcuts but with this extension the VS command 'Format Document' is executed on Save.
+		<Description xml:space="preserve">Enables auto formatting of the code when you save a file. Visual Studio supports auto formatting of the code with the CTRL+E,D or CTRL+E,F key shortcuts but with this extension the VS command 'Format Document' is executed on Save. Original by Elders (https://github.com/Elders/VSE-FormatDocumentOnSave). Changed allow deny list handling (filename or extension needs to be in allowed but not in denied) 
 
 You can find the source here: https://github.com/Elders/VSE-FormatDocumentOnSave</Description>
 	</Metadata>