Fix exception when trying to export project for which no target-framework moniker was detected.

ICSharpCode.Decompiler.Console/IlspyCmdProgram.cs

@@ -135,12 +135,13 @@ Remarks:
 			return 0;
 		}
 
-		DecompilerSettings GetSettings()
+		DecompilerSettings GetSettings(PEFile module)
 		{
 			return new DecompilerSettings(LanguageVersion) {
 				ThrowOnAssemblyResolveErrors = false,
 				RemoveDeadCode = RemoveDeadCode,
-				RemoveDeadStores = RemoveDeadStores
+				RemoveDeadStores = RemoveDeadStores,
+				UseSdkStyleProjectFormat = WholeProjectDecompiler.CanUseSdkStyleProjectFormat(module),
 			};
 		}
 
@@ -151,7 +152,7 @@ Remarks:
 			foreach (var path in ReferencePaths) {
 				resolver.AddSearchDirectory(path);
 			}
-			return new CSharpDecompiler(assemblyFileName, resolver, GetSettings()) {
+			return new CSharpDecompiler(assemblyFileName, resolver, GetSettings(module)) {
 				DebugInfoProvider = TryLoadPDB(module)
 			};
 		}
@@ -188,7 +189,7 @@ Remarks:
 			foreach (var path in ReferencePaths) {
 				resolver.AddSearchDirectory(path);
 			}
-			var decompiler = new WholeProjectDecompiler(GetSettings(), resolver, resolver, TryLoadPDB(module));
+			var decompiler = new WholeProjectDecompiler(GetSettings(module), resolver, resolver, TryLoadPDB(module));
 			decompiler.DecompileProject(module, outputDirectory);
 			return 0;
 		}
@@ -220,7 +221,7 @@ Remarks:
 
 			using (FileStream stream = new FileStream(pdbFileName, FileMode.OpenOrCreate, FileAccess.Write)) {
 				var decompiler = GetDecompiler(assemblyFileName);
-				PortablePdbWriter.WritePdb(module, decompiler, GetSettings(), stream);
+				PortablePdbWriter.WritePdb(module, decompiler, GetSettings(module), stream);
 			}
 
 			return 0;

ICSharpCode.Decompiler/CSharp/ProjectDecompiler/WholeProjectDecompiler.cs

@@ -625,6 +625,11 @@ namespace ICSharpCode.Decompiler.CSharp.ProjectDecompiler
 					return false;
 			}
 		}
+
+		public static bool CanUseSdkStyleProjectFormat(PEFile module)
+		{
+			return TargetServices.DetectTargetFramework(module).Moniker != null;
+		}
 	}
 
 	public readonly struct DecompilationProgress

ILSpy/Languages/CSharpLanguage.cs

@@ -393,6 +393,10 @@ namespace ICSharpCode.ILSpy
 			}
 			if (options.FullDecompilation && options.SaveAsProjectDirectory != null)
 			{
+				if (!WholeProjectDecompiler.CanUseSdkStyleProjectFormat(module))
+				{
+					options.DecompilerSettings.UseSdkStyleProjectFormat = false;
+				}
 				var decompiler = new ILSpyWholeProjectDecompiler(assembly, options);
 				return decompiler.DecompileProject(module, options.SaveAsProjectDirectory, new TextOutputWriter(output), options.CancellationToken);
 			}

ILSpy/Properties/Resources.Designer.cs

@@ -522,6 +522,15 @@ namespace ICSharpCode.ILSpy.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Could not use SDK-style project format, because no compatible target-framework moniker was found..
+        /// </summary>
+        public static string CouldNotUseSdkStyleProjectFormat {
+            get {
+                return ResourceManager.GetString("CouldNotUseSdkStyleProjectFormat", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Create.
         /// </summary>

ILSpy/Properties/Resources.resx

@@ -201,6 +201,9 @@ Are you sure you want to continue?</value>
   <data name="CopyName" xml:space="preserve">
     <value>Copy FQ Name</value>
   </data>
+  <data name="CouldNotUseSdkStyleProjectFormat" xml:space="preserve">
+    <value>Could not use SDK-style project format, because no compatible target-framework moniker was found.</value>
+  </data>
   <data name="Create" xml:space="preserve">
     <value>Create</value>
   </data>

ILSpy/TextView/DecompilerTextView.cs

@@ -1075,6 +1075,7 @@ namespace ICSharpCode.ILSpy.TextView
 				delegate {
 					try
 					{
+						bool originalProjectFormatSetting = context.Options.DecompilerSettings.UseSdkStyleProjectFormat;
 						context.Options.EscapeInvalidIdentifiers = true;
 						Stopwatch stopwatch = new Stopwatch();
 						stopwatch.Start();
@@ -1101,11 +1102,16 @@ namespace ICSharpCode.ILSpy.TextView
 						if (context.Options.SaveAsProjectDirectory != null)
 						{
 							output.WriteLine();
-							if (context.Options.DecompilerSettings.UseSdkStyleProjectFormat)
+							bool useSdkStyleProjectFormat = context.Options.DecompilerSettings.UseSdkStyleProjectFormat;
+							if (useSdkStyleProjectFormat)
 								output.WriteLine(Properties.Resources.ProjectExportFormatSDKHint);
 							else
 								output.WriteLine(Properties.Resources.ProjectExportFormatNonSDKHint);
 							output.WriteLine(Properties.Resources.ProjectExportFormatChangeSettingHint);
+							if (originalProjectFormatSetting != useSdkStyleProjectFormat)
+							{
+								output.WriteLine(Properties.Resources.CouldNotUseSdkStyleProjectFormat);
+							}
 						}
 						output.WriteLine();
 						output.AddButton(null, Properties.Resources.OpenExplorer, delegate { Process.Start("explorer", "/select,\"" + fileName + "\""); });