{"record":{"id":"792828b6d214d841","repo":"dotnet/wpf","slug":"sr-format-sr-propertypathnoownertype-ownername","errorCode":null,"errorMessage":"SR.Format(SR.PropertyPathNoOwnerType, ownerName)","messagePattern":"SR\\.Format\\(SR\\.PropertyPathNoOwnerType, ownerName\\)","errorType":"exception","errorClass":"InvalidOperationException","httpStatus":null,"severity":"error","filePath":"src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/PropertyPath.cs","lineNumber":577,"sourceCode":"                else if (throwOnError)\n                    throw new InvalidOperationException(SR.Format(SR.PathParametersIndexOutOfRange, index, PathParameters.Count));\n                else return null;\n            }\n\n            // handle attached-property syntax:  (TypeName.PropertyName)\n            if (IsPropertyReference(name))\n            {\n                name = name.Substring(1, name.Length-2);\n\n                int lastIndex = name.LastIndexOf('.');\n                if (lastIndex >= 0)\n                {\n                    // attached property - get the owner type\n                    propertyName = name.Substring(lastIndex + 1).Trim();\n                    string ownerName = name.Substring(0, lastIndex).Trim();\n                    ownerType = GetTypeFromName(ownerName, context);\n                    if (ownerType == null && throwOnError)\n                        throw new InvalidOperationException(SR.Format(SR.PropertyPathNoOwnerType, ownerName));\n                }\n                else\n                {\n                    // simple name in parens - just strip the parens\n                    propertyName = name;\n                }\n            }\n\n            if (ownerType != null)\n            {\n                // get an appropriate accessor from the ownerType and propertyName.\n                // We prefer accessors in a certain order, defined below.\n                object accessor;\n\n                // 1. DependencyProperty on the given type.\n                accessor = DependencyProperty.FromName(propertyName, ownerType);\n\n                // 2. PropertyDescriptor from item's custom lookup.","sourceCodeStart":559,"sourceCodeEnd":595,"githubUrl":"https://github.com/dotnet/wpf/blob/81131a70a4c573cd62748a5c36908fc4d662daa9/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/PropertyPath.cs#L559-L595","documentation":"ResolvePropertyName throws this InvalidOperationException when attached-property syntax '(TypeName.PropertyName)' is used but the owner type name cannot be resolved to a System.Type via GetTypeFromName (no matching type found through the ParserContext namespace mappings). Without an owner type the attached property cannot be resolved.","triggerScenarios":"Path string '(MyType.MyAttachedProperty)' where MyType has no xmlns prefix mapping and cannot be resolved; an xmlns prefix that is not registered in the ParserContext.XmlnsDictionary; a misspelled or renamed type name in the path.","commonSituations":"XAML binding paths using attached properties (e.g. '(Grid.Row)') where the namespace prefix is missing from XmlnsDictionary; type moved to another namespace/assembly after a refactor; hand-built ParserContext missing standard WPF xmlns mappings.","solutions":["Fully qualify the type with a registered xmlns prefix, e.g. '(local:MyClass.MyAttachedProperty)', and ensure the prefix is added to ParserContext.XmlnsDictionary","Add the missing namespace mapping to XmlnsDictionary, e.g. ctx.XmlnsDictionary[\"local\"] = \"clr-namespace:MyApp;assembly=MyApp\"","Correct the type-name spelling/namespace in the path string","Use the DependencyProperty object directly (e.g. Grid.RowProperty) via PathParameters instead of name-based resolution"],"exampleFix":"// before\nvar ctx = new ParserContext();\nvar path = new PropertyPath(\"(MyClass.AttachedProp)\", ctx); // type unresolvable\n// after\nctx.XmlnsDictionary[\"local\"] = \"clr-namespace:MyApp;assembly=MyApp\";\nvar path = new PropertyPath(\"(local:MyClass.AttachedProp)\", ctx);","handlingStrategy":"validation","validationCode":"// ensure the prefix resolves before building the path\nbool prefixKnown = parserContext.XmlnsDictionary.Contains(\"local\");\nbool typeExists = AppDomain.CurrentDomain.GetAssemblies()\n    .SelectMany(a => { try { return a.GetTypes(); } catch { return Type.EmptyTypes; } })\n    .Any(t => t.Name == \"MyClass\");","typeGuard":"bool CanResolveType(string name, ParserContext ctx) =>\n    !name.Contains(':') || (ctx.XmlnsDictionary[name.Split(':')[0]] != null);","tryCatchPattern":"try { var path = new PropertyPath(\"(local:MyClass.AttachedProp)\", ctx); }\ncatch (InvalidOperationException ex) when (ex.Message.Contains(\"owner type\")) { /* register xmlns or fix type name */ }","preventionTips":["Always register xmlns prefixes in XmlnsDictionary when building ParserContext in code","Mirror all xmlns declarations from the source XAML into the context","Prefer DependencyProperty fields (e.g. Grid.RowProperty) over name-based attached-property paths"],"tags":["wpf","binding","property-path","attached-property","xaml-namespace"],"backgroundTag":"class-not-found","analyzedSha":"81131a70a4c573cd62748a5c36908fc4d662daa9","analyzedAt":"2026-09-14T10:12:48.479Z","contentChangedAt":"2026-09-14T10:12:48.479Z","schemaVersion":2},"datasetVersion":"2026-09-21T21:30:21.729Z"}