{"record":{"id":"6d8556685c2abc84","repo":"dotnet/wpf","slug":"this-feature-is-not-supported","errorCode":null,"errorMessage":"This feature is not supported.","messagePattern":"This feature is not supported\\.","errorType":"exception","errorClass":"NotSupportedException","httpStatus":null,"severity":"error","filePath":"src/Microsoft.DotNet.Wpf/src/WindowsBase/System/IO/Packaging/CompoundFile/DataSpaceManager.cs","lineNumber":1806,"sourceCode":"    {\n        transformHost = host;\n        transformLabel = instanceLabel;\n    }\n\n    /// <summary>\n    /// Whether this transform demands that all instance data of other\n    /// transform above it in the transform stack be transformed too\n    /// </summary>\n    internal bool RequireOtherInstanceData\n    {\n        get\n        {\n            return false;\n        }\n        set\n        {\n            transformHost.CheckDisposedStatus();\n            throw new NotSupportedException(\n                SR.NYIDefault);\n        }\n    }\n\n    /// <summary>\n    /// Whether this transform demands that its own instance data be\n    /// free from other data transformation\n    /// </summary>\n    internal bool RequireInstanceDataUnaltered\n    {\n        get\n        {\n            return false;\n        }\n        set\n        {\n            transformHost.CheckDisposedStatus();\n            throw new NotSupportedException(","sourceCodeStart":1788,"sourceCodeEnd":1824,"githubUrl":"https://github.com/dotnet/wpf/blob/81131a70a4c573cd62748a5c36908fc4d662daa9/src/Microsoft.DotNet.Wpf/src/WindowsBase/System/IO/Packaging/CompoundFile/DataSpaceManager.cs#L1788-L1824","documentation":"NotSupportedException from the DataSpaceManager transform-host setter: this property exists to satisfy the ITransformFeatures interface but the setter is explicitly not implemented (SR.NYIDefault). The feature is recognized by the format but this library never supports setting it. The value is checked for disposal first, then the setter always throws.","triggerScenarios":"Assigning to the corresponding ITransformFeatures property (feature-flag setter for a registered transform) via a DataSpaceManager transform host on an open compound file.","commonSituations":"Developers trying to toggle transform features (e.g. rights-management or compression transform flags) programmatically on OPC compound-file packages.","solutions":["Do not set this property; treat it as read-only metadata produced by the transform infrastructure","Avoid transforms that require this feature flag, or pre-author the file with a tool that writes the flag directly","File/verify support in a newer runtime if the feature is genuinely required"],"exampleFix":"// before\ntransformHost.Features[i].RequiresTransformInstanceData = true; // throws NotSupportedException\n// after\n// Do not set; leave transform feature defaults as written by the format.\nbool requires = transformHost.Features[i].RequiresTransformInstanceData; // read is allowed","handlingStrategy":"try-catch","validationCode":"// Avoid calling setters on transform feature flags; read-only access is safe:\n// var v = feature.SomeFlag; // OK","typeGuard":null,"tryCatchPattern":"try { feature.SomeFlag = value; } catch (NotSupportedException) { /* setter intentionally unimplemented; skip */ }","preventionTips":["Never write to ITransformFeatures flag properties — only read them","Prefer ZipPackage-based OPC packages when transform mutation is needed","Consult the interface docs before assigning to properties in MS.Internal packaging types"],"tags":["wpf","packaging","not-implemented","transform"],"backgroundTag":"method-not-implemented","analyzedSha":"81131a70a4c573cd62748a5c36908fc4d662daa9","analyzedAt":"2026-09-14T10:12:48.479Z","contentChangedAt":"2026-09-14T10:12:48.479Z","schemaVersion":2},"datasetVersion":"2026-09-22T01:17:13.364Z"}