What′s New in dotPeek

The 2025.1 release brings several improvements to the decompiler, enhancing support for the latest C# features and improving code readability. Here’s what’s new:

• Support for required members.
• Added support for the new System.Threading.Lock type introduced in C# 13.
• Support for ref fields and scoped parameter modifiers.
• Support for the allows ref struct generic anti-constraint.
• Pattern-based using for ref struct types.
• Support for string interpolation.
• Certain integer constants in decompiled code now include commented hexadecimal representations for better readability.
• Support for file-scoped namespaces.

The IL Viewer tool window now provides IL code for assembly manifest, including:

• Assembly and module info such as name, custom attributes, etc.
• Referenced assemblies and modules.
• Forwarded types.
• A list of files and resources.

This IL code is shown when the caret in the text editor is on an assembly or module attribute or somewhere inside an <AssemblyName>.cs file for external assemblies.

• PDB with SrcSrv and SourceLink: The decompiler now supports navigating to sources from PDB files containing both SrcSrv and SourceLink.
• Preprocessor directives: The decompiler now correctly recognizes preprocessor directives (like NET6_0_OR_GREATER) from the target framework or Portable PDB of the associated assembly, ensuring accurate code representation.
• Open in Browser action: You can now navigate to the source code in the repository for types or to a repository for NuGet packages or assemblies.

The 2024.1 update introduces the new Assembly Diff tool window to dotPeek. There are a couple of changes that come with it:

• The ability to compare assemblies, NuGet packages, folders, and .zip archives has been moved from the Assembly Explorer to the Assembly Diff tool window.
• The Diff mode selector and the Compare and Diff Options buttons have been relocated to the Actions bar of the Assembly Diff tool window.

dotPeek now supports the WebCIL packaging format for WebAssemblies. The support covers:

• Decompilation for WebCIL.
• The ability to view .wasm files in the Assembly Explorer.
• Metadata subtrees for WASM nodes in the Assembly Explorer, including WASM and WebCIL headers.

dotPeek 2023.3 is able to compare NuGet packages, folders, and .zip files.

The ability to compare assemblies now has more comparison options. You can choose between several diff modes (Show all, Show only differences, Show only signature differences, Show only public API differences). Additionally, you can specify if you’d like the diff to ignore member/attribute order differences, as well as differences in nullable reference types’ annotations.

• When exploring NuGet packages in the Assembly Explorer, you’ll now be able to see all files and folders contained inside those NuGet packages.
• Win32 resource nodes, including their size and type (if these can be determined), can now be viewed in the node presentation tree and the Properties pane.

• The ability to decode Win32 string-table resources has now been introduced.
• dotPeek now displays the sizes of open files inside the Properties pane for an assembly/non-assembly, files inside bundles, archives, NuGet packages, compared assemblies, and Win32 resources.
• Assembly authenticode signature validation is now available.
• Explicit #nullable disable directives are shown in decompiled sources.

dotPeek 2023.2 provides a way to compare two assemblies in detail. This feature is especially useful when scrutinizing the differences between two versions of a specific assembly and searching for potential vulnerabilities that may have been introduced in a newer version.

Click here for more information.

The 2023.1 version of dotPeek contains the following improvements for the IL Viewer tool window:

• Local variable names will now be used for both low-level and high-level C# code and variable tuple element names for high-level C# code as in the original source.
• Commented tuple element names will be rendered from the PDB/decompiler for local variable declarations in intermediate language (IL) code.
• Synchronization has been improved for field and property initializers, statements inside iterators, async methods, lambdas, local functions, and local functions and nested local function declarations for high-level C#.

dotPeek 2022.3 comes with support for:

• static abstract and static virtual members in interfaces.
• generic attributes.
• user-defined checked operators.
• unsigned right shift operator.

There is now an option to view decompiled high-level and low-level C# code in the IL Viewer tool window. The decompiled code is still synced to the source code in the code editor.

• The way ReadyToRun (R2R) and NGen assemblies are presented in the Assembly Explorer has been improved. A small processor symbol icon and ngen or R2R labels are now displayed next to each assembly's name.
• The Metadata tree has the ReadyToRun header.
• The Properties window has the ReadyToRun section.

We introduced the ability to show files in a single Preview tab, as you are used to in Visual Studio. It helps when you are looking for something specific and don't want to keep these files open as separate tabs.

If you want to keep the file in a separate tab, click the Keep open icon on the Preview tab. To disable the Preview tab, go to Tools | Options | Tabs and select Allow new files to be opened in the preview tab.

We moved the Quick Find feature from a separate tool window to the text editor tab. Now, when you call Quick Find (Ctrl+F) for a file, the Quick Find pane appears inside the text editor tab for the file.

We also added the F3 and Shift+F3 shortcuts, which allow you to quickly navigate to the next or previous occurrence when you are looking for something using the Quick Find pane.

dotPeek now shows XML doc comments for platform assemblies, including assemblies whose names differ from the names of the XML documentation files, for example, System.Private.CoreLib. The path to the XML documentation is now displayed in the decompiled file’s header.

dotPeek provides initial support for record and record struct types. Support for the with expression for records, record structs, and structs is also available.

As for other C# features included in this release, the decompiler now supports asynchronous dispose (await using).

We’re continuing to improve our support for reading and decompiling single-file apps:

• You can see the content of bundled .json files – for example, the .runtimeconfig.json file.
• You can view a list of all embedded files along with some technical information about the single-file app (header format version and ID) by clicking on the root node in the Assembly Explorer.
• You can extract all the files to a folder (using the Extract Bundle Content to Folder action from the context menu) or one particular file from the bundle as an external file (using the Extract to File action in the context menu).

Now dotPeek can decompile single-file apps. It also lets you browse through bundled assemblies inside a single-file app just like you are used to doing. It supports single-file formats for the .NET Core 3.1, .NET 5, and the upcoming .NET 6 SDKs.

When working with several tabs at once, you can now pin them. Additionally, the color of a tab indicates the type of code you will see – green represents a metadata view and brown stands for sources from symbol files. The options to pin tabs and to color code them can be disabled in Tools | Options | Environment | Tabs.

We’ve updated the formatter for decompiled code with a set of options to control how the code is presented. You can now set indent style and size, select whether the open brace should be placed on a new line, and if you’d prefer to use expression-bodied members. You can find them in Tools | Options | Decompiler | Code style and formatting.