#win32 #webview2

macro webview2-com-callback-macros

Macros which generate callback implementations for WebView2 COM APIs

2 releases

0.1.1 Sep 6, 2021
0.1.0 Sep 6, 2021

#5 in #webview2

MIT license

203 lines


Rust bindings for the WebView2 COM APIs

Crates in this repo

The root of this repo defines a virtual workspace in Cargo.toml which includes three crates:

Windows Metadata

The Windows crate requires a Windows Metadata (winmd) file describing the API. The one used in this repo was generated with the webview2-win32md project.

Getting started

Run all the tests from the root of the repo:

> cargo test

Or run the sample app from anywhere in the repo:

> cargo run --example sample

See the README.md in webview2-com for more details about using that crate in your own project.


The webview2-com-sys build.rs script automatically downloads and extracts the NuGet package for the SDK and links against the libraries from that package. If you build on a Windows machine, you probably won't need to do anything special to enable this, but if you are building on a Linux or macOS machine, you need to have mono installed and on your $PATH to execute the nuget.exe CLI tool.

By default this crate uses the WebView2LoaderStatic.lib static library and does not need to redistribute WebView2Loader.dll. However, this doesn't work with the *-pc-windows-gnu targets instead of *-pc-windows-msvc (for example, when cross-compiling). For the gnu targets, it will link against the import lib for WebView2Loader.dll instead, and you will need to place this DLL next to your executable or in your $PATH so it can find the DLL at runtime.

Updating the WebView2 SDK

You can tell the build script to use a different version by updating WEBVIEW2_VERSION in build.rs:

    const WEBVIEW2_VERSION: &str = "1.0.1774.30";

It will also regenerate callback_interfaces.rs if they change in a new version. This file is used in webview2-com, and in particular, the tests in callback.rs verify that all of the interfaces listed in callback_interfaces.rs are implemented. If a new version of the SDK declared additional callback interfaces, you will need to add those interfaces to callback.rs using the #[completed_callback] (for ICoreWebView2...CompletedHandler interfaces) and #[event_callback] (for ICoreWebView2...EventHandler interfaces) macros.

It does not regenerate the winmd file automatically because that would depend on having the dotnet CLI installed. New versions of the SDK should be backwards compatible, but you may want to regenerate the Microsoft.Web.WebView2.Win32.winmd file using webview2-win32md if you need functionality which was added in a new version. You should then copy the file to ./crates/bindings/winmd/Microsoft.Web.WebView2.Win32.winmd, which is where the bindings build script looks for it.


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