CultureInfo.GetCultures(CultureTypes.AllCultures) returns less items on Blazor WASM .NET 5.0

[ilkayilknur]

Describe the bug

I just found out that CultureInfo.GetCultures(CultureTypes.AllCultures) method returns only 11 items on Blazor WASM .NET 5 RC2. The same method returns more than 300 items on .NET Core 3.1. Is this a known issue?

To Reproduce

Call CultureInfo.GetCultures(CultureTypes.AllCultures) method on Blazor WASM .NET 5 RC2.

Exceptions (if any)

Further technical details

.NET SDK (reflecting any global.json):
Version: 5.0.100-rc.2.20479.15
Commit: da7dfa8840

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19041
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\5.0.100-rc.2.20479.15\

Host (useful for support):
Version: 5.0.0-rc.2.20475.5
Commit: c5a3f49

.NET SDKs installed:
3.1.402 [C:\Program Files\dotnet\sdk]
3.1.403 [C:\Program Files\dotnet\sdk]
5.0.100-rc.2.20479.15 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.0-rc.2.20475.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.0-rc.2.20475.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.7 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.0-rc.2.20475.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

• Microsoft Visual Studio Community 2019 Preview Version 16.8.0 Preview 4.0

[ghost]

Tagging subscribers to this area: @tarekgh, @safern, @krwq
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[mkArtakMSFT]

Thanks for contacting us, @ilkayilknur.
@lewing can you please answer? Thanks!

[EgorBo]

<BlazorWebAssemblyLoadAllGlobalizationData>true</BlazorWebAssemblyLoadAllGlobalizationData> should help here.
I wonder if we should load the full ICU version if we can detect that app uses CultureInfo.GetCultures() api?

[lewing]

@mkArtakMSFT is the BlazorWebAssemblyLoadAllGlobalizationData setting documented anywhere? I found it by reading the code when looking into #43398

[lewing]

@ilkayilknur It is expected. We've started to document the situation at https://docs.microsoft.com/en-us/dotnet/standard/globalization-localization/globalization-icu#icu-on-webassembly but that doesn't include some of the details about how the data is split up and only a fraction of it (based on the browser language) is loaded by default.
If you intend to load other cultures than the automatic subset you can include:

<BlazorWebAssemblyLoadAllGlobalizationData>true</BlazorWebAssemblyLoadAllGlobalizationData>

in your .csproj. That will load a larger subset of cultures that is intended to mirror the cultures that are supported by browsers. We're working to improve the documentation to cover this.

[tarekgh]

@ilkayilknur I am wondering, what is your scenario that you need to call GetCultures? I am seeing some pattern of the usage of calling this method which is used in wrong way.

[lewing]

@pranavkm has added some documentation about the option

[SamMonoRT]

@lewing @pranavkm - is this still an issue for .NET6 or can be closed ?