DevKit breaks autocomplete in Razor components

[EdCharbeneau]

Describe the Issue

When C# DevKit is enabled, auto complete produces extra " characters and interrupts my workflow. When typing = and Razor properties, the editor wraps values in duplicate " characters.

The example shows what the resulting code looks like without manual intervention (backspacing and removing extras):

    <TelerikDropDownList Data="="@Products"
        Width="="400px"
        TextField="="@nameof(ProductDto.ProductName)"
        ValueField="="@nameof(ProductDto.ProductId)"
        @bind-Value="="@SelectedProductId"/>"""""

A video of this can be seen here.

quote-all-the-things.mp4

Steps To Reproduce

Updated Note: The ="=" text occurs if you try to set a parameter without closing the main component tag first.

1. In a Blazor application
2. disabled all extensions
3. Typing works as expected with no extra " characters
4. Enabled C# DevKit and restart the IDE
5. Extra characters appear when typing

Expected Behavior

<TelerikDropDownList Data="@Products"
        Width="400px"
        TextField="@nameof(ProductDto.ProductName)"
        ValueField="@nameof(ProductDto.ProductId)"
        @bind-Value="@SelectedProductId"/>

Environment Information

Version: 1.103.2 (system setup)
Commit: 6f17636121051a53c88d3e605c491d22af2ba755
Date: 2025-08-20T16:45:34.255Z
Electron: 37.2.3
ElectronBuildId: 12035395
Chromium: 138.0.7204.100
Node.js: 22.17.0
V8: 13.8.500258-electron.0
OS: Windows_NT x64 10.0.26100

DevKit:
ms-dotnettools.csdevkit
Version
1.50.33
Last Updated
2025-08-29, 11:41:50

[EdCharbeneau]

Note: The extension appears to ignore these settings, or the bug is happening outside of where applicable to the extension.

    "[razor]": {
  "editor.autoClosingQuotes": "never",
  "editor.autoSurround": "never"
},
"[csharp]": {
  "editor.autoClosingQuotes": "never",
  "editor.autoSurround": "never"
},
    "editor.autoClosingBrackets": "never",
    "editor.autoClosingQuotes": "never",

[claudiaregio]

@EdCharbeneau do you see this issue if you downgrade to the previous version?

[EdCharbeneau]

Yes. I just tried to downgrade C# DevKit and the C# base language extension. The issue is there.

[claudiaregio]

@davidwengier to take a look at this one

[davidwengier]

Looks like dotnet/vscode-csharp#7678

There have been a few attempts at fixing various aspects of that issue, I'll have to go through and make sure they're still correctly working. That fix only applied to Html attributes, need to push it further.

[davidwengier]

@claudiaregio I've put this on the board for pre release 1 for September. Feel free to adjust, or let me know, if that's not correct.

[EdCharbeneau]

More testing around Razor would be amazing! I feel like .razor is the outcast in VSC.

[claudiaregio]

@davidwengier is this a quick fix? Are you able to share rough costing?

[davidwengier]

PR was up 4 hours after my above comment, so pretty quick. Let me know if we should backport anywhere.