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I have seen this on a newly-generated ASP.NET Core 9 app and in an app I upgraded to .NET 9 from .NET 8.
This is in Views/Shared/_Layout.cshtml:
<script type="importmap">
{
"imports": {
"axios": "/js/axios.min.js",
"axios-retry": "/js/axios-retry.js",
"is-retry-allowed": "/js/is-retry-allowed.js"
}
}
</script>
and it gets stripped out. When I look at the devtools/sources tab in Chrome, it's there for the .NET 8 app, but not for the .NET 9 app.
How do I stop .NET 9 from doing that?
Edit: I found that the ScriptTagHelper class is the culprit.
If I add the following to _ViewImports.cshtml the importmap is not stripped out:
@removeTagHelper Microsoft.AspNetCore.Mvc.TagHelpers.ScriptTagHelper, Microsoft.AspNetCore.Mvc.TagHelpers
I'm guessing I don't want the ScriptTagHelper class permanently disabled (or do I?). Is there a way to tell it "leave my importmap alone"?
206
After checking the source code, you are missing asp-importmap when using importmap.
Source code links:
private const string ImportMapAttributeName = "asp-importmap";
If we are missing asp-importmap attribute, we will get null exception in below code. That's why the script content not render in broswer.
var importMap = ImportMap ?? ViewContext.HttpContext.GetEndpoint()?.Metadata.GetMetadata();
Here is the soultion
@using Microsoft.AspNetCore.Components
@{
var data = new ImportMapDefinition(
new Dictionary<string, string>
{
{ "axios", "/js/axios.min.js" },
{ "axios-retry", "/js/axios-retry.js" },
{ "is-retry-allowed", "/js/is-retry-allowed.js" },
},null,null);
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>@ViewData["Title"] - _79279047_1</title>
<script type="importmap" asp-importmap="@data"></script>
<link rel="stylesheet" href="~/lib/bootstrap/dist/css/bootstrap.min.css" />
<link rel="stylesheet" href="~/css/site.css" asp-append-version="true" />
<link rel="stylesheet" href="~/_79279047_1.styles.css" asp-append-version="true" />
</head>
<body>
<header>
<nav class="navbar navbar-expand-sm navbar-toggleable-sm navbar-light bg-white border-bottom box-shadow mb-3">
<div class="container-fluid">
<a class="navbar-brand" asp-area="" asp-controller="Home" asp-action="Index">_79279047_1</a>
<button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target=".navbar-collapse" aria-controls="navbarSupportedContent"
aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="navbar-collapse collapse d-sm-inline-flex justify-content-between">
<ul class="navbar-nav flex-grow-1">
<li class="nav-item">
<a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Index">Home</a>
</li>
<li class="nav-item">
<a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>
</li>
</ul>
</div>
</div>
</nav>
</header>
<div class="container">
<main role="main" class="pb-3">
@RenderBody()
</main>
</div>
<footer class="border-top footer text-muted">
<div class="container">
© 2024 - _79279047_1 - <a asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>
</div>
</footer>
<script src="~/lib/jquery/dist/jquery.min.js"></script>
<script src="~/lib/bootstrap/dist/js/bootstrap.bundle.min.js"></script>
<script src="~/js/site.js" asp-append-version="true"></script>
@await RenderSectionAsync("Scripts", required: false)
</body>
</html>
Test Result
183
answered Oct 22 '25 03:10
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