在.net mvc中从Bootstrap 3.7更新到5.0.2会产生错误-System.NullReferenceEx

Question

我卸载了.net MVC应用程序附带的基本引导程序模板，并从NuGetPackage Manager安装了引导程序5.0.2。现在我在运行时遇到了这个问题(构建成功(：

System.NullReferenceException
HResult=0x80004003
Message=Object reference not set to an instance of an object.
Source=WebGrease
StackTrace:
at Microsoft.Ajax.Utilities.JSParser.ParseObjectLiteralProperty(Boolean isBindingPattern)
at Microsoft.Ajax.Utilities.JSParser.ParseObjectLiteral(Boolean isBindingPattern)
at Microsoft.Ajax.Utilities.JSParser.ParseLeftHandSideExpression(Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseUnaryExpression(Boolean& isLeftHandSideExpr, Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseExpressionList(JSToken terminator)
at Microsoft.Ajax.Utilities.JSParser.ParseMemberExpression(AstNode expression, List`1 newContexts)
at Microsoft.Ajax.Utilities.JSParser.ParseLeftHandSideExpression(Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseUnaryExpression(Boolean& isLeftHandSideExpr, Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseExpressionStatement(Boolean fSourceElement)
at Microsoft.Ajax.Utilities.JSParser.ParseStatement(Boolean fSourceElement, Boolean skipImportantComment)
at Microsoft.Ajax.Utilities.JSParser.ParseBlock()
at Microsoft.Ajax.Utilities.JSParser.ParseArrowFunction(AstNode parameters)
at Microsoft.Ajax.Utilities.JSParser.ParseLeftHandSideExpression(Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseUnaryExpression(Boolean& isLeftHandSideExpr, Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseExpressionList(JSToken terminator)
at Microsoft.Ajax.Utilities.JSParser.ParseMemberExpression(AstNode expression, List`1 newContexts)
at Microsoft.Ajax.Utilities.JSParser.ParseLeftHandSideExpression(Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseUnaryExpression(Boolean& isLeftHandSideExpr, Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseExpressionStatement(Boolean fSourceElement)
at Microsoft.Ajax.Utilities.JSParser.ParseStatement(Boolean fSourceElement, Boolean skipImportantComment)
at Microsoft.Ajax.Utilities.JSParser.ParseBlock()
at Microsoft.Ajax.Utilities.JSParser.ParseStatement(Boolean fSourceElement, Boolean skipImportantComment)
at Microsoft.Ajax.Utilities.JSParser.ParseIfStatement()
at Microsoft.Ajax.Utilities.JSParser.ParseStatement(Boolean fSourceElement, Boolean skipImportantComment)
at Microsoft.Ajax.Utilities.JSParser.ParseFunctionBody(Block body)
at Microsoft.Ajax.Utilities.JSParser.ParseFunction(FunctionType functionType, Context fncCtx)
at Microsoft.Ajax.Utilities.JSParser.ParseObjectLiteralProperty(Boolean isBindingPattern)
at Microsoft.Ajax.Utilities.JSParser.ParseObjectLiteral(Boolean isBindingPattern)
at Microsoft.Ajax.Utilities.JSParser.ParseLeftHandSideExpression(Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseUnaryExpression(Boolean& isLeftHandSideExpr, Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseVarDecl(JSToken inToken)
at Microsoft.Ajax.Utilities.JSParser.ParseVariableStatement()
at Microsoft.Ajax.Utilities.JSParser.ParseStatement(Boolean fSourceElement, Boolean skipImportantComment)
at Microsoft.Ajax.Utilities.JSParser.ParseFunctionBody(Block body)
at Microsoft.Ajax.Utilities.JSParser.ParseFunction(FunctionType functionType, Context fncCtx)
at Microsoft.Ajax.Utilities.JSParser.ParseLeftHandSideExpression(Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseUnaryExpression(Boolean& isLeftHandSideExpr, Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseExpression(Boolean single, JSToken inToken)
at Microsoft.Ajax.Utilities.JSParser.ParseLeftHandSideExpression(Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseUnaryExpression(Boolean& isLeftHandSideExpr, Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseExpressionList(JSToken terminator)
at Microsoft.Ajax.Utilities.JSParser.ParseMemberExpression(AstNode expression, List`1 newContexts)
at Microsoft.Ajax.Utilities.JSParser.ParseLeftHandSideExpression(Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseUnaryExpression(Boolean& isLeftHandSideExpr, Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseExpression(Boolean single, JSToken inToken)
at Microsoft.Ajax.Utilities.JSParser.ParseLeftHandSideExpression(Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseUnaryExpression(Boolean& isLeftHandSideExpr, Boolean isMinus)
at Microsoft.Ajax.Utilities.JSParser.ParseExpressionStatement(Boolean fSourceElement)
at Microsoft.Ajax.Utilities.JSParser.ParseStatement(Boolean fSourceElement, Boolean skipImportantComment)
at Microsoft.Ajax.Utilities.JSParser.ParseStatements(Block block)
at Microsoft.Ajax.Utilities.JSParser.InternalParse()
at Microsoft.Ajax.Utilities.JSParser.Parse(DocumentContext sourceContext)
at Microsoft.Ajax.Utilities.Minifier.MinifyJavaScript(String source, CodeSettings codeSettings)
at System.Web.Optimization.JsMinify.Process(BundleContext context, BundleResponse response)
at System.Web.Optimization.Bundle.ApplyTransforms(BundleContext context, String bundleContent, IEnumerable`1 bundleFiles)
at System.Web.Optimization.Bundle.GenerateBundleResponse(BundleContext context)
at System.Web.Optimization.Bundle.GetBundleResponse(BundleContext context)
at System.Web.Optimization.BundleResolver.GetBundleContents(String virtualPath)
at System.Web.Optimization.AssetManager.DeterminePathsToRender(IEnumerable`1 assets)
at System.Web.Optimization.AssetManager.RenderExplicit(String tagFormat, String[] paths)
at System.Web.Optimization.Scripts.RenderFormat(String tagFormat, String[] paths)
at System.Web.Optimization.Scripts.Render(String[] paths)
at ASP._Page_Views_Shared__Layout_cshtml.Execute() in D:C# ProjectscvcvViewsShared_Layout.cshtml:line 39
This exception was originally thrown at this call stack:
[External Code]
ASP._Page_Views_Shared__Layout_cshtml.Execute() in _Layout.cshtml

这是我的_Layout.chtml文件：

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>@ViewBag.Title - My ASP.NET Application</title>
@Styles.Render("~/Content/css")
@Scripts.Render("~/bundles/modernizr")
</head>
<body>
<div class="navbar navbar-inverse navbar-fixed-top">
<div class="container">
<div class="navbar-header">
<button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
@Html.ActionLink("Application name", "Index", "Home", new { area = "" }, new { @class = "navbar-brand" })
</div>
<div class="navbar-collapse collapse">
<ul class="nav navbar-nav">
<li>@Html.ActionLink("Home", "Index", "Home")</li>
<li>@Html.ActionLink("About", "About", "Home")</li>
<li>@Html.ActionLink("Contact", "Contact", "Home")</li>
</ul>
</div>
</div>
</div>
<div class="container body-content">
@RenderBody()
<hr />
<footer>
<p>&copy; @DateTime.Now.Year - My ASP.NET Application</p>
</footer>
</div>
@Scripts.Render("~/bundles/jquery")
@Scripts.Render("~/bundles/bootstrap")
@RenderSection("scripts", required: false)
</body>
</html>

@Scripts.Render("~/bundles/bootstrap")中的错误

这是BundleConfig.cs文件：

using System.Web;
using System.Web.Optimization;
namespace cv
{
public class BundleConfig
{
// For more information on bundling, visit https://go.microsoft.com/fwlink/?LinkId=301862
public static void RegisterBundles(BundleCollection bundles)
{
bundles.Add(new ScriptBundle("~/bundles/jquery").Include(
"~/Scripts/jquery-{version}.js"));
bundles.Add(new ScriptBundle("~/bundles/jqueryval").Include(
"~/Scripts/jquery.validate*"));
// Use the development version of Modernizr to develop with and learn from. Then, when you're
// ready for production, use the build tool at https://modernizr.com to pick only the tests you need.
bundles.Add(new ScriptBundle("~/bundles/modernizr").Include(
"~/Scripts/modernizr-*"));
bundles.Add(new ScriptBundle("~/bundles/bootstrap").Include(
"~/Scripts/bootstrap.js"));
bundles.Add(new StyleBundle("~/Content/css").Include(
"~/Content/bootstrap.css",
"~/Content/site.css"));
}
}
}

Answer 1

我们替换了以下内容：

bundles.Add(new ScriptBundle("~/bundles/mybundle").Include(
"~/Scripts/...",
"~/Scripts/..."));

带有：

bundles.Add(new Bundle("~/bundles/mybundle").Include(
"~/Scripts/...",
"~/Scripts/..."));

Answer 2

Bootstrap版本3、4和5完全不同。引导程序没有向后兼容性。类名都从版本3更改了。

另一个类似的问题Bootstrap 3和Boostrap 4-alpha版本目前向后兼容吗？

根据Tim Corey的说法，你可以在没有兼容性问题的情况下升级到更大版本的Bootstrap中的任何版本。Bootstrap的每一个新的主要版本都是一次彻底的检修。

Tim Corey解释：https://www.youtube.com/watch?v=1ck9LIBxO14

对于那些不想观看完整视频的人，将在09:50 进行解释