Skip to main content

Recurring issues in Visual Studio projects

Common issues and solutions to errors I come across in Visual Studio on a semi-regular basis:

"Could not find a part of the path … bin\roslyn\csc.exe"
Run this in Package Manager Console:
Update-Package Microsoft.CodeDom.Providers.DotNetCompilerPlatform -r

"Creation of the virtual directory http://localhost:12345/ failed with the error: Cannot create the Web site"
Update .csproj file and set the following:
In the <VisualStudio> element, set the following:

"Could not load file or assembly [assembly name] or one of its dependencies. The located assembly's manifest definition does not match the assembly reference"
If it's a nuget package, check version of the assembly in packages.config, web.config and "References" section in solution explorer, one of them is probably wrong. Try reinstalling or updating the nuget package.

"Creation of the virtual directory [site url] failed with the error : Unable to access the IIS metabase"
Restart Visual Studio as Administrator

"HTTP Error 500.19 - Internal Server Error" in projects that use ASP.NET core and have a <aspNetCore> item in the web.config
Add "Development time IIS support" from in the Visual Studio installer, in "ASP.NET and Web Development" optional features section.

When trying to process JSON data from an API that uses ASP.NET, you receive a "Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: <. Path '', line 0, position 0."
Newtonsoft is expecting to process JSON and getting a response starting with < instead (i.e. it's XML). The API you're calling has probably failed and is throwing back an ASP.NET YSOD page containing HTML. See if you can hit the API directly some other way and check the error message. In my case the server was missing some IIS features and installing them fixed the problem.

"Can't create the virtual directory http://customdomain.local failed with the error: Cannot create the Web site"
Can't run .NET Core projects:
Install at least .NET Core SDK 2.2


Popular posts from this blog

Using WiX to create an event source during install of a .NET framework project

Edit: so I guess I wasn't the only one confused with this stuff, as it's been my most popular post by far!  If I've helped you out or saved you some time, please let me know in the comments :)

In order for this to work, you have to add references to WixUtilExtension and WixNetFxExtension to your WiX project.  Once that's done, add this inside a <Component> element:

<Util:EventSourcexmlns:Util=""Name="EVENTSOURCEGOESHERE"Log="Application"EventMessageFile="[NETFRAMEWORK40FULLINSTALLROOTDIR]EventLogMessages.dll" />
Obviously replace EVENTSOURCEGOESHERE with your event source name.  NETFRAMEWORK40FULLINSTALLROOTDIR is a property set by the WixNetFxExtension which stores the path to the .NET framework v4 directory, but you can replace this with the corresponding property for the directory containing the relevant EventLogMessages.dll file.  So if you're using the .NET framewo…

Using Log4Net to use both event log and a rolling log file

Here's the config section, note that the applicationNameproperty in the EventLogAppender needs to be the same as the event source in the windows event log that you want to log to.  If the event source doesn't exist, that appender won't work.  In this particular project I create that during install using WiX (which is covered in another post)

    <appendername="RollingLogFileAppender"type="log4net.Appender.RollingFileAppender">      <filevalue="log.txt" />      <datePatternvalue="dd-MM-yyyy" />      <appendToFilevalue="true" />      <locationinfovalue="false" />      <rollingStylevalue="Size" />      <maximumFileSizevalue="1MB" />      <maxSizeRollBackupsvalue="10" />      <staticLogFileNamevalue="true" />      <layouttype="log4net.Layout.PatternLayout">        <conv…

"A section using 'configSource' may contain no other attributes or elements" error after installing Application Insights

After installing the Application Insights nuget package to an Umbraco solution, you'll get this error:

A section using 'configSource' may contain no other attributes or elements

<ExamineLuceneIndexSets configSource="config\ExamineIndex.config" />
     <log4net configSource="config\log4net.config">
             <level value="ALL" />
             <appender-ref ref="aiAppender" />
Source File: \project\web.config

This happens because part of the Application Insights installation process adds a <log4net> section to web.config.  Which would make sense, except Umbraco already has a <log4net> section in /config/log4net.config.  So as you can imagine, the solution is to manually move everything its added into that file. Unfortunately you can't just copy/paste the whole lot, but it's not particularly complicated:

Move <appender-ref ref="aiAppender" /> into the lo…