An unhandled exception of type 'System.Configuration.ConfigurationErrorsException' occurred in System.Configuration.dll

Question

I was trying to create user secrets in application console in c# in last days but I wasn't able to generate the file secret .

I ended up followed this tutoriel and finally was able to create secret.xml . But when I tried to read data from the secret.xml file, it gave me this error :

Thrown exception: 'System.Configuration.ConfigurationErrorsException' in System.Configuration.dll
An unhandled exception of type 'System.Configuration.ConfigurationErrorsException' occurred in System.Configuration.dll
An error occurred while loading a configuration file: Unable to load the file or assembly 'Microsoft.Configuration.ConfigurationBuilders.UserSecrets, Version = 1.0.0.0, Culture = neutral' or one of its dependencies. The specified file can not be found.

At the beginning I was able to read the password data from the config file , but when I tried to read it from secret file it seemsnot woriking .

Solution tried : -removed the reference to UserSecrets then added it again using Nuget .

Here is my code : click here

App.config :

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <configSections>
        <section name="configBuilders" type="System.Configuration.ConfigurationBuildersSection, System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" restartOnExternalChanges="false" requirePermission="false"/>
    </configSections>
    <configBuilders>
        <builders>
          <add name="Secrets" userSecretsFile="c:\\secrets\\secret.xml" type="Microsoft.Configuration.ConfigurationBuilders.UserSecretsConfigBuilder, Microsoft.Configuration.ConfigurationBuilders.UserSecrets, Version=1.0.0.0, Culture=neutral"/>
        </builders>
      </configBuilders>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1"/>
    </startup>
  <appSettings configBuilders="Secrets">
    <add key="password" value="This is a password placeholder"/>
  </appSettings>
</configuration>

Program.cs :

static void Main(string[] args)
        {
            var password = ConfigurationManager.AppSettings["password"];
            Console.WriteLine($"Password is {password}");
        }

Answer 1

Based on my test, I find the solution. You can try change the current .net framework

version to 4.7.1 or later.

Click properties-> choose target framework-> choose .net Framework 4.7.2

like the following:

Then, you can refer to the app.config I test.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <configSections>
        <section name="configBuilders" type="System.Configuration.ConfigurationBuildersSection, System.Configuration, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" restartOnExternalChanges="false" requirePermission="false"/>
    </configSections>
    <configBuilders>
        <builders>
        <add name="Secrets" userSecretsFile="D:\\secrets.xml" type="Microsoft.Configuration.ConfigurationBuilders.UserSecretsConfigBuilder, Microsoft.Configuration.ConfigurationBuilders.UserSecrets, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/></builders>
    </configBuilders>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2"/>
    </startup>
  <appSettings configBuilders="Secrets">
    <add key="password" value="This is a password placeholder"/>
  </appSettings>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Microsoft.Configuration.ConfigurationBuilders.Base" publicKeyToken="31bf3856ad364e35" culture="neutral"/>
        <bindingRedirect oldVersion="0.0.0.0-2.0.0.0" newVersion="2.0.0.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

You can know .net framework has been changed to v4.7.2.

Finally, I can get the correct result from the console app.