通过global.asax从外部类获取web.config请求

Question

My web-application uses an external class library for certain procedures that I use in many places. One of the things I'd like to add to my library is this configurator class to allow me to encrypt parts of my web.config file.

Now, I am calling the class from global.asax , it compiles, and intellisense doesn't have any issues, but am getting this error upon execution of the web-application:

Request is not available in this context

How do I fix this?

public class configurator {
private Configuration _webconfig;
public const string DPAPI = "DataProtectionConfigurationProvider";

public Configuration webconfig {
    get { return _webconfig; } 
    set { _webconfig = webconfig; } 
}

public configurator() {
    webconfig = WebConfigurationManager.OpenWebConfiguration(HttpContext.Current.Request.ApplicationPath);
}

public void ProtectSection(string sectionName, string provider = DPAPI) {
    ConfigurationSection section = webconfig.GetSection(sectionName);

    if (section != null && !section.SectionInformation.IsProtected) {
        section.SectionInformation.ProtectSection(provider);
        webconfig.Save();
    }
}

public void EncryptConnString(string protectionMode) {
    ConfigurationSection section = webconfig.GetSection("connectionStrings");
    section.SectionInformation.ProtectSection(protectionMode);
    webconfig.Save();
}

public void DecryptConnString() {
    ConfigurationSection section = webconfig.GetSection("connectionStrings");
    section.SectionInformation.UnprotectSection();
    webconfig.Save();
}
}

The class is being called first thing in the global.asax (sorry for the mix; I prefer c#, but started the other project in vb before I started with c#!) :

<%@ Application Language="VB" %>
<script runat="server">
Sub Application_Start(ByVal sender As Object, ByVal e As EventArgs)
    ' Code that runs on application startup - this will encrypt the web.config
    Dim thisconfigurator As mydll.configurator = New orsus.configurator()
    If ConfigurationManager.AppSettings("con") = "production" Then
        thisconfigurator.ProtectSection("AppSettings")
        thisconfigurator.ProtectSection("connectionStrings")
        thisconfigurator.ProtectSection("system.net/mailSettings/smtp")
    End If
End Sub
</script>

Answer 1

David Hoerster was right, Request hasn't been initialized yet, so it will error out. If you only need to access the root config, this works:

webconfig = WebConfigurationManager.OpenWebConfiguration("~");