Excel Add-In not loading app.config with service reference config information

Question

I\'ve written an app with a service reference to make web services calls to a specific URL and it works great. I want to move this code into an Excel Add-In, but I run into

Answer 1

I have had the same problem recently myself and found that the best solution was contained in:

Change default app.config at runtime

pointing your config file at:

AppDomain.CurrentDomain.BaseDirectory + "AssemblyName.dll.config"

where AssemblyName is the name of your addin assembly

Answer 2

You would need to open it using the ConfigurationManager. You can find your app.config file in the calling assembly path (usually), so you could write a method like this:

public static Configuration LoadLocalConfigurationFile(string fileName)
{
    // fileName is the configuration file you want to open
    var configMap = new ExeConfigurationFileMap 
    { 
        ExeConfigFilename = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, fileName)
    };

    return ConfigurationManager.OpenMappedExeConfiguration(
        configMap, ConfigurationUserLevel.None);
}

Answer 3

As @hexboy noted in his comment, the answer is that ExcelDNA requires the config file to be the same name as the "xll" file but with a ".config" extension. Then ExcelDNA will load the configuration automatically and no further code is required.

Note also that ExcelDNA produces various different files on build. E.g. addin.xll, addin-packed.xll, addin64.xll, addin64-packed.xll where the project assembly is named addin.

In order for a config file to be picked up, it needs to match the file name that is used for the add-in. E.g. addin-packed.xll.config if using addin-packed.xll as the registered Excel add-in.