.NET Exception Handling Application Configuration File

Question

I apologize as this question is somewhat basic; however, after a great deal of searching, I have not found a suitable answer. I am building a windows forms application and need to reference an app.config file for the location to a data file. Before calling

XElement xml = XElement.Load(ConfigurationManager.AppSettings["EntityData"].ToString());

I want to ensure that the app.config file exists. I have tried multiple methods but it seems that it is a lot more work then it should be. For example I have been trying to use the following code to determine the path for the file

        Uri uri = new Uri(System.Reflection.Assembly.GetExecutingAssembly().CodeBase);
        string fullConfigurationFilename = System.IO.Path.Combine(System.IO.Path.GetDirectoryName(uri.AbsolutePath), configurationFilename);

but I run into issues with spaces in the path. Is there a better way to check for the existence of the app.config, do I even need to check?

Thank you

Answer 1

System.Configuration should do all of this work for you. There shouldn't be a need to manually load a config file.

Answer 2

I don't think you need to verify that the config file exists. The following code should work without exceptions:

string temp = ConfigurationManager.AppSettings["EntityData"];
if (temp != null)
{
    XElement xml = XElement.Load(temp);
}

Note that AppSettings will return a string if the key is found, so you don't need to call ToString to convert it. If the key does not exist, you should instead get a null reference that you can test for.