无法在C＃的控制台应用程序中读取配置文件

Question

I am trying to read two variables from app.config file in my project in Visual Studio 2012. However I get an exception of : "Configuration System failed to initialize". Any ideas what is wrong here?

Here is my app.config file

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <startup>
    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
  </startup>
  <configurationSections>
    <section name ="connectionConfig" type="ConnectionManager.MyConnectionConfigurationSection"
             />
  </configurationSections>
  <connectionConfig  portNumber="7777"/>
  <connectionConfig  hostName="localhost" />
</configuration>

The C# file:

          namespace ConnectionManager
            {
                public class MyConnectionConfigurationSection : System.Configuration.ConfigurationSection
                {
                    [ConfigurationProperty("portNumber")]
                    public string PortNumber
                    {
                        get
                        {
                            return (string)this["portNumber"];
                        }
                    set
                    {
                        this["portNumber"] = value;
                    }
                }

                [ConfigurationProperty("hostName")]
                public string HostName
                {
                    get
                    {
                        return (string)this["hostName"];
                    }
                    set
                    {
                        this["hostName"] = value;
                    }
                }
            }

            public static class ConnectionApplication
            {
                public static MyConnectionConfigurationSection Config { get; internal set; }

                public static void Initialize()
                {
                    try
                    {
                        Config = ConfigurationManager.GetSection("connectionConfig") as MyConnectionConfigurationSection ;
                    }
                    catch (Exception ex)
                    {
                        Console.WriteLine(ex.Message.ToString());
                    }

                }

            }
    class Program
        {
            static string portNumber;
            static string hostName;
            static void Main(string[] args)
            {
                ConnectionApplication.Initialize();

                portNumber=ConnectionApplication.Config.PortNumber;
                Console.WriteLine(portNumber);

                hostName = ConnectionApplication.Config.HostName;
                Console.WriteLine(hostName);

            }
        }
}

It seems that its not being able to initialize only...when i dump the exception, the exception says : Configuration System failed to initialize. Any suggestions what am i doing wrong

Answer 1

Check your code again:

  <configurationSections>
    <section name ="connectionConfig" type="ConnectionManager.MyConnectionConfigurationSection"
             />
  </configurationSections>
  <connectionConfig  portNumber="7777"/>
  <connectionConfig  hostName="localhost" />

• It's <configSections>
• Why do you declare twice your custom section? <connectionConfig portNumber="7777" hostName="localhost" /> is the right way of using your custom section.
• <section name ="connectionConfig" type="ConnectionManager.MyConnectionConfigurationSection" /> on type attribute should provide the full assembly qualified name of the class. That is, if your assembly is called ConnectionManager you should configure ConnectionManager.MyConnectionConfigurationSection, ConnectionManager .

BTW, in my opinion, if you're going to configure 2 simple settings, I wouldn't use a custom configuration section (this is an overkill). Why don't you just use appSettings which is built-in on .NET configuration model?

<appSettings>
     <add key="connectionManager:host" value="localhost" />
     <add key="connectionManager:port" value="7777" />
</appSettings>

And you'll access these parameters this way:

string host ConfigurationManager.AppSettings["connectionManager:host"];
int port = int.Parse(ConfigurationManager.AppSettings["connectionManager:port"]);

Answer 2

Check your Configuration file:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
    <configurationSections>
        <section name ="connectionConfig" type="ConnectionManager.MyConnectionConfigurationSection"/>
    </configurationSections>
    <connectionConfig  portNumber="7777"/>
    <connectionConfig  hostName="localhost" />
</configuration>

The part containing the portnumber and hostname is outside the section your reading in your code.

Try it like this:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
    <configurationSections>
        <section name ="connectionConfig" type="ConnectionManager.MyConnectionConfigurationSection">        
          <connectionConfig  portNumber="7777"/>
          <connectionConfig  hostName="localhost" />
        </section>
    </configurationSections>
</configuration>