Question

i am first time using any DI framework called unity app block. i am getting error. the error is :-

The type name or alias ILogger could not be resolved. Please check your configuration file and verify this type name.

i was trying inject dependency from out side into my main proj. suppose i want to save data to anywhere by dependency. say suppose i want to save data to file or console, database etc.

here i am telling you how i develop my app for incorporating Unity.

first i create a class library project called “Ilogger” it has only one interface. full code of this interface

namespace Ilogger
{
    public interface ILog
    {
        void Write(string msg);
    }
}

secondly i create a class library project called “ConsoleWriter” it has only one class which inherit Ilogger interface.so i just add the reference of Ilogger project into ConsoleWriter proj. full code of this ConsoleWriter

namespace ConsoleWriter
{
    public class ConsoleWriter : Ilogger.ILog
    {
        #region ILog Members

        public void Write(string msg)
        {
            Console.WriteLine(msg);
            Console.ReadLine();
        }

        #endregion
    }
}

3rd step i create a class library project called “FileWriter
” it has only one class which inherit Ilogger interface.so i just add the reference of Ilogger project into FileWriter proj. full code of this FileWriter

namespace FileWriter
{
    public class FileWriter : Ilogger.ILog
    {
        #region IWriter Members

        public void Write(string msg)
        {
            using (StreamWriter streamWriter = new StreamWriter("c:\\TestUnity.txt", true))
            {
                streamWriter.WriteLine(msg);
            }
        }
        #endregion
    }
}

next i create my win apps from where i inject dependecy at runtime. in this project i add some dll reference of unity block and those are.

Microsoft.Practices.Unity
Microsoft.Practices.Unity.Configuration
system.configuration

i add one app.config file and it has entry like

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
        <section name="unity" type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection, Microsoft.Practices.Unity.Configuration"/>
    </configSections>

    <unity xmlns="http://schemas.microsoft.com/practices/2010/unity">
        <alias type="ILogger.ILog, ILogger" alias="ILogger" />
        <namespace name="ILogger.ILog"/>

        <container>
            <register mapTo="FileWriter.FileWriter, FileWriter" name="MyFileWriter" type="ILogger"/>
            <register mapTo="ConsoleWriter.ConsoleWriter, ConsoleWriter" name="MyConsoleWriter" type="ILogger"/>
        </container>
    </unity>

</configuration>

here is the main code from where error is thrown

string strCountryCode = “USA”;

    IDictionary<string, string> loggers = new Dictionary<string, string>();
    loggers.Add("USA", "MyFileWriter");
    loggers.Add("GBR", "MyConsoleWriter");

    IUnityContainer container = new UnityContainer();
    UnityConfigurationSection section = (UnityConfigurationSection)System.Configuration.ConfigurationManager.GetSection("unity");
    //container.LoadConfiguration();
    section.Containers.Default.Configure(container);

    Ilogger.ILog logger = container.Resolve<Ilogger.ILog>(loggers[strCountryCode]);
    logger.Write("Hello World");

this line giving error section.Containers.Default.Configure(container);

i am using DI framework unity first time so i am not being able to catch what mistake i made. so please anyone help me to get the error and tell me how to fix it.

thanks

Answer 1

there may be several issues;

• in the entry point of application, where you are trying to read unity configuration, you need to add the assembly which contains ILog interface; the assembly may be missing.

• you need to add aliases using full paths; the full path needs to include the assembly name.

• in order to observe exact problem, instead of using a configuration file, try to make registrations in the code.