Calling base constructor in c#

class MyExceptionClass : Exception
{
     public MyExceptionClass(string message, string extraInfo)
     {
         //This is where it's all falling apart
         base(message);
     }
}

public class MyExceptionClass : Exception
{
    public MyExceptionClass(string message, string extrainfo) : base(message)
    {
        //other stuff here
    }
}

class MyExceptionClass : Exception
    {
         public MyExceptionClass(string message, string extraInfo) :
         base(ModifyMessage(message, extraInfo))
         {
         }

         private string ModifyMessage(string message, string extraInfo)
         {
             Trace.WriteLine("message was " + message);
             return message.ToLowerInvariant() + Environment.NewLine + extraInfo;
         }
    }

// Constructor 1
public MyExceptionClass(string message, string extraInfo) :
    this(17)  //  calls constructor 2
{
    // ...
}

// Constructor 2
public MyExceptionClass(int foo)
{
    // ...
}

public class MyExceptionClass : Exception
{
    public MyExceptionClass(string message,
      Exception innerException): base(message, innerException)
    {
        //other stuff here
    }
}