public ProgressChangedEventArgs(double value, string message)
 {
     if (value > 1.0 || value < 0.0)
     {
         throw new ArgumentOutOfRangeException("value", value, "0 과 1사이의 값을 사용해야 합니다.");
     }
     this.state   = ProgressChangeState.Changed;
     this.value   = value;
     this.message = message;
 }
 public ProgressChangedEventArgs(bool isFailed, string message)
 {
     this.state   = isFailed ? ProgressChangeState.Failed : ProgressChangeState.Completed;
     this.value   = isFailed ? double.MinValue : 1.0;
     this.message = message;
 }