Windows Mobile 3.5でファイルを圧縮する方法は？

DotNetZipのIonic.Zip.dllを使用してファイルを圧縮する方法を作成しようとしています。Windows Mobile 3.5でファイルを圧縮する方法は？

圧縮のためのコード：

using Ionic.Zip; 
public string Compress(string[] Paths, string SaveFileName, string Password, string CompressionType) 
    { 
     try 
     { 
      using (ZipFile zip = new ZipFile()) 
      { 
       if (Password != string.Empty) 
        zip.Password = Password; 
       zip.CompressionLevel = Utility.GetCompressionLevel(CompressionType); 
       foreach (string item in Paths) 
       { 
        if (IsDirectory(item)) 
         zip.AddDirectory(item); 
        else if (IsFile(item)) 
         zip.AddFile(item); 
       } 
       zip.Save(SaveFileName); 
      } 
      return ExplorerResource.ResourceManager.GetString("ZipSuccess"); 
     } 
     catch (Exception ex) 
     { 
      return ex.Message; 
     } 
    }

カスタムクラス：ZIPプログラムの

public class Utility 
    { 
     public static Ionic.Zlib.CompressionLevel GetCompressionLevel(string Expression) 
     { 
      Ionic.Zlib.CompressionLevel result = Ionic.Zlib.CompressionLevel.None; 
      if (Ionic.Zlib.CompressionLevel.BestCompression.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.BestCompression; 
      if (Ionic.Zlib.CompressionLevel.BestSpeed.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.BestSpeed; 
      if (Ionic.Zlib.CompressionLevel.Default.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Default; 
      if (Ionic.Zlib.CompressionLevel.Level0.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level0; 
      if (Ionic.Zlib.CompressionLevel.Level1.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level1; 
      if (Ionic.Zlib.CompressionLevel.Level2.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level2; 
      if (Ionic.Zlib.CompressionLevel.Level3.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level3; 
      if (Ionic.Zlib.CompressionLevel.Level4.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level4; 
      if (Ionic.Zlib.CompressionLevel.Level5.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level5; 
      if (Ionic.Zlib.CompressionLevel.Level6.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level6; 
      if (Ionic.Zlib.CompressionLevel.Level7.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level7; 
      if (Ionic.Zlib.CompressionLevel.Level8.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level8; 
      if (Ionic.Zlib.CompressionLevel.Level9.ToString().ToUpper() == Expression.Trim().ToUpper()) 
       result = Ionic.Zlib.CompressionLevel.Level9; 

      return result; 
     }

GUI：

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