folder creation problem during thumbnail generation c#

I am generating Thumbnails, Everything goes fine and smooth but there is a problem during the creation of sub folder. Suppose:

C:\Users\a\Desktop\b test\Iceland\Haskolinn2 the destination thumbnail folder will look like this: C:\Users\a\Desktop\a test\Iceland *C:\Users\a\Desktop\a test\Haskolinn2*

it must look like C:\Users\a\Desktop\a test\Iceland\Haskolinn2

here is the code:

 public void CreateThumbnail(double wid, double hght, bool Isprint)
    {


        string saveAt = "C:\\Users\\a\\Desktop\\a test";

string b= "C:\\Users\\a\\Desktop\\b test\\iceland"         
string [] bb = Directory.GetDirectories(b, "*.*", SearchOption.AllDirectories);

       foreach (string path in bb)
      {
            var directory = new DirectoryInfo(path);

            string outputPath = Path.Combine(saveAt, directory.Name);
            foreach (FileInfo f in directory.GetFiles("*.*", S开发者_如何学GoearchOption.AllDirectories))
            {



                if (f.DirectoryName != directory.FullName)
                {
                    outputPath = Path.Combine(saveAt, directory.Name);

                }
                if (!Directory.Exists(outputPath))
                {
                    Directory.CreateDirectory(outputPath);

                }


                using (Image imagesize = Image.FromFile(f.FullName))

                using (Bitmap bitmapNew = new Bitmap(imagesize))
                {
                    double maxWidth = wid;
                    double maxHeight = hght;
                    int w = imagesize.Width;

                    int h = imagesize.Height;
                    // Longest and shortest dimension 
                    int longestDimension = (w > h) ? w : h;

                    int shortestDimension = (w < h) ? w : h;
                    // propotionality  
                    float factor = ((float)longestDimension) / shortestDimension;

                    // default width is greater than height    
                    double newWidth = maxWidth;
                    double newHeight = maxWidth / factor;

                    // if height greater than width recalculate  
                    if (w < h)
                    {
                        newWidth = maxHeight / factor;

                        newHeight = maxHeight;
                    }

                    string fileName = Path.Combine(outputPath, Path.GetFileNameWithoutExtension(f.Name) + ".jpeg");

                    bitmapNew.GetThumbnailImage((int)newWidth, (int)newHeight, () => false, IntPtr.Zero)

                        .Save(fileName, System.Drawing.Imaging.ImageFormat.Jpeg);



                }

            }
        }
    }


}

From what I can see, I guess the Path.Combine call is not doing what you think it should.

When given two fully qualified paths, Path.Combine basically ignores the first, and returns the second. Example:

string path1 = @"C:\Test\Path\"
string path2 = @"C:\Other\Path\"
Console.WriteLine(Path.Combine(path1, path2)); //prints C:\Other\Path

In your code this means that you are not using the destination folder for the thumbnails, but the source folder. You could try stripping the full path down to a folder name, like

string path1 = @"C:\Test\Path\"
string path2 = @"C:\Other\FolderToCombine\"
DirectoryInfo di = new DirectoryInfo(path2);

Console.WriteLine(Path.Combine(path1, di.Name)); //prints C:\Test\Path\FolderToCombine

After the question edit:
The problem is that for a structure like

...A
   |-B
   |-C

your Directory.GetDirectories call will return strings like "..\A", "..\A\B" "..\A\C". When those string are used in a DirectoryInfo constructor you get directories with names of "A", "B" and "C", so in effect, you are linearizing a tree structure (Things could get really interesting if the B folder had a subfolder called A :))

You could do something like:

public void CreateThumbnail(double wid, double hght, bool Isprint)
{
   string saveAt = "C:\\Users\\a\\Desktop\\a test";  
   string b= "C:\\Users\\a\\Desktop\\b test\\iceland"
   ProcessFolder(b, saveAt, wid, hght, Isprint);
}

public static void ProcessFolder(string sourceFolder, string destFolder, double wid, double hght, bool Isprint)
{
  //create the dest folder if it does not exist
  Directory.CreateDirectory(destFolder); 

  //get info about the source folder
  DirectoryInfo diSource = new DirectoryInfo(sourceFolder);

  //get the source files (only in the current source folder)
  foreach (FileInfo f in diSource.GetFiles("*.*"))
  {
    //calculate the destination file name
    string destFileName = Path.Combine(destFolder, f.Name);
    //thumbnail processing here

    //quick test
    File.Copy(f.FullName, destFileName);
  }

  //get all subfolders for the current folder
  foreach (string dir in Directory.GetDirectories(sourceFolder, "*.*"))
  {
    //calculate the new output folder for a given subfolder
    // if the source folder is \src\a\, and the dest folder is \dest\
    // this results in \dest\a
    DirectoryInfo diSubfolder = new DirectoryInfo(dir);
    string outputPath = Path.Combine(destFolder, diSubfolder.Name);

    ProcessFolder(dir, outputPath, wid, hght, Isprint); //call recursively
  }
}

This example will copy a folder to another location, just replace the File.Copy call with your logic.