Retrieve detailed information of a File

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Introduction

This article shows, how one omitted the detail information of a file under the use of the Shell32.dll from the Windows system. Some detailed information are: Comment, Title, Subject, Category, Author, and so on.

Background

The Windows system could store additional information like author, comment, title, category... to a file, this information can be read with GetDetailsOf method from the shell32.dll.

Using the code

First of all, add a new COM reference "Microsoft Shell Controls and Automation" (shell32.dll) to your Project.

After adding the reference, simple create an instance of the CFileInfo class as in the demo project. To access the File Information, simply read the properties from the class.

try{
  // Read File Details from CFileInfo Object
  CFileInfo oDetailedFileInfo = new CFileInfo(sFileName);
  txtName.Text = oDetailedFileInfo.FileName;
  txtFiletype.Text = oDetailedFileInfo.FileType;
  txtFileSize.Text = oDetailedFileInfo.FileSize.ToString();
  txtAuthor.Text = oDetailedFileInfo.FileAuthor;
  txtCategory.Text = oDetailedFileInfo.FileCategory;
  txtComment.Text = oDetailedFileInfo.FileComment;
  txtSubject.Text = oDetailedFileInfo.FileSubject;
  txtTitle.Text = oDetailedFileInfo.FileTitle;
}catch(Exception ex){
  MessageBox.Show("Could not read File information\r\n" 
                  + ex.Message, "Error while getting Info", 
                  MessageBoxButtons.OK,MessageBoxIcon.Error);
}

Behind the Scenes

The GetDetailedFileInfo method gets all available information of a file into an ArrayList. The DetailedFileInfo class is a helper class for holding the information in a simple object within the ArrayList.

// Getting all the available Information of a File into a Arraylist
private ArrayList GetDetailedFileInfo(string sFile){
  ArrayList aReturn = new ArrayList();
  if(sFile.Length>0){
    try{
      // Creating a ShellClass Object from the Shell32
      ShellClass sh = new ShellClass();
      // Creating a Folder Object from Folder that inculdes the File
      Folder dir = sh.NameSpace( Path.GetDirectoryName( sFile ) );
      // Creating a new FolderItem from Folder that includes the File
      FolderItem item = dir.ParseName( Path.GetFileName( sFile ) );
      // loop throw the Folder Items
      for( int i = 0; i < 30; i++ ) {
        // read the current detail Info from the FolderItem Object
        //(Retrieves details about an item in a folder. 
        //For example, its size, type, or the time 
        //of its last modification.)

        // some examples:
        // 0 Retrieves the name of the item. 
        // 1 Retrieves the size of the item.
        // 2 Retrieves the type of the item.
        // 3 Retrieves the date and time that the item was last modified.
        // 4 Retrieves the attributes of the item.
        // -1 Retrieves the info tip information for the item. 

        string det = dir.GetDetailsOf( item, i );
        // Create a helper Object for holding the current Information
        // an put it into a ArrayList
        DetailedFileInfo oFileInfo = new DetailedFileInfo(i,det);
        aReturn.Add(oFileInfo);
      }

    }catch(Exception){

    }
  }
  return aReturn;
}
...

// Helper Class from holding the detailed File Informations
// of the System
public class DetailedFileInfo{
  int iID = 0;
  string sValue ="";

  public int ID{
    get{return iID;}
    set{iID=value;}
  }
  public string Value{
    get{return sValue;}
    set{sValue = value;}
  }

  public DetailedFileInfo(int ID, string Value){
    iID = ID;
    sValue = Value;
  }
}

History

• First release - 15th August 2004.

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