Secretbytes's Weblog

Finding registered application for an extension.

secretbytes — Tue, 16 Dec 2008 17:44:02 +0000

One day my colleague asked me if there is a way to know the registered application to a specific extension, or how OS executes Notepad when user double clicks on any txt files. Here is my finding over it.

And here is the sample application source

using System;
using Microsoft.Win32;
 
namespace FileAssociationCheck
{
class Program
{
static void Main(string[] args)
{
while (true)
{
Console.WriteLine(“Extension:”);
string val = GetAssociatedFileName(Console.ReadLine());
Console.WriteLine(val);
 
}
}
private static string GetAssociatedFileName(string Extension)
{
RegistryKey ClassRoot = Registry.ClassesRoot;
String AssociatedFileName = “”;
 
if (ClassRoot != null)
{
try
{
RegistryKey ExtensionKey = ClassRoot.OpenSubKey(Extension);
if (ExtensionKey != null)
{
string ExtensionValue = (string) ExtensionKey.GetValue(“”);
RegistryKey FileTypeKey = ClassRoot.OpenSubKey(ExtensionValue);
if (FileTypeKey != null)
{
RegistryKey ShellKey = FileTypeKey.OpenSubKey(“shell”);
if (ShellKey != null)
{
String FileType = (String) ShellKey.GetValue(“”);
AssociatedFileName = String.IsNullOrEmpty(FileType)
? OpenDefaultKey(ShellKey)
: OpenSpecifiedKey(ShellKey, FileType);
}
FileTypeKey.Close();
}
ExtensionKey.Close();
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
ClassRoot.Close();
 
}
return ParseString(AssociatedFileName);
 
}
private static readonly char[] nonChars = new[] {‘&’,‘”‘, ‘/’,‘%’,‘*’};
private static string ParseString(string name)
{
 
name = name.Trim(nonChars);
string[] split = name.Split(nonChars);
if(split.Length >0)
{
string str= split[0].Trim();
return str;
}
return “”;
}
private static string OpenSpecifiedKey(RegistryKey ShellKey, string CommandType)
{
string Value = “”;
RegistryKey SpecifiedKey = ShellKey.OpenSubKey(CommandType);
if(SpecifiedKey==null)
{
string[] names = ShellKey.GetSubKeyNames();
if(names.Length>0)
{
SpecifiedKey = ShellKey.OpenSubKey(names[0]);
}
}
if (SpecifiedKey != null)
{
RegistryKey CommandKey = SpecifiedKey.OpenSubKey(“command”);
if (CommandKey != null)
{
Value = (string)CommandKey.GetValue(“”);
CommandKey.Close();
 
}
SpecifiedKey.Close();
}
return Value;
}
private static string OpenDefaultKey(RegistryKey ShellKey)
{
String Value = “”;
RegistryKey OpenKey = ShellKey.OpenSubKey(“Open”);
if(OpenKey==null)
{
string[] names = ShellKey.GetSubKeyNames();
if(names.Length>0)
{
OpenKey = ShellKey.OpenSubKey(names[0]);
}
}
if (OpenKey != null)
{
RegistryKey CommandKey = OpenKey.OpenSubKey(“Command”);
if (CommandKey != null)
{
Value= (string) CommandKey.GetValue(“”);
CommandKey.Close();
 
}
OpenKey.Close();
}
 
return Value;
}
}
}
The program produce output as
Extension:

.msi

G:\WINDOWS\System32\msiexec.exe

Extension:

.dll

E:\Reverse engineering\Software\Olly Engines\odbg110 Shadow\Shadow.exe

Extension:

.rar

G:\Program Files\WinRAR\WinRAR.exe

Extension:

.dfaff
Extension:

.txt

G:\WINDOWS\system32\NOTEPAD.EXE

Extension:

.docx

G:\Program Files\Microsoft Office\Office12\WINWORD.EXE

Extension:

.doc

G:\Program Files\Microsoft Office\Office12\WINWORD.EXE

Extension:

.elx
Extension:

.msg

G:\Program Files\Microsoft Office\Office12\OUTLOOK.EXE

Extension:

.rar

G:\Program Files\WinRAR\WinRAR.exe

Extension:

.7z

G:\Program Files\WinRAR\WinRAR.exe

Extension:

Different ways to cut the current line(VS 2008)

secretbytes — Mon, 27 Oct 2008 17:23:02 +0000

In earlier days if I had to cut the current line from the visual studio I used to select all the line, keeping Cursor at the beginning and pressing Shift+End key to select the whole line and Cut the line using Ctrl+X, later I knew I could only use Ctrl+X without selecting anything from the line.Again later I knew there was another way to do the same job; keeping cursor at the desired line and pressing Shift+Delete. Again later I found Ctrl+L would also perform the same job. So there are 4 ways I know choose whatever suits you best.

Copying Text From MessageBox

secretbytes — Thu, 16 Oct 2008 05:20:03 +0000

Ever wondered you could actually copy text from a MessageBox. I found this great gem in one blog(sorry I forgot the name).

Press Ctrl+C while MessageBox has a focus.

This produces output as:

—————————

Error

—————————

Some Error Code: 0x0123456F

—————————

—————————.

This really helps your frustrating minutes to write those Error code manually to a text editor.

Isn’t it a great tip?

LinQ!!Getting the associated file icons

secretbytes — Fri, 12 Sep 2008 06:01:35 +0000

LinQ has always fascinated me ever since it was first released and I have been learning it ever since. The following snippet could act as a tutorial, especially to the beginners thriving to learn LinQ. Before writing this, I did a bit of browsing on how to get the associated icon for the file extension. I found many likely hits using primitive techniques but none using LinQ. So I decided to write one myself. Even though the code isn’t optimized, it does what it is meant to do and more, it is quite simple to read and understand. Here goes:

var x = from A in
from B in
from C in
from D in
(from E in Registry.ClassesRoot.GetSubKeyNames()
where
E.StartsWith(“.”)
select
new
{   Extension = E,
Key =
Convert.ToString(Registry.ClassesRoot.OpenSubKey(E).GetValue(“”))
})
where D != null
select new {D.Extension, Ico = Registry.ClassesRoot.OpenSubKey(D.Key)}
where C.Ico != null
select new {C.Extension, Val = C.Ico.OpenSubKey(“DefaultIcon”)}
where B.Val != null
select new {B.Extension, FilePath = B.Val.GetValue(“”) as String}
where A != null && A.FilePath != null && A.FilePath.Split(‘,’).Length > 1
select
new
{
A.FilePath,
A.Extension,
Icon =
My.Utilities.IconExtractor.GetIcon(A.FilePath.Split(‘,’).ToArray()[0],
Convert.ToInt32(A.FilePath.Split(‘,’).ToArray()[1]))
};

And another utility class to extract icon from file.

namespace My.Utilities
{
using System;
using System.Runtime.InteropServices;
using System.Drawing;


public class IconExtractor
{
[DllImport("Kernel32.dll")]
static extern int GetModuleHandle(string lpModuleName);

[DllImport("Shell32.dll")]
static extern IntPtr ExtractIcon(int Hinst, string FileName, int IconIndex);

[DllImport("User32.dll")]
static extern int DestroyIcon(IntPtr hIcon);

public static Icon GetIcon(string fileName,int index)
{
IntPtr HIcon=IntPtr.Zero;
try
{
HIcon = ExtractIcon(GetModuleHandle(String.Empty), fileName, index);
if (HIcon == IntPtr.Zero) return null;
return Icon.FromHandle(HIcon).Clone() as Icon;
}
finally
{
DestroyIcon(HIcon);
}


}


}
}

RichTextBox without Image

secretbytes — Fri, 25 Jul 2008 06:54:13 +0000

One of my friend asked me if there is a way that could prevent Images being pasted in the RichTextBox control, so I did a little code that allows RichTextBox control not to include Images.
The solution to this problem is very simple just override the OnKeyDown event and check if the clipboard contains data of Bitmap Type.

public class RichTextBoxWithoutImage:RichTextBox
{
protected override void OnKeyDown(KeyEventArgs e)
{
base.OnKeyDown(e);
/*check for Ctrl+V*/
if (e.Control && e.KeyCode == Keys.V)
{
IDataObject obj = Clipboard.GetDataObject();
if (obj.GetDataPresent(typeof(Bitmap)))
{
e.Handled = true;
}
}
}
}

Getting information string from enum

secretbytes — Fri, 18 Jul 2008 07:24:17 +0000

The Idea came while I was writing a wrapper for PE file structure early this year that was even before I ever started writing bog. Loads of Enum has to be provided with their information. The solution was simple, attach a custom attribute to each member of the Enum and later retrieve them using reflection.

Here is how I did it all,

Create Attribute class i.e., Info ,

public class Info : Attribute
{
string _name;
public string Name
{
get { return _name; }
set { _name = value; }
}
public Info(string name)
{
this._name = name;
}
}

Secondly the meat of all is a function that retrieves the info from the Enum member

public string GetInfo<T>(T c)
{
Type t = c.GetType();
if (t.BaseType.Equals(typeof(Enum)))
{
FieldInfo fn = t.GetField(c.ToString());
Info[] values = (Info[])fn.GetCustomAttributes(typeof(Info), false);
if(values.Length>0)
{
return values[0].Name;
}
}
return “”;

}

Remember the function is made generic and used to retrieve info from any Enum type.

For LinQ nerd one extension method.

public static class Extensions
{
public static string GetInfo(this Enum c)
{
Type t = c.GetType();
/*if (t.BaseType.Equals(typeof(Enum)))
 {*/
FieldInfo fn = t.GetField(c.ToString());
Form1.Info[] values = (Form1.Info[])fn.GetCustomAttributes(typeof(Form1.Info), false);
if (values.Length > 0)
{
/*Only top value*/
return values[0].Name;
}
/*}*/
return “”;
}
}

Sample:

public enum Car
{
[Info("I am ferrary")]
Ferrary,
[Info("I am BMW")]
BMW,

}
public enum Direction
{
[Info("I am North")]
North,
[Info("I am East")]
East,
[Info("I am West")]
West,
[Info("I am South")]
South,

}

private void DisplayInfo()
{

Console.WriteLine(GetInfo(Car.Ferrary));
Console.WriteLine(GetInfo(Direction.West));
/*using Extension Method*/
Console.WriteLine(Direction.North.GetInfo());


}

7-zip wrapper, Extracting password protected file

secretbytes — Thu, 10 Jul 2008 05:37:17 +0000

Recently there has been a 7-zip C# wrapper library in codeproject.com written by Eugene Sichkar. The author has done a tremendously great job he deserves a thank.

By default user can not simply use the native 7z.dll directly into the C# project this is because of the incomplete COM interfaces implementations in 7-Zip code. So his wrapper comes to a rescue but author says the wrapper is incomplete in fact it lacks everything (I don’t think he is true). What I found is Currently wrapper doesn’t support extract feature for password protected files.I tweak his wrapper class to make it work for password protected files

Looking in to the 7zip original source code. When user calls the extract method first it tries to Query for ICryptoGetTextPassword in the IArchiveExtractCallback .

Line no: 634 (7z457\CPP\7zip\Archive\Rar\RarHandler.cpp)

if (!getTextPassword)
extractCallback.QueryInterface(IID_ICryptoGetTextPassword,
&getTextPassword);

I am now tweaking the wrapper for IArchiveExtractCallback interface by inheriting it from the ICryptoGetTextPassword. As

[ComImport]
[Guid("23170F69-40C1-278A-0000-000600200000")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IArchiveExtractCallback:ICryptoGetTextPassword
{
void SetTotal(ulong total);
void SetCompleted([In] ref ulong completeValue);

[PreserveSig]
int GetStream(
uint index,
[MarshalAs(UnmanagedType.Interface)] out ISequentialOutStream outStream,
AskMode askExtractMode);
// GetStream OUT: S_OK – OK, S_FALSE – skeep this file

void PrepareOperation(AskMode askExtractMode);
void SetOperationResult(OperationResult resultEOperationResult);
}

Thus, our callback ,to get the password ,is now invoked from native 7zip as

Line: 640 (7z457\CPP\7zip\Archive\Rar\RarHandler.cpp)

RINOK(getTextPassword->CryptoGetTextPassword(&password));

The callback return 0 if success and 1 if error.

So now ArchiveCallback class looks like

class ArchiveCallback : IArchiveExtractCallback
{
private uint FileNumber;
private string FileName;
private OutStreamWrapper FileStream;

public ArchiveCallback(uint fileNumber, string fileName)
{
this.FileNumber = fileNumber;
this.FileName = fileName;
}

 #region IArchiveExtractCallback Members

public void SetTotal(ulong total)
{
}

public void SetCompleted(ref ulong completeValue)
{
}

public int GetStream(uint index, out ISequentialOutStream outStream, AskMode askExtractMode)
{
if ((index == FileNumber) && (askExtractMode == AskMode.kExtract))
{
string FileDir = Path.GetDirectoryName(FileName);
if (!string.IsNullOrEmpty(FileDir))
Directory.CreateDirectory(FileDir);
FileStream = new OutStreamWrapper(File.Create(FileName));

outStream = FileStream;
}
else
outStream = null;

return 0;
}

public void PrepareOperation(AskMode askExtractMode)
{
}

public void SetOperationResult(OperationResult resultEOperationResult)
{
FileStream.Dispose();
Console.WriteLine(resultEOperationResult);
}

 #endregion

 #region ICryptoGetTextPassword Members


public int CryptoGetTextPassword(out string password)
{

password = “secretbytes.wordpress.com”;
return 0;
}

 #endregion
}

Switch Builder

secretbytes — Fri, 20 Jun 2008 06:32:18 +0000

I had to write a switch case for an Enum that contains huge amount of members. Writing each case with hitting the keyword is frustrating and time consuming. So I wrote a little code that builds a switch case for every member of Enum in an Assembly.

The Logic behind the scene is extremely simple. What one need to do is.

load an assembly
Enumerate all Enum types from the loaded assembly.
Build the switch case

Load and Enumerat all Enums from an assembly and store it in a combo box

private void LoadAsm(String Path)
{
/*Load an Assembly*/
Assembly asm = Assembly.LoadFile(Path);
if (asm != null)
{
Type[] tp = asm.GetTypes();
foreach (Type t in tp)
{
/*If type is Enum add it to tne combobox*/
if (t.IsEnum && t.BaseType == typeof(Enum))
{
this.comboBox1.Items.Add(t);
}
}
}
}

Now, All enums are loaded into combobox. Time to build the switch case

private void BuildSwitch()
{
Type t = this.comboBox1.SelectedItem as Type;
StringBuilder sb = new StringBuilder();
sb.AppendLine(String.Format(“{0} Enm;”, t.Name));
sb.AppendLine(“switch(Enm)”);
sb.AppendLine(“{“);

/*Prepare case for each name of the enum*/
foreach (string str in Enum.GetNames(t))
{
sb.AppendLine(string.Format(“case {0}.{1}:”, t.Name,str));
sb.AppendLine(“break;”);

}
sb.AppendLine(“}”);
this.richTextBox1.Text = sb.ToString();
}

Glassy Control

secretbytes — Sun, 01 Jun 2008 13:56:53 +0000

I was fiddling with panel appearance as I wanted it to have a Glassy effect. I don’t know if I got it exactly what I wanted but the result somehow looks appealing. You can also play with it especially into Rectangles for better results (well, don’t know if it makes).

code goes:

protected override void OnPaint(PaintEventArgs e)
{
e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
Rectangle FullRectangle = new Rectangle(0, 0, this.Width, this.Height);
Rectangle HalfRectangle = new Rectangle(0, this.Height/2, this.Width, this.Height);

Point StartPoint = new Point(0, FullRectangle.Top);
Point EndPoint = new Point(0, FullRectangle.Bottom);

LinearGradientBrush Painter = new LinearGradientBrush(StartPoint,EndPoint, Color.White, this.BackColor);
e.Graphics.FillRectangle(Painter, FullRectangle);
EndPoint = new Point(0, HalfRectangle.Top);
StartPoint = new Point(0, HalfRectangle.Bottom);
Painter = new LinearGradientBrush(EndPoint, StartPoint, this.BackColor, Color.White);
e.Graphics.FillRectangle(Painter, HalfRectangle);

}

And Output looks,

IComparer How to

secretbytes — Thu, 08 May 2008 07:09:23 +0000

Sometimes, when sorting real object life no longer remains easier as it is whilst making sort operation in simple data types. Consider a following example, you are about the sort cars from its collection. How do you do this? There is in fact no operator like <, >, == that meets your all requirements unless you code them explicitly.
As everyone has already known about ArrayList class, that contains a public method Sort(), Luckily user can also feed parameter about how sorting method will proceed.
Parameter I am talking about is IComparer interface that provides only one method.
The implementation is self-explanatory.

using System;
using System.Collections.Generic;
using System.Text;
using System.Collections;

namespace IcomparableTest
{
public class Car:IComparable
{
string _modelName;
/// 
/// Modle Name of the car
/// 
public string ModelName
{
get { return _modelName; }
set { _modelName = value; }
}


DateTime _manufactureDate;
/// 
/// Manufacture Date
/// 
public DateTime ManufactureDate
{
get { return _manufactureDate; }
set { _manufactureDate = value; }
}
int _modleno;
/// 
/// Model Number
/// 
public int ModelNumber
{
get { return _modleno; }
set { _modleno = value; }
}

public Car(string modlename,DateTime manufacturedate,int modleno)
{
_modleno = modleno;
_modelName = modlename;
_manufactureDate = manufacturedate;
}


#region IComparable Members

/// 
/// Default comprision, Generates compresion from ModleName
/// 
/// object to compare to
/// 
public int CompareTo(object obj)
{
Car temp = null;
if(obj is Car)
{
temp = obj as Car;
return temp._modelName.CompareTo(this._modelName);
}
throw new Exception(“Object should be of Car type”);
}
/// 
/// Compare object
/// 
/// object to comparet to
/// 
/// 
public int CompareTo(Object obj,CarComparer.ComparisonType ComparisionType)
{
Car obj1 = obj as Car;
if (obj != null)
{

switch (ComparisionType)
{
case CarComparer.ComparisonType.ManufactureDate:
return _manufactureDate.CompareTo(obj1._manufactureDate);
case CarComparer.ComparisonType.ModleName:
return _modelName.CompareTo(obj1._modelName);
case CarComparer.ComparisonType.ModleNo:
default:
return _modleno.CompareTo(obj1._modleno);

}
}
throw new Exception(“Object should be of Car type”);


}

#endregion
public override string ToString()
{
return (string.Format(“Model Name: {0}, Modle Number: {1}, Manufacture Date: {2}”,
this._modelName,
this._modleno,
this._manufactureDate.ToLongDateString()));
}
}

public class CarComparer:IComparer
{
public enum ComparisonType
{
ModleName,
ManufactureDate,
ModleNo,
}

private ComparisonType _cmpType;
public ComparisonType ComparisonWay
{
get { return _cmpType; }
set { _cmpType = value; }
}
public CarComparer(ComparisonType CompType)
{
_cmpType = CompType;
}
public CarComparer():this(ComparisonType.ModleName)
{

}

#region IComparer Members

public int Compare(object x, object y)
{
if((x is Car) && (y is Car) )
{

return (x as Car).CompareTo((y as Car), this._cmpType);

}
throw new Exception(“Object should be of Car type”);





}

#endregion
}
}

And Here is the Sample application source.

private void button1_Click(object sender, EventArgs e)
{
Car c = new Car(“Mercedes”, DateTime.Today, 101);
Car c1 = new Car(“Ferrary”,c.ManufactureDate.Subtract(new TimeSpan(1,0,0,0,0)), 20);
Car c2 = new Car(“Mitsubishi”, c1.ManufactureDate.Subtract(new TimeSpan(1, 0, 0, 0, 0)), 40);
Car c3 = new Car(“Roles-Royce “, c2.ManufactureDate.Subtract(new TimeSpan(1, 0, 0, 0, 0)), 31);



ArrayList _list = new ArrayList();
_list.Add(c);
_list.Add(c1);
_list.Add(c2);
_list.Add(c3);



this.listBox1.Items.Add(“Original placment:”);
foreach (Car x in _list)
{
this.listBox1.Items.Add(x);
}
this.listBox1.Items.Add(string.Empty);
this.listBox1.Items.Add(“Sorting by Model Number”);
_list.Sort(new CarComparer(CarComparer.ComparisonType.ModleNo));
foreach (Car x in _list)
{
this.listBox1.Items.Add(x);
}

this.listBox1.Items.Add(string.Empty);
this.listBox1.Items.Add(“Sorting by Manufacture Date”);
_list.Sort(new CarComparer(CarComparer.ComparisonType.ManufactureDate));
foreach (Car x in _list)
{
this.listBox1.Items.Add(x);
}

this.listBox1.Items.Add(string.Empty);
this.listBox1.Items.Add(“Sorting by Model Name(default sort)”);
_list.Sort(new CarComparer());
foreach (Car x in _list)
{
this.listBox1.Items.Add(x);
}

}

Sample Output: