C#

Capturing optional groups in regular expressions?

sonam — Thu, 24 Dec 2009 19:05:21 GMT

string input = @"cool man dog no dude yes fight son";
  string pattern = @"cool (?<hello>((.)* ))   (?<h>( (dude)?)) (?(h)(?<dude>((.)*)))";

       MatchCollection matches = Regex.Matches(input, pattern, RegexOptions.ExplicitCapture
              | RegexOptions.IgnorePatternWhitespace);

            foreach (Match match in matches)
            {
                Console.WriteLine("dude=" + match.Groups["dude"].Value);
                Console.WriteLine("hello=" + match.Groups["hello"].Value);
                Console.ReadLine();
            }
/*Output-

dude=
hello= man dog no dude yes fight son

But the required output is:

/*Output-

dude=yes fight son
hello= man dog no

The target is that i want to capture "strings that have cool as first 'word' and have 'dude' word as optional in between".
Now,I want string that follows word "cool" ("man dog no") until "dude" word comes or end comes.
if "dude" word comes,I want the string that follows word "dude".

Can anybody explain me why the output is not correct or where i am wrong?
Thanks in advance.

Setting "WindowStyle=None" hides taskbar on maximizing

sonam — Wed, 22 Jul 2009 11:49:48 GMT

If you ever tried to make irregular windows in wpf and used setting windowstyle=none,You might have used some code like this to enable minimising,maximising properties for the window:

        private void Minimize_Click(object sender, RoutedEventArgs e)
        {

            this.WindowState = WindowState.Minimized;

        }

        private void Maximize_Click(object sender, RoutedEventArgs e)
        {

            this.WindowState = WindowState.Maximized;

        }

But on maximizing ,the window hides the taskbar.i.e it goes fullscreen.
To avoid that issue,You can use this code and yes,it works like a charm.

http://blogs.msdn.com/llobo/archive/2006/08/01/Maximizing-window-_2800_with-WindowStyle_3D00_None_2900_-considering-Taskbar.aspx

    public override void OnApplyTemplate()
        {
            System.IntPtr handle = (new WinInterop.WindowInteropHelper(this)).Handle;
            WinInterop.HwndSource.FromHwnd(handle).AddHook(new WinInterop.HwndSourceHook(WindowProc));
        }

        private static System.IntPtr WindowProc(
              System.IntPtr hwnd,
              int msg,
              System.IntPtr wParam,
              System.IntPtr lParam,
              ref bool handled)
        {
            switch (msg)
            {
                case 0x0024:/* WM_GETMINMAXINFO */
                    WmGetMinMaxInfo(hwnd, lParam);
                    handled = true;
                    break;
            }

            return (System.IntPtr)0;
        }

        private static void WmGetMinMaxInfo(System.IntPtr hwnd, System.IntPtr lParam)
        {
            
            MINMAXINFO mmi = (MINMAXINFO)Marshal.PtrToStructure(lParam, typeof(MINMAXINFO));

            // Adjust the maximized size and position to fit the work area of the correct monitor
            int MONITOR_DEFAULTTONEAREST =0x00000002;
            System.IntPtr monitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST);

            if (monitor != System.IntPtr.Zero)
            {
                
                MONITORINFO monitorInfo = new MONITORINFO();
                GetMonitorInfo(monitor, monitorInfo);
                RECT rcWorkArea = monitorInfo.rcWork;
                RECT rcMonitorArea = monitorInfo.rcMonitor;
                mmi.ptMaxPosition.x = Math.Abs(rcWorkArea.left - rcMonitorArea.left);
                mmi.ptMaxPosition.y = Math.Abs(rcWorkArea.top - rcMonitorArea.top);
                mmi.ptMaxSize.x = Math.Abs(rcWorkArea.right - rcWorkArea.left);
                mmi.ptMaxSize.y = Math.Abs(rcWorkArea.bottom - rcWorkArea.top);
            }

            Marshal.StructureToPtr(mmi, lParam, true);
        }

As seen above the code basically handles the WM_GETMINMAXINFO message. The sample project code is also included. Have Fun. :)

Update: A better way to get the handle to the window is to use the SourceInitialized event. This would also avoid calling ApplyTemplate everytime the window template is changedon the fly. Thanks to Hamid for pointing out the better solution. The attached project is now updated.

win.SourceInitialized += new EventHandler(win_SourceInitialized);

void win_SourceInitialized(object sender, EventArgs e)
{
System.IntPtr handle = (new WinInterop.WindowInteropHelper(this)).Handle;
WinInterop.HwndSource.FromHwnd(handle).AddHook(new WinInterop.HwndSourceHook(WindowProc));
}

What happened to my vacations

sonam — Wed, 22 Jul 2009 05:20:28 GMT

College is opening tommorow and I am thinking what i have done in past 1 and half months of vacations.

The only thing i can remember is bluz,my open source project.
Where is that p2p thing i decided earlier?
All the research papers about skype,overlay networks ,guntella etc are lying there on disk as it is.i have read them only once.I have read not understood..

The positive side of vacations is:
1)I learned a lot about WPF,Blend etc.
2) I am participating in win7 contest based on above experience.
3)I met shaun,my new co-developer of bluz..
4)I have got some books of ASP.Net by bill ,scott and WPF book by Mathew macdonald..

And now i have some web 2.0 ideas that i hope to implement as a way of parcticing this ASP.net stuff.Thats a business idea,So you might see something interesting on web soon.

So,If i look back that way,I think it was more rewarding than any of internship i could get.

Now ,its my last year of graduation,My targets include:
1)Enjoy it fully.I know thats hard but i'll have to make this year remeberable .
2)Implement business ideas.(I love making money in humanatic way).
3)Make final year Project.
The 3rd one is where i'll cut my efforts ,Becoz i don't think that really matters as compared to my learning.Also,I don't see potential partners for a cool. .Net team to make a cool project at the college.

cya guys,
cheers

I am gonna win this contest

sonam — Tue, 21 Jul 2009 19:57:10 GMT

Hii guys,
Just heard about this

https://www.code7contest.com/

If you have a little experience with MS .Net and you are as empty as me,Have a look over it.

The prizes are awesome and mouth watering .You will have to grasp a little about the windows 7 techonolgies though .But you can do that for atleast 17777$.

I am getting ready with a killer app idea..yes it is a a killer idea,Either it will Kill MS or my Laptop.lol!(Sorry bill,its a metaphor,don't take it serious.)

And the best thing is that ,My Last 2-3 months of WPF experience is what gonna be tested.
The deadline is short but thats good for me ,I am entering with an optimistic mind,Hope to see you guys at LA soon..

cheer with a beer.(I don't drink though)

New Open Source Project-Bluz(Next Generation Media Player)

sonam — Wed, 15 Jul 2009 20:49:56 GMT

hi guys.

I have just released a pre beta release of next generation media player bluz.

Link is here:

http://code.google.com/p/bluz/

Its based on vlc libraries and bass and a couple of others for various tasks.
Its in c#,WPF but if any of you would like to contribute through any means.
The UI is purely in XAML,I am not a good designer,Even all icons are made in XAML.
.
If any of you would like to contribute through coding various modules or helping me develop the website,it would be nice of you to make it a hit on windows OS.

Atleast,U guys can check out and report any bugs you find to me directly..

It requires .Net 3.5
Have a nice day.

Screenshots:

Extracting Album art from An Audio File

sonam — Thu, 11 Jun 2009 15:27:41 GMT

I have moved the tagging features for my media player application from MediaInfo to taglib-sharp.
because taglib-sharp provides writing of tags back to audio files too..
As a matter of fact,
Everything else was fine but,it took me whole half day to figure out how to display an image (album art) from taglib-sharp.

I thought to finally post this workaround.

    TagLib.File file = TagLib.File.Create((FilePath); //FilePath is the audio file location

                TagLib.IPicture pic=file.Tag.Pictures[0]; //pic contains data for image.

                MemoryStream stream = new MemoryStream(pic.Data.Data); /create an in memory stream

              Image im = new Image();

              BitmapFrame bmp = BitmapFrame.Create(stream);

              im.Source = bmp;
now u can use this image as a normal image..:)..i.e transformation,animation should be possible as usual.

cheers, i didn't got any post on web till now even after searching Novell's Repositories..Hopefully it helps to somebody out there .

I got task for summers:Study p2p architectures

sonam — Sun, 03 May 2009 12:14:44 GMT

This is in continuation to my last post in which i was confused of "what to do in summers".
After a lot of thinking,I have got the answer.
I'll study/research on "p2p architectures and there use in enterprises"...Lets see how it goes,i have semester exams next week and i have downloaded a lot of books/technical papers to get started. ..

p2p will help me distinguish my music player from others in the market...

I'll also look at using the p2p library "Brunet" which is not much publicized as gnutella ...You can see the work here:.
.
http://github.com/johnynek/brunet/tree/master

Its a work by Sir ,Oscar BoyKin at UCLA(University of California)..For a weath of softwares and knowledge/he blogs at:
http://boykin.acis.ufl.edu/

I'll make my player a true web 2.0 social app..doing some homework in p2p architectures will be good for my summers...

And I'll keep posting tuts/links or any cool things that i'll encounter in my p2p research.I am really excited for it.

Have a happy coding.

Awesome way to support plugins/AddIns in your applications

sonam — Tue, 14 Apr 2009 17:53:06 GMT

Hey all,
I can't imagine how easy it can be to develop and maintain a plugin architecture with System.AddIn and this tool
VSPipelineBuilder.. This is a visual studio addIn is an open source project by the ClrAddIn team and is really awesome.

U just define an interface/Contract and rest of the things, just a single click through that addIn.
AddIn will implement that Interface and thats it,u can use it..Cheers .........

I used it for first defining a single interface .and implemented a small AddIn.
.
then i added 2-3 interfaces and re executed that VSPipeline Builder AddIn..And it was awesome to see that every project in The Pipeline(4-5 projects) got updated accordingly.My old AddIn was still working becoz its contract was still there..
And iwas ready to implement new AddIns..Really great...It can save a lot of time when u have a lot of contracts to support various plugins/AddIns.
Below is a screenshot of an excellent demo app from jesse kaplan:

It demonstrates visual addIn also(Passing UI objects between AddIn and host)
ClrAddIn Team blogs at:
http://blogs.msdn.com/clraddins/

U can download the VSPipeline Builder from here:

http://clraddins.codeplex.com/

Cheers,And thanx to Jesse kaplan and the whole ClrAddIn team.

ListView DragDrop in WPF,multiselect

sonam — Tue, 03 Mar 2009 05:46:27 GMT

After going through the web ,I haven't got anything that i can use directly to enable drag drop between two listview controls or within same for multiple items.
The best thing available in my opinion is this one by Josh smith:
http://www.codeproject.com/KB/WPF/ListViewDragDropManager.aspx

But it is for single SelectionMode only

Another one for multiselct is this:
http://www.codeproject.com/KB/WPF/WPF_MultiSelect_DragDrop.aspx
But the second one has many limitations..
So i have done some work to extend it from there..
I don't have much time in near weeks to work on this ,So it is not that much well written.
But it will serve as the good to get u one what u want during drag drop in more graceful way....

A small project which shows demo,U can download it from here:..the code might differ a little bit but the theme remains same,,..:)

http://www.rapidshare.com/files/306026760/Listview.zip.html

The code is as follows:

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;
using System.Windows.Controls;
using System.Windows;
using System.Windows.Media;
using System.Windows.Controls.Primitives;
using System.Collections.ObjectModel;
using System.Reflection;
using System.Diagnostics;
namespace DragDropManager
{
   public class DragDropManager<T> where T:class,ICloneable
   {

        ListView listView;

       // delegate for GetPosition function of DragEventArgs and
       // MouseButtonEventArgs event argument objects. This delegate is used to reuse the code
       // for processing both types of events.
       delegate Point GetPositionDelegate(IInputElement element);

       public DragDropManager(ListView listView)
       {
           this.listView = listView;
           listView.PreviewMouseLeftButtonDown += new System.Windows.Input.MouseButtonEventHandler(listView_PreviewMouseLeftButtonDown);
           listView.Drop += new System.Windows.DragEventHandler(listView_Drop);
       }

       void listView_Drop(object sender, DragEventArgs e)
       {
           int index = this.GetCurrentIndex(e.GetPosition);

           if (index < 0)
               return;

           Dictionary<int,T> draggedItems = e.Data.GetData(typeof(Dictionary<int,T>)) as Dictionary<int,T>;

        if(sender==this.listView)

            this.listView.SelectedItems.Clear();

       int i = 0;

         ObservableCollection<T> itemsSource= this.listView.ItemsSource as ObservableCollection<T>;

           // finally insert the items into the source collection
         T dropTarget = itemsSource[index];

         if (draggedItems.ContainsValue(dropTarget)) return;


          foreach(int key in draggedItems.Keys)
          {
              T draggedItemClone = draggedItems[key].Clone() as T;
              itemsSource.Insert(index + i, draggedItemClone);


              i++;

          }


       }

       void listView_PreviewMouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
       {

           int index = this.GetCurrentIndex(e.GetPosition);

           if (index <0) return;

           // this will create the drag "rectangle"
           DragDropEffects allowedEffects = DragDropEffects.Move;

           if (this.listView.SelectedItems.Count == 0)
               return;

           Dictionary<int,T> draggedItems = new Dictionary<int, T>();



           foreach(T draggedItem in this.listView.SelectedItems)
           {
            draggedItems[this.listView.Items.IndexOf(draggedItem)] = (draggedItem as T);

           }

           T item = this.listView.Items[index] as T;

           if (!draggedItems.ContainsValue(item))
                     return;

           DragDrop.DoDragDrop(this.listView, draggedItems, allowedEffects);

       }
       ListViewItem GetListViewItem(int index)
       {
           if (this.listView.ItemContainerGenerator.Status != GeneratorStatus.ContainersGenerated)
               return null;

           return this.listView.ItemContainerGenerator.ContainerFromIndex(index) as ListViewItem;
       }

       // returns the index of the item in the ListView
       int GetCurrentIndex(GetPositionDelegate getPosition)
       {
           int index = -1;
           for (int i = 0; i < this.listView.Items.Count; ++i)
           {
               ListViewItem item = GetListViewItem(i);
           if (this.IsMouseOverTarget(item, getPosition))

               {
                   index = i;
                   break;
               }
           }
           return index;
       }

       bool IsMouseOverTarget(Visual target, GetPositionDelegate getPosition)
       {
           if (target == null)
               return false ;
           Rect bounds = VisualTreeHelper.GetDescendantBounds(target);

           Point mousePos= MouseUtilities.GetMousePosition(target);
           return bounds.Contains(mousePos);
       }
   }
}

..........................................................................
The code for MouseUtilities.cs is :

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Windows;
using System.Windows.Media;

namespace DragDropManager
{
    /// <summary>
    /// Provides access to the mouse location by calling unmanaged code.
    /// </summary>
    /// <remarks>
    /// This class was written by Dan Crevier (Microsoft).
    /// http://blogs.msdn.com/llobo/archive/2006/09/06/Scrolling-Scrollviewer-on-Mouse-Drag-at-the-boundaries.aspx
    /// </remarks>
    public class MouseUtilities
    {
        [StructLayout(LayoutKind.Sequential)]
        private struct Win32Point
        {
            public Int32 X;
            public Int32 Y;
        };

        [DllImport("user32.dll")]
        private static extern bool GetCursorPos(ref Win32Point pt);

        [DllImport("user32.dll")]
        private static extern bool ScreenToClient(IntPtr hwnd, ref Win32Point pt);

        /// <summary>
        /// Returns the mouse cursor location. This method is necessary during
        /// a drag-drop operation because the WPF mechanisms for retrieving the
        /// cursor coordinates are unreliable.
        /// </summary>
        /// <param name="relativeTo">The Visual to which the mouse coordinates will be relative.</param>
        public static Point GetMousePosition(Visual relativeTo)
        {
            Win32Point mouse = new Win32Point();
            GetCursorPos(ref mouse);

            // Using PointFromScreen instead of Dan Crevier's code (commented out below)
            // is a bug fix created by William J. Roberts. Read his comments about the fix
            // here: http://www.codeproject.com/useritems/ListViewDragDropManager.asp?msg=1911611#xx1911611xx
            return relativeTo.PointFromScreen(new Point((double)mouse.X, (double)mouse.Y));

            #region Commented Out
            //System.Windows.Interop.HwndSource presentationSource =
            //    (System.Windows.Interop.HwndSource)PresentationSource.FromVisual( relativeTo );
            //ScreenToClient( presentationSource.Handle, ref mouse );
            //GeneralTransform transform = relativeTo.TransformToAncestor( presentationSource.RootVisual );
            //Point offset = transform.Transform( new Point( 0, 0 ) );
            //return new Point( mouse.X - offset.X, mouse.Y - offset.Y );
            #endregion // Commented Out
        }
    }
}

-------------------------------------------------------------------------------------------------------------------------
I have tested the drag drop of nearly 10,000 items from one listview to another and it was excellent(milliseconds).
There are some things that i want to say:
1)If u want to this to work for all SelectionModes,U'll will to do some changes or better to checks before using selectedItems property.

2)The dragDrop between listviews will function when the two controls have same itemType(T) as the observableCollection type.
For any other type,U'll have do some little more coding .:P

3)The reason for ICloneable Interface is because if u drag and drop one item two or more times to another listview,And then select that item in the other listview,U'll get some annoying behaviour of selection.
To Overcome that,I have used IConeable Interface for the meanwhile..

If u have any questions regarding this code or feedback,u r most welcome.

And do let me know if u think to make it more graceful and well written code in near future,becoz I'll have time to work on this after 1-2 months only... hopefully....:)

Static methods in Interface

sonam — Fri, 19 Dec 2008 06:03:02 GMT

I was trying to implement an Interface by a class but i wanted to have static methods.
But C# doesn't allow static methods in interface.
After a little search,I got "why We can't have static methods in Interfaces".
suppose i have an interface,

interface IDemo
            {
                static void add();
            }
      Now we implement it:

class MyClass:IDemo
        {
            static void add()
            {
                Console.WriteLine("Added");
            }
        }
Pretty cool na.
But it won't compile.
because what if IDemo.add();
To avoid this ambiguity,
Static Methods are not allowed in Interfaces .

Note::

Although not implemented in C# the CLR does support static methods on interfaces. The drawback is that from C# you'd have to invoke them using reflection.