Re: DependencyProperty problem - WPF Discussion Boards

3-Feb-09 8:49

MVVM is a design pattern called Model View ViewModel that's made a big hit in the WPF world. User controls form a large part of the way this pattern works. Josh Smith has written a really good introductory article on it in this months MSDN[^] magazine and Karl Shifflett has recently talked about it on Channel 9[^] (you owe it to yourself just to see his Hawaiian shirt).

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

Re: User Controls Rock!!!!

Jammer5-Feb-09 6:46

Jammer

5-Feb-09 6:46

Wait man ... go to my articles and read UserControl == DataTemplate ...

But get a bucket ready first to catch all the dribbles ... Wink | ;)

Jammer
My Blog | Article(s)

"Silverlight" vs "WPF Web Browser App"

devvvy1-Feb-09 16:48

devvvy

1-Feb-09 16:48

are they the same? Silverlight - and - "WPF Web Browser App"?

Thanks

dev

Re: "Silverlight" vs "WPF Web Browser App"

Pete O'Hanlon2-Feb-09 4:56

2-Feb-09 4:56

No. WPF Web Browser App is an XBAP.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

Re: "Silverlight" vs "WPF Web Browser App"

salon9-Feb-09 21:55

salon

9-Feb-09 21:55

http://blogs.msdn.com/jennifer/archive/2008/05/06/when-should-i-use-wpf-vs-silverlight.aspx[^]

DependencyProperty problem

schiebel-t31-Jan-09 7:58

schiebel-t

31-Jan-09 7:58

Hello all,
Im working on an ColorPicker user control and have problems registering DependencyPropertys.
I try to register a new DependencyProperty in Visual Studio 2008 and all is working fine so far.
Now i open Expression blend, add an reference to the ColorPicker.dll, and add a new instance to the window.
When i now build the solution i get an exeption:
"the property IsCurrentColor has allready been registerd from _ColorPicker"
and the usercontrol cant anymore viewed in expression blend. Im a little confused because the
application anyway started and all is working. Here is a little code of mine.

public partial class _ColorPicker
   {        
        private readonly DependencyProperty IsCurrentColorProperty;       

        public _ColorPicker()
	{
	        this.InitializeComponent();            

                IsCurrentColorProperty = DependencyProperty.Register(
                "IsCurrentColor", typeof(Color), typeof(_ColorPicker),
                new FrameworkPropertyMetadata(Color.FromRgb(255, 255, 255),
                new PropertyChangedCallback(OnIsCurrentColorChanged)));
        }
        private void OnIsCurrentColorChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
        {
            SetColorInfos((Color)e.NewValue);
            _currentColor.Background = new SolidColorBrush((Color)e.NewValue);
            //RaiseEvent(new RoutedEventArgs(this.iCurrentColorChangedEvent, (Color)e.NewValue));
        }
   }

Re: DependencyProperty problem

Insincere Dave31-Jan-09 11:13

Insincere Dave

31-Jan-09 11:13

Dependency properties need to be static, you may want to download some snippets. There are some basic ones built in (Try propdp[TAB]) and a few others from different sources try http://drwpf.com/blog/Home/tabid/36/EntryId/22/Default.aspx.

Re: DependencyProperty problem

Pete O'Hanlon1-Feb-09 8:30

1-Feb-09 8:30

As Dave said - Dependency Properties need to be static. As well as Dr WPFs snippets, you may want to download MoXAML and install it in Visual Studio. One of the addin commands allows you to add boilerplate dependency properties just by filling in a dialog box. Follow my sig for the addin.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

How to Change the Resources at runtime in WPF Application?

sankarlearns30-Jan-09 13:40

sankarlearns

30-Jan-09 13:40

Hi,

I am new to WPF. I started to develope an sample inventory management application.
I have created a form with some buttons and on click of that button the corresponding forms open.

Now i wanted have used 2 Resource Dictionary called as blue.xaml and green.xaml.
both the xaml contains the same elements but only different in their colour code
During design time i have used blue.xaml.
I want to change use the green.xaml on click of button. how can i do that?

Please Help!
Thanks
San

Re: How to Change the Resources at runtime in WPF Application?

Jammer1-Feb-09 10:40

Jammer

1-Feb-09 10:40

You need to have a read of this ...

http://www.codeproject.com/KB/WPF/wpfskins.aspx[^]

Jammer
My Blog | Article(s)

Re: How to Change the Resources at runtime in WPF Application? [modified]

sankarlearns3-Feb-09 11:29

sankarlearns

3-Feb-09 11:29

Thank you! It Helps me a lot!

i just now found this http://69.10.233.10/KB/WPF/SkinningInWPF.aspx[^]

this is little easy for me.

modified on Tuesday, February 3, 2009 8:21 PM

WPF ListView/Items Control - Another problem

snblackout30-Jan-09 13:21

snblackout

30-Jan-09 13:21

Hi there, I posted yesterday a problem that I've fixed, but now I ran into another one. This is not a conversion problem, more like a bug.

Please do the following in Bea's project to reproduce.

1. Open 'DataSource.cs'
2. Make the 'public Album()' look like below

public Album()
		{
			this.PicturesLeft = new ObservableCollection<picture>();
            this.PicturesRight = new ObservableCollection<picture>();

            this.PicturesLeft.Add(new Picture(new Uri("Images\\2moons_2.gif", UriKind.Relative), "Saturn", "Saturn is the most distant of the five planets known to ancient stargazers."));
            this.PicturesLeft.Add(new Picture(new Uri("Images\\earglobe.gif", UriKind.Relative), "Earth", "Earth, our home planet, is the only planet in our solar system known to harbor life."));
            this.PicturesLeft.Add(new Picture(new Uri("Images\\jupglobe.gif", UriKind.Relative), "Jupiter", "With its numerous moons and several rings, the Jupiter system is a \"mini-solar system.\""));
            this.PicturesLeft.Add(new Picture(new Uri("Images\\marglobe.gif", UriKind.Relative), "Mars", "The red planet Mars has inspired wild flights of imagination over the centuries."));
            this.PicturesLeft.Add(new Picture(new Uri("Images\\merglobe.gif", UriKind.Relative), "Mercury", "The small and rocky planet Mercury is the closest planet to the Sun."));
            this.PicturesLeft.Add(new Picture(new Uri("Images\\nepglobe.gif", UriKind.Relative), "Neptune", "Neptune was the first planet located through mathematical predictions."));
            this.PicturesLeft.Add(new Picture(new Uri("Images\\plutoch_2.gif", UriKind.Relative), "Pluto", "Long considered to be the smallest, coldest, and most distant planet from the Sun."));
            this.PicturesLeft.Add(new Picture(new Uri("Images\\uraglobe.gif", UriKind.Relative), "Uranus", "Uranus gets its blue-green color from methane gas above the deeper cloud layers."));
            this.PicturesLeft.Add(new Picture(new Uri("Images\\venglobe.gif", UriKind.Relative), "Venus", "At first glance, if Earth had a twin, it would be Venus."));

            int i;

            for (i = 0; i <= 3; i++) 
            {    
                this.PicturesRight.Add(new Picture(new Uri("Images\\2moons_2.gif", UriKind.Relative), "Saturn", "Saturn is the most distant of the five planets known to ancient stargazers."));
                this.PicturesRight.Add(new Picture(new Uri("Images\\earglobe.gif", UriKind.Relative), "Earth", "Earth, our home planet, is the only planet in our solar system known to harbor life."));
                this.PicturesRight.Add(new Picture(new Uri("Images\\jupglobe.gif", UriKind.Relative), "Jupiter", "With its numerous moons and several rings, the Jupiter system is a \"mini-solar system.\""));
                this.PicturesRight.Add(new Picture(new Uri("Images\\marglobe.gif", UriKind.Relative), "Mars", "The red planet Mars has inspired wild flights of imagination over the centuries."));
                this.PicturesRight.Add(new Picture(new Uri("Images\\merglobe.gif", UriKind.Relative), "Mercury", "The small and rocky planet Mercury is the closest planet to the Sun."));
                this.PicturesRight.Add(new Picture(new Uri("Images\\nepglobe.gif", UriKind.Relative), "Neptune", "Neptune was the first planet located through mathematical predictions."));
                this.PicturesRight.Add(new Picture(new Uri("Images\\plutoch_2.gif", UriKind.Relative), "Pluto", "Long considered to be the smallest, coldest, and most distant planet from the Sun."));
                this.PicturesRight.Add(new Picture(new Uri("Images\\uraglobe.gif", UriKind.Relative), "Uranus", "Uranus gets its blue-green color from methane gas above the deeper cloud layers."));
                this.PicturesRight.Add(new Picture(new Uri("Images\\venglobe.gif", UriKind.Relative), "Venus", "At first glance, if Earth had a twin, it would be Venus."));
            }     
		           
		}
</picture></picture>

3. Run it

Notice that if you scroll to the bottom of the ListView the drag & drop stops working but if you scroll back to the top, the drag & drop works. Also if you use the keyboard to arrow up/dwn in the listview the drag & drop works until you scroll via the mouse wheel or the scrollbar.

If you have 18 items in the ListView it works fine, add anymore and it starts messing up.

This one I've narrowed down to 1 line of code that isn't working when you are at the bottom of the list. This is from "Utilities.cs-->GetItemContainer"

var firstContainer = itemsControl.ItemContainerGenerator.ContainerFromIndex(0);

Anyone have any ideas?

Thanks

Re: WPF ListView/Items Control - Another problem

Insincere Dave31-Jan-09 4:08

Insincere Dave

31-Jan-09 4:08

Disable item virtualization by adding VirtualizingStackPanel.IsVirtualizing="False" to the ListViews XAML, although if your going too be dealing with 100s of items you might want to look for a different solution.

Re: WPF ListView/Items Control - Another problem

snblackout31-Jan-09 7:56

snblackout

31-Jan-09 7:56

That did the trick. I have to ask though, why would I need to look for a different solution than the ListView for item counts greater than 100? What is the problem?

Re: WPF ListView/Items Control - Another problem [modified]

Insincere Dave31-Jan-09 10:30

Insincere Dave

31-Jan-09 10:30

That piece of code disables item virtualization which improves performance by only creating the items that are visible and regenerating them as you scroll. See MSDN.
Heres an altered version of that method that worked with virtualization enabled. It uses a method which was added in .NET 3.5 but Im guessing your using that as otherwise the sample would have probably worked.

public static FrameworkElement GetItemContainer(ItemsControl itemsControl, Visual bottomMostVisual)
{
	return itemsControl.ContainerFromElement(bottomMostVisual) as FrameworkElement;
}

You can see the effects by trying with and without virtualization if you add more iterations to your loop which adds the pictures. At 200 there was a noticable pause when it was disabled.

modified on Saturday, January 31, 2009 5:18 PM

Re: WPF ListView/Items Control - Another problem

snblackout2-Feb-09 8:59

snblackout

2-Feb-09 8:59

That worked great, thanks for all your help, I really appreciate it. I'm learning! Laugh | :laugh:

Windows1 Elements

me0830-Jan-09 12:26

me08

30-Jan-09 12:26

Hi I am in the middle of creating my 1st proper application and after just toying about with wpf for the last couple days.

I have once class called AccessDb.cs which hold various DB functions

and the Window1.xaml and cs

in accessdb , i have some code to open a database extract data via a datareader and I want to add this on the fly(no data binding) to a combobox in xaml in windows1.

How to you access elements in window1 from another class?

i.e window1.combobox1.items.add(datareader[manufacturers].tostring())

Thanks, such a noob question

oops im using c#

BlitzPackage2-Feb-09 11:30

BlitzPackage

2-Feb-09 11:30

All you have to do in the other class is pass in a reference to Window1.

So, for example, one way to do this is to declare a method in your other class that gets a reference to a Window1 object:

public void GetWindowReference(Window1 theWindow)
{
     // Do some work
}

Then, in Window1 you can just code:

OtherClass myOtherClass = new OtherClass();
myOtherClass.GetWindowReference(this);

Then you can do what you will with with Window1.

Let me know if that helps; you need more information; or want to try another method.

me082-Feb-09 11:53

me08

2-Feb-09 11:53

Ah Thanks , I a bit noob on the basics, that has helped me heaps. owe you a crate of beer , cheers

Smile | :)

Pete O'Hanlon2-Feb-09 11:42

2-Feb-09 11:42

When you extract your data, put it into a well defined class. For instance, if you were reading in an animals structure, you might have a class that looks like this:

public class Animal
{
  public string Name { get; set; }
}

Create an observable collection that wraps the animals and populate it with your data reader. [Hint - you might want to use my RangeObservableCollection[^] class in place of the ObservableCollection because it's better suited for bulk loading information into without firing off the notification events]. Then, bind this to your DataContext and use WPF databinding to bind the combobox to this. I know this seems to be a lot, but it's not as bad as it sounds and there are plenty of examples on this.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

BlitzPackage2-Feb-09 11:45

BlitzPackage

2-Feb-09 11:45

Indeed, I was going to recommend an observable collection; but he said he did not want any databinding.

Come to think of it; why do you not want databinding? Just curious.

Pete O'Hanlon2-Feb-09 11:46

2-Feb-09 11:46

BlitzPackage wrote:
why do you not want databinding?

Masochism - plain and simple masochism.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

me084-Feb-09 5:04

me08

4-Feb-09 5:04

Haven't got round to learning databinding yet, just trying a few simple things with basics.

when i tried the solution above i get

Error 1 'BikeMaint.Modules.AccessDB.GetBikesAlreadyStored(BikeMaint.Window1)' is inaccessible due to its protection level G:\Programming\Projects\bikemaint\Window1.xaml.cs 103 18 BikeMaint

?

Pete O'Hanlon4-Feb-09 5:20

4-Feb-09 5:20

It means that the method GetBikesAlreadyStored isn't declared as public or internal (assuming it's all in the same assembly) so it can't be accessed by an object outside its class. You've probably got it declared as private or protected (or without a scope identifier at all).

"WPF has many lovers. It's a veritable porn star!" - Josh Smith