Re: Keep element in canvas when dragging it - WPF Discussion Boards

1-Apr-09 20:19

Hi,

I use adorners to move elements in a canvas but I want that those elements stay in the canvas bounderies. So when I drag an element over one of the bounderies, it should stay against that boundery and not cross it.

Now I only check the top and left bounderies with the Canvas.GetLeft and Canvas.GetTop. The width and height of the canvas is variable. Anybody has an idea how I can prevent the elements to cross the right and bottom bounderies?

Thx

ABitSmart1-Apr-09 21:17

1-Apr-09 21:17

Have you tried ClipToBounds[^] ?

How are you implementing the drag/drop ?

Pauwels Bart1-Apr-09 23:30

1-Apr-09 23:30

I hadn't tried it before but ClipToBounds doesn't work.

When I add a new UIElement (like an image) to the Canvas, I adorn it. That adorner adds a Thumb to each side of the UIElement and that thumbs handles the drag function.

// Handler for moving.
private void HandleMove(object sender, DragDeltaEventArgs args)
{
    // Horizontal position.
    if (StanagCanvas.GetLeft(this.AdornedElement) + args.HorizontalChange < 0)
    {
        // Crossing left boundary.
        StanagCanvas.SetLeft(this.AdornedElement, 0);
    }
    else if (StanagCanvas.GetRight(this.AdornedElement) - args.HorizontalChange < 0)
    {
        // Crossing right boundary.
        StanagCanvas.SetRight(this.AdornedElement, 0);
    }
    else
    {
        StanagCanvas.SetLeft(this.AdornedElement, StanagCanvas.GetLeft(this.AdornedElement) + args.HorizontalChange);
    }

    // Vertical position.
    if (StanagCanvas.GetTop(this.AdornedElement) + args.VerticalChange < 0)
    {
        // Crossing top boundary.
        StanagCanvas.SetTop(this.AdornedElement, 0);
    }
    else if (StanagCanvas.GetBottom(this.AdornedElement) - args.VerticalChange < 0)
    {
        // Crossing bottom boundary.
        StanagCanvas.SetBottom(this.AdornedElement, 0);
    }
    else
    {
        StanagCanvas.SetTop(this.AdornedElement, StanagCanvas.GetTop(this.AdornedElement) + args.VerticalChange);
    }
}

(StanagCanvas derives from Canvas)

Offcourse the Right and Bottom properties don't work because I allready use the Left and Top properties. The element doesn't cross the left and top boundery of the canvas.

I hope this is enough information.

ABitSmart2-Apr-09 5:05

2-Apr-09 5:05

You could do it without the Right/Top properties. Something like,

else if ( (StanagCanvas.GetLeft(this.AdornedElement) + this.AdornedElement.Width + args.HorizontalChange) > yourCanvas.Width )
{
    // Crossing right boundary.
    StanagCanvas.SetLeft(this.AdornedElement, yourCanvas.Width - this.AdornedElement.Width);
}

Pauwels Bart2-Apr-09 7:22

Re: Keep element in canvas when dragging it [modified]

2-Apr-09 7:22

I tried that already. The problem with that is that I don't have a reference to the canvas so I can't get the width of it. Or am I totally wrong Confused | :confused:

(It is weekend now for me so I can't recheck it but in a few days my mind is clear again and I can get a fresh start)

That adorner class (derives from Adorner like you know) is separated from my canvas class. I only call it when initializing a new UIElement on the canvas to adorn that element (and it stays adorned until I close the program or the UIElement is deleted). I guess that after I have added the adorner, that adorner only knows his element (this.AdornedElement) and nothing else. The actions I take from then with that adorner, can only affect Attached Properties (Like SetLeft, ... + I have made some extra attached properties in my Canvas class).

I can be totally wrong. If you want to know, I'm only programming for a few months without a proper eduction for it (I had programming on school but only basics). I'm learning it all myself (C# and WPF) and I need to make program for a company where I'm kind of an intern (1 year internship in a foreign country after getting my degree to get some experience before going to work in my own country).

Hope you can say that I'm wrong and it is that simple (but I missed something) Poke tongue | ;-P

ABitSmart2-Apr-09 7:50

2-Apr-09 7:50

Pauwels Bart wrote:
private void HandleMove(object sender, DragDeltaEventArgs args)

Who is the sender ? Is it the element in canvas ? If yes, you can do something like this,

FrameworkElement parent = ((sender as FrameworkElement).Parent as FrameworkElement;
//((sender as FrameworkElement).Parent should give you the Canvas

EDIT: forgot to mention, you can then get the Width parent.Width

modified on Thursday, April 2, 2009 2:15 PM

Pauwels Bart2-Apr-09 8:45

2-Apr-09 8:45

That looks like a good answer Big Grin | :-D

I have tried to call the parent with the sender but that didn't work. That was probably because I didn't parse it as a FrameworkElement or something like that.

I wouldn't know what to do if this site and forum didn't exists. Thx very much for the help. Thumbs Up | :thumbsup:

I will try it and let you know if it worked!

Pauwels Bart4-Apr-09 18:32

4-Apr-09 18:32

Ok, the sender was not the element in the canvas but the thumb. Luckely I can get the element with "this.AdornedElement" (standard build-in adorner function to get the adorned element).

So, the solution was:

  // Handler for moving.
  private void HandleMove(object sender, DragDeltaEventArgs args)
  {
      FrameworkElement element = this.AdornedElement as FrameworkElement;
      StanagCanvas stanagCanvas = element.Parent as StanagCanvas;

      // Horizontal position.
      if (StanagCanvas.GetLeft(element) + args.HorizontalChange < 0)
      {
          // Crossing left boundary.
          StanagCanvas.SetLeft(element, 0);
      }
      else if (StanagCanvas.GetLeft(element) + element.Width + args.HorizontalChange > stanagCanvas.Width)
      {
          // Crossing right boundary.
          StanagCanvas.SetLeft(element, stanagCanvas.Width - element.Width);
      }
      else
      {
          StanagCanvas.SetLeft(element, StanagCanvas.GetLeft(element) + args.HorizontalChange);
      }

      // Vertical position.
      if (StanagCanvas.GetTop(element) + args.VerticalChange < 0)
      {
          // Crossing top boundary.
          StanagCanvas.SetTop(element, 0);
      }
      else if (StanagCanvas.GetTop(element) + element.Height + args.VerticalChange > stanagCanvas.Height)
      {
          // Crossing bottom boundary.
          StanagCanvas.SetBottom(element, stanagCanvas.Height - element.Height);
      }
      else
      {
          StanagCanvas.SetTop(element, StanagCanvas.GetTop(element) + args.VerticalChange);
      }
}

I just made it to difficult and overlooked this simple sollution! Now the element stays within the bounderies of the canvas.

thx ABitSmart

ABitSmart4-Apr-09 19:42

4-Apr-09 19:42

That's great Smile | :)

Looking at your code, when it crosses the bottom boundary, you are setting the Bottom. Shouldn't it be SetTop ?

Pauwels Bart4-Apr-09 19:54

Set style definition dynamically

4-Apr-09 19:54

How could I have missed that!

WPF or Windows Forms

dfreeser1-Apr-09 12:00

dfreeser

1-Apr-09 12:00

Any insight for a small civil engineering program.

It will have 4 forms(excluding open/close dialog boxes) and will run in C#:
Main - menubar, tabstrip, Datagrid and a couple buttons
Chart Form - Graphics form to display a generated flow chart
Project form - basically a glorified dialog box for project info
Report Form - basically just a .doc file holder

If I go the WPF route I would like to produce my own style (kinda like Vista but not so heavy).

I don't have much experience with WPF besides tutorials and articles and I just want some personal experiences to help me make an informed decision.

Re: WPF or Windows Forms

Pete O'Hanlon1-Apr-09 22:03

Pete O'Hanlon

1-Apr-09 22:03

This is a fairly straightforward application, and shouldn't present you with too much trouble. If you adopt MVVM as your main design pattern, you'll find that it's easy to debug and test because you'll test your business logic in isolation from the way that it's presented.

You'll find it easier to code up a flow chart in WPF than you would in WinForms - so much of the graphics subsystem has been designed to make it easier to use (once you have experience). I would state though, that if you have experience in WinForms and none in WPF then you've got a steep learning curve ahead of you, and I'd get my feet wet on a couple of small applications first before tackling this one, so you might be better off using WinForms if that's what you're used to. If you don't have extensive experience in WinForms, I'd definitely recommend taking the plunge into WPF. Actually, I'd recommend it anyway, but I am a WPF nut.

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

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.

My blog | My articles | MoXAML PowerToys | Onyx

Re: WPF or Windows Forms

RugbyLeague2-Apr-09 5:40

RugbyLeague

2-Apr-09 5:40

If you have swear jar in your office go with WinForms - otherwise WPF is worth a go but be prepared to climb a mountain

Re: WPF or Windows Forms

dfreeser2-Apr-09 5:56

dfreeser

2-Apr-09 5:56

Thank for the responses. Ive been messing around with WPF and I feel its the way I'm going to go. I just don't like stepping into aging standards. WPF is is! I'm sure I'll be back with plenty of questions. Thanks.

salon1-Apr-09 3:46

salon

1-Apr-09 3:46

I have abutton control, there are some style properties which can be set in App.xaml like this

Style x:Key="ButtonStyle" TargetType="Button">
                <Setter Property="HorizontalAlignment" Value="Right"/>
                <Setter Property="Width" Value="50"/>
                <Setter Property="Height" Value="20"/>
                <Setter Property="VerticalAlignment" Value="Bottom"/>
                <Setter Property="Foreground" Value="Red"/>
            </Style>

and give in button control as

Style="{StaticResource ButtonStyle}"

or in xaml.cs file as

btnTest.Style = (Style)(Application.Current.Resources["ButtonStyle"]);

But I want to generate this style dynamically and save it in a string and extract the style object from that string and apply it to the Button control.
In other words I want to take style from a string not from App.xaml.
Is it possible in Silverlight 2.0?

Thanks in advance,

Re: Set style definition dynamically

Mark Salsbery1-Apr-09 7:42

Mark Salsbery

1-Apr-09 7:42

You may find the info you need in this article:

Silverlight White-labeling: "Dynamically" downloading and applying styles from a web server[^]

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: Set style definition dynamically

salon1-Apr-09 20:48

salon

1-Apr-09 20:48

I don't want to load the entire xaml file and store it.

I want this file data inside a string for example:

string s="<Style x:Key="ButtonStyle" TargetType="Button">
                <Setter Property="HorizontalAlignment" Value="Right"/>
                <Setter Property="Width" Value="50"/>
                <Setter Property="Height" Value="20"/>
                <Setter Property="VerticalAlignment" Value="Bottom"/>
                <Setter Property="Foreground" Value="Red"/>
            </Style>";

and apply that like:

btnTest.Style = (Style)(SOMETHING["ButtonStyle"]);

What will be that SOMETHING...?

How can I apply that ButtonStyle from the string s?

Re: Set style definition dynamically

Mark Salsbery2-Apr-09 5:26

Mark Salsbery

2-Apr-09 5:26

salon wrote:
I don't want to load the entire xaml file and store it.

Right. I stated the article may have the info you need.

You need a Style object from the XAML. That means the XAML has to be parsed - see the article.

What are you trying to achieve that wouldn't be simpler with a few lines of code
to create a Style dynamically?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Sys.InvalidOprationException.ManageRunTimeError error #4004 in control 'Xaml1

Piyush Vardhan Singh1-Apr-09 0:17

Piyush Vardhan Singh

1-Apr-09 0:17

hi friends
I am using sliverlight2 toolkit but it give the Error at loading time

Error:-Sys.InvalidOprationException.ManageRunTimeError error #4004 in control 'Xaml1'............................
Thanks

Piyush Vardhan Singh
p_vardhan14@rediffmail.com
http://holyschoolofvaranasi.blogspot.com
http://holytravelsofvaranasi.blogspot.com

Re: Sys.InvalidOprationException.ManageRunTimeError error #4004 in control 'Xaml1

Piyush Vardhan Singh1-Apr-09 2:02

Piyush Vardhan Singh

1-Apr-09 2:02

Problem in Control(Combobox) just delete the Item of The comboBox......................... Rose | [Rose]

Piyush Vardhan Singh
p_vardhan14@rediffmail.com
http://holyschoolofvaranasi.blogspot.com
http://holytravelsofvaranasi.blogspot.com

Horizontal scrollbar in empty listview disappears

Pankaj Chamria31-Mar-09 23:22

Pankaj Chamria

31-Mar-09 23:22

Hi,
I have a listview as below:

<br />
<Window x:Class="Practice.WPF.ListViewTest"<br />
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"<br />
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"<br />
    Title="ListViewTest" Height="300" Width="75" Closed="Window_Closed"><br />
<br />
<ListView x:Name="listView" ScrollViewer.IsDeferredScrollingEnabled="True" VirtualizingStackPanel.IsVirtualizing="True"><br />
            <ListView.View ><br />
                <GridView ><br />
                    <GridViewColumn Header="Id" DisplayMemberBinding="{Binding Path=Id}"></GridViewColumn><br />
                    <GridViewColumn Header="Name" DisplayMemberBinding="{Binding Path=Name}"></GridViewColumn><br />
                    <GridViewColumn Header="Price" DisplayMemberBinding="{Binding Path=Price}"></GridViewColumn><br />
                    <GridViewColumn Header="Date" DisplayMemberBinding="{Binding Path=Date}"><br />
</GridViewColumn><br />
                    <GridViewColumn Header="Quantity" DisplayMemberBinding="{Binding Path=Quantity}"></GridViewColumn><br />
                </GridView><br />
            </ListView.View><br />
        </ListView><br />
    </Grid><br />
</Window><br />

The problem is when there is no data bound to the listview the horizontal scrollbar disappears, and the Headers get cut off. I want the horizontal scrollbar to be still visible.
(My requirement may sound weird, but i want this functionality for a listview which displays streaming numerical data and has filters on column headers. Sometimes the filter condition does not satisfy any of the rows so the listview becomes empty and horizontal scrollbar disappears. Now some of the columns will get cut off and the user cannot scroll to that column and clear the filter.)

ANy ideas how i achieve this.

Pankaj Chamria,
Software Programmer.

Re: Horizontal scrollbar in empty listview disappears

ABitSmart1-Apr-09 1:03