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Give a man a fish, and he'll eat for a day.
Turn a man into a fish, and he'll be eaten for the rest of his life.
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In a SL 3 C# app there is a page named MainPage that contains a TabControl with some TabItems.
In the Page_Load event a user control is instantiated and added inside the MainPage's first TabItem.
For the sake of simplicity, the user control has only one button. I want to click this button and change the selected index of the TabControl .How?
To access the TabControl inside the MainPage directly I will need to create a static method but it will require the tabControls to be static as well and I definitely don't want to do that (Don't even know how).
Can someone show an example on how to access the MainPage's TabControl from inside the user control?
Thanks a lot!
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I personally don't think a usercontrol should have intimate knowledge
of its parent tree so I would go with a different design - perhaps
add an event to the usercontrol that is raised when the button is clicked.
The parent of the usercontrol could subscribe to this event and handle the
tabcontrol appropriately.
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://www.codeproject.com/script/Forums/Images/coffee.gif)
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Thanks Mark.
Would it be possible to post an example in C# 3.0 ? I have googled Delegate events but it has not been easy to find a good article about.
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My previous question concerned dragging and dropping into a ListBox and the answer was in the Drop event I had to execute code like this:
Array a = (Array)e.Data.GetData(DataFormats.FileDrop);
The other part of this is that I have to set the AllowDrop property to true on the ListBox. All that works fine.
But then when we come to a TextBox, setting AllowDrop to True doesn't work. I drag text into the field and the cursor with the red slash through it persists when it enters the TextBox! I noticed the same thing months ago, but was busy with other things, so dropped the attempt to get dragging and dropping working into a TextBox. But when I got it working with a ListBox, I figured I now knew enough to get it working with a TextBox. No such luck! What am I missing?
Addendum: I just read that the WPF TextBox has drag and drop by default, and indeed dragging from one TextBox to another does work by default. But dragging and dropping from Windows Explorer to a WPF TextBox does not work whether or not AllowDrop is set to true, and that's precisely what I need. How can I get it?
modified on Friday, September 25, 2009 12:06 PM
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As you have found, the TextBox (as well as RichTextBox and FlowDocument) marks drag and drop events as handled, which causes you real problems in cases like this. At first, you might think that this leaves you with a problem, but rejoice - WPF provides you with all that you need to do what you want.
The first thing that you need to do is modify the textbox to use certain preview events (PreviewDragEnter, PreviewDragOver and PreviewDragDrop) like so:
<TextBox
AllowDrop="True"
PreviewDragEnter="TextBox_PreviewDragOver" <-- Notice how this event
PreviewDragOver="TextBox_PreviewDragOver" <-- and this one map to the same event handler.
PreviewDrop="TextBox_PreviewDrop"/>Then, all you need to do is add the code for the events in the code behind:
private void TextBox_PreviewDragOver(object sender, DragEventArgs e)
{
e.Effects = DragDropEffects.All;
e.Handled = true;
}
private void TextBox_PreviewDrop(object sender, DragEventArgs e)
{
object text = e.Data.GetData(DataFormats.FileDrop);
TextBox tb = sender as TextBox;
if (tb != null)
{
tb.Text = string.Format("{0}",((string[])text)[0]);
}
}This sample simply picks the filename out and writes it to the textbox - you can do it with whatever you want. There, I hope that helps.
"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
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Excellent! I already had about 100 edit boxes scattered throughout my app that requires file paths and they all called a custom control I wrote, so modifying that single custom control got them all accepting drag and drop in five minutes!
I do wonder how people like you find answers like this. For example, where did you learn that you had to code those PreviewDrag events? And why do you use the PreviewDrop event and not just the Drop event? And what learning experience did you have to go through to realize that? What I'm trying to learn is the basis of your knowledge, because there's so many things about WPF that I don't seem to be able to figure out off the top of my head and have to Google for the answer, and my WPF app now has over 70,000 lines of C#/XAML code in it, which I've spent nine intense months developing (60+ hours per week). You'd think by now I'd be able to do it all, but I'm still puzzled by problems that crop up left and right. My work habits must be deficient in some way.
A specific question I have about your solution is that you get the standard mouse cursor with the plus sign inside a box when the drag operation enters the edit box. In my initial solution to the drop into a ListBox I got a mouse cursor with an empty box, not the box with the plus sign. By experimenting I determined that you achieve this with the code you have in the PreviewDrag events. What about that code gets you the cursor with the plus sign, avoiding that anemic cursor without the plus sign?
modified on Saturday, September 26, 2009 11:00 AM
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fjparisIII wrote: What I'm trying to learn is the basis of your knowledge, because there's so many things about WPF that I don't seem to be able to figure out off the top of my head and have to Google for the answer, and my WPF app now has over 70,000 lines of C#/XAML code in it, which I've spent nine intense months developing (60+ hours per week). You'd think by now I'd be able to do it all, but I'm still puzzled by problems that crop up left and right. My work habits must be deficient in some way.
I'm lucky enough to be in regular contact and conversation with the likes of Josh Smith, Karl Shifflett, Sacha Barber and the likes through the WPF Disciples. It's not that your work habits are deficient - rather that the Disciples, eat, sleep and breathe WPF which means that you really start to investigate/think about the internals in depth. I've spent 2 years now, learning WPF to quite some degree, and at times I spend up to 100 hours a week working in WPF - I do it at work, and then go home and do it some more. This is just because the conversations we have in the Disciples can be so interesting, that intellectually you just don't want to give up.
Anyway, to answer your other question, I wrote a blog entry here[^] that might go some way towards answering your queries about the mouse cursor.
"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
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Thanks very much for your reply. It explains a lot, and now I don't feel so inadequate. I have several books I consult, in addition to Googling all the time for answers and scouring MSDN and am still constantly blocked in my understanding of this and that within WPF. Also I've only been "at" this WPF thing for about a year (after doing C++/MFC since 1992 and STL since 2001).
Is there any way an outsider like myself can at least "listen in" on the conversations of the "Disciples"? Or is this some kind of private club for the "elite"?
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fjparisIII wrote: Is there any way an outsider like myself can at least "listen in" on the conversations of the "Disciples"? Or is this some kind of private club for the "elite"?
If it were only for the elite, then I wouldn't be in it.  It's a Google groups list, and you can find it here[^]. There's no reason to feel inadequate - a lot of the knowledge comes about the old fashioned way, discussing it with others and knocking the rough edges off ideas between yourselves.
If you're serious about WPF (and possibly Silverlight), you owe it to yourself to start looking into MVVM. Honestly, this pattern (while looking really confusing at first glance), simplifies a lot of what you can do in WPF. A lot of time, I don't bother with Attached Properties or Routed Events, I use MVVM and POCO (that's plain old clr objects), and it just fits into place.
"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
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I put my bid in to join the Disciples. Sounds like just the ticket for me.
I am interested in Silverlight, but I hardly even qualify as a beginner in Web development, even though I desperately need to develop some skills in it. I'm in the middle of reading one book on Silverlight, have ordered Matthew McDonald's yet to be published book on it, and so far am completely mystified about how it ties in with HTML. If I developed a Silverlight application, I wouldn't even know what to do with it.
But I recently bought Microsoft Expression Web 3 and that has some things in it about connecting to Silverlight applications. Maybe it will throw some light my way. Expression Blend is a little too pricy for my means.
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Hi,
I have created a WPF IpAddressTextBox that inherits from System.Windows.Controls.Textbox. I want to initialize the textbox with the string " . . . " when the application starts.
Everything works fine if I add the textbox to a testproject with the .xaml file with
<local:IpNumberTextbox Width="200" Margin="5"/>
But in the real project I add the textBox with
<controls:IpNumberTextbox Width="100" Text="{Binding SelectedItem.DNS1, ElementName = profilList }" />
In this project I have a Binding and when the dialogs shows up the textBox contains "" instead of
" . . . ". In the debugger I can see that the TextBox Text property contains
" . . . ", but the GUI is not updated. Why?
Regards
Marcus
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I would like to accept what is dropped from a drag operation of a selection of paths from Windows Explorer into a ListBox. I would think this would be pretty simple to do, but I can't find any examples that show how to do it. In my Drop event in the ListBox I have this line:
object text = e.Data.GetData(DataFormats.Text);
text comes back as null. How would I get at the list of files and folders dragged from Windows Explorer?
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Try DataFormats.FileDrop, which will yield a string array of file names.
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Thanks. After making my original post, shortly thereafter I did one more Google search and found the answer, but was still curious whether anyone would answer me so didn't mention it.
I was specifically interested in getting an array of file folders, since I can already get an array of file names with the normal WPF file browser, but can't get an array of file folders with the Shell's Folder Browser. Drag and Drop (and probably copy and paste) are the only ways to do that.
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We have a wpf app developed under windows XP SP2. When this app runs under Vista, the text gets clipped in many places - it is as though a different font is used which is slightly larger.
I have seen this with both Tahoma and Arial.
I could go through and add padding or miniumum height to solve the, but it seems as though that should not be necessary (and may lead to other problems).
Has anyone else experienced this? Can anyone provide some advice or pointers?
A sample style is as follows:
<Style x:Key="Heading3" TargetType="{x:Type TextBlock}">
<Setter Property="FontWeight" Value="Bold"/>
<Setter Property="Foreground" Value="{DynamicResource textDimmedForegroundBrush}" />
<Setter Property="HorizontalAlignment" Value="Left" />
<Setter Property="FontFamily" Value="Arial"/>
</Style>
Thanks for any help,
Tim
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I've had this happen, it's a real PITA. i suspect you can get around it by making sure you set the font size explicitly, but even then, I think the best thing to do is to make sure you test on both and that you provide space for both.
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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Hello
I am having difficulty finding an article / tutorial on how to create a custom control that derives from System.Windows.Controls.Control class using a ControlTemplate to display visuals.
I find most of my search queries just return results for UserControl or deriving from another class (TextBox etc).
Could someone please provide me a link if they know of one.
Thank you.
-Mike
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This[^] may go some way towards what you are looking for. I would also suggest any other articles by the author, Sacha Barber, or alternatively, Josh Smith. Further, both these legends provide links to other authors who they recommend, which is in itself the best recommendation you are likely to see.
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Thanks Richard, but not quite what I am looking for.
The control I am currently working on originated as a derived class of System.Windows.Controls.Panel. I got this to a point where I was happy with measure and arrange overrides of child objects. I wanted this container/panel to have a visual style to be applied to it, as well as the option to create alternate control templates. I changed the derived class from System.Windows.Controls.Panel to System.Windows.Controls.Control . At this point I lost the rendering of my control.
I am looking for some information on how to get the rendering of this object back, also how to set a control template for it.
Do I need to override any rendering code when working with a base class of System.Windows.Controls.Control?
I have tried to use a control template in the way I would have used it for a control derived off another base class eg.
SearchTextBox : TextBox
DefaultStyleKeyProperty.OverrideMetadata(typeof(SearchTextBox), new FrameworkPropertyMetadata(typeof(SearchTextBox)));
CustomControl : Control
DefaultStyleKeyProperty.OverrideMetadata(typeof(CustomControl), new FrameworkPropertyMetadata(typeof(CustomControl)));
When I try to view this template in Blend I get the following error.
Unable to cast object of type 'Microsoft.Expression.DesignSurface.ArtboardBorder' to type 'ParentOfCustomControl'
(The custom control has a fixed Parent type which is derived from System.Windows.Controls.Grid)
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Sorry Mikey, but you have me there. I only posted the link to you because it was something I had previously used and thought it fitted what you were looking for. As for Blend, it's not a product I have had experience of.
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Hi.
I have the following code in a WPF Application :
<br />
<br />
<Window x:Class="WpfApplication1.Window1"<br />
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"<br />
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"<br />
Title="Window1" Height="300" Width="300"><br />
<Grid><br />
<ListView Name="listView1" Margin="11.5,7,10.5,19.5"><br />
<ListView.View><br />
<GridView ><br />
<GridViewColumn Header="1"/><br />
<GridViewColumn Header="2"/><br />
</GridView><br />
</ListView.View><br />
<br />
</ListView><br />
</Grid><br />
</Window><br />
<br />
But in designer i see the listview empty and i dont see the 2 columns. I only see them on runtime.
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I copied your code as it is in to a new WPF Project and I had no problems at all i.e. the columns were visible in designer.
I use VS2008(SP1).
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Ok.
It seems that an update to sp1 was required.
Thanks.
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