It's hard for me to clearly describe my problem but I'll try. I have a UserControl1 which contains UserControl2 which contains several WinForms controls (most of them DevExpress). I do simple binding to these controls to my datatable fields. So far everything works fine. When I move the focus to a record in the table (by navigating in a grid rows for example) the binding works great, the concurrenmcy manager moves the cursor and everything reflects right in the bounded controls.
The problem starts when I add new user UserControl3 above UserControl2 and make UserControl2.Visible = false. Now UserControl3 is shown and UserControl2 exists but not shown. Now when I set UserControl2.Visible = true to show it again the simple binding stops working! I navigate in the grid but either the ConcurrencyManager stops working or the simple binding becomes disconnected.
My question: Are there any known issues/ best practices with the binding & concurrency manager?
Thanks a lot,
Adi Barda
I found the answer. The guys from devexpress helped me and now I know that in order to succeed with binding one should use the BindingSource object and not use directly the dataset/datatable objects. This solved all my binding problems. I beleive the BindingSource simply working correctly with the concurrency manager and the bindingContext objects.
Related
I am going crazy trying to figure out how to manipulate telerik RadGridView for WPF's column filtering from my ViewModel. I thought I might be able to bind the value of a FilterDescriptor to a ViewModel property, but I get
Cannot find governing FrameworkElement or FrameworkContentElement for target element
<telerik:CompositeFilterDescriptor>
<telerik:FilterDescriptor Member="Foo.SomeProperty" Operator="IsContainedIn" Value="{Binding SelectedThings}" />
</telerik:CompositeFilterDescriptor>
where Foo.SomeProperty is a VM property bound to a grid column and SelectedThings is a VM property containing a stringified array of unique values to filter against.
GridView is bound to a QueryableCollectionView.
I want the filtering to work at runtime, based upon some custom logic in the VM - ex. user clicks some button and the VM restricts distinct values of one of the columns.
This shouldn't be so hard. I must be approaching this wrong. I've been pooring over other stackoverflow questions but haven't found a solution that works yet. Any suggestions would be appreciated.
UPDATE
I would still like to achieve this with a completely MVVM approach, but for the time being I've decided to stop going nuts over it and resolve the issue in the following way.
ViewModel's ObservableCollection which is bound to a list of checkboxes representing some filtering criteria are updated by the user through the GUI.
Upon that property change the ViewModel sends a message via Messenger (MVVMLIGHT) which in the codebehind has registered to receive. The message includes the filtering criteria information.
The codebehind receives it and applies it directly to the GridView.
What's nice about this is it avoids having to wire up any DependencyProperties or other event handlers and allows the VM to remain ignorant of the View implementation. It's simple and it works.
Yes, there's a little code behind now, but until I can find some better info on how to solve this problem purely through MVVM binding, this is a workable solution.
Wish I'd done this at 9 AM yesterday instead of banging my head against the wall all day long reading Telerik's crappy documentation and hunting for examples of how to do it "the right way". Meh.
I've been creating an inspection form using WPF and I need a place where users can type an unknown amount of comments (hence why I'm not using textboxes). In my WinForms version of this application, I used a DataGridView and I could enter in as much information as I wanted to. I'm looking to do the same with a DataGrid or an equivalent control in WPF.
WinForms Example
I need to be able to do the same thing in WPF but I can't seem to add any rows in the DataGrid. On top of that, when I try to check CanUserAddRows it unchecks it immediatly.
So I checked out Vincent Sigal's blog post about this issue. He mentions something interesting:
... but beware of CanUserAddRows and CanUserDeleteRows as they can appear a little magical. Their values are coerced based on other properties such as DataGrid.IsReadOnly, DataGrid.IsEnabled, IEditableCollectionView.CanAddNew, and IEditableCollectionView.CanRemove. So this is another thing to watch out for when editing. If you run into a situation where you set CanUserAddRows or CanUserDeleteRows to true but it is changed to false automatically, check that the conditions below are met.
I verified this and my DataGrid is not read-only and it is enabled. Although, I have no idea where to find the IEditableCollectionView.CanAddNew and IEditableCollectionView.CanRemove ...
I don't think my situation should require a binding event on the DataGrid since the user is supposed to enter his comments directly into the DataGrid ... Is what I'm trying to do even possible? Perhaps I should use a different control?
I have to admit that I stopped reading through your question after the first paragraph, so please forgive me if I have understood you wrong... but if you just want to enter multi line text into a TextBox in WPF, you can do it by setting a couple of properties on it:
<TextBox TextWrapping="Wrap" AcceptsReturn="True" />
For a DataGrid, you can set these properties in the DataGridTextColumn.ElementStyle and/or DataGridTextColumn.EditingElementStyle as the WPF DataGridTextColumn multi-line input post shows quite nicely.
Please let me know if I did misunderstand you.
UPDATE >>>
Ok, so I came back to read the rest of your question... answering without reading the question can be risky business on this site. It's just as well that I did too, as I see you also want to know how to use the DataGrid.
I have to start by saying... take a deep breath... WPF is very different to WinForms... very different. In WPF we manipulate data rather than UI objects, so to add a new row actually means adding a new item to a collection. You can find a complete working example on the DataGrid Class page on MSDN.
Please also view the WPF DataGrid Control page on WPF Tutorial.NET for more examples. WPF has a lot to take in for new comers and can be quite bewildering, but it's well worth the trouble when you get into it.
I've got a new Problem here. I've got a MainWindow in which is a ContentGrid and in this is a Frame. Now I've created different Pages which can be shown in this "content-area". In One of these pages there is a Datagrid bound to a CollectionViewSource which Source is a Database (via EntityFramework). Now, when a Change on this Database-Table happens (solved via ServiceBroker and SQLDependency, firing works fine) The Datagrid have to update.
Now the Problem:
The "Dependency_OnChange"-Event is working in the MainWindow-Thread. When i try to access the CollectionViewSource of the Page to Update it (cvs.View.Refresh) i get an Exception that this is not possible because of another Thread which own this CVS.
I've tried it with different Dispatching like:
Application.Current.Dispatcher.Invoke((Action)(()=>
{
cvs.Source = _db.Table.OrderByDescending(nr => nr.Date).Take(200);
cvs.View.Refresh();
}));
This Codeblock doesn't brings an Exception but i wont update the UI too... It seems that it does nothing.
Can anyone help me?
You data grid will update if your LINQ query evaluates. Right now it just specifies the LINQ IEnumerable but is not evaluating it.
cvs.Source = _db.Table.OrderByDescending(nr => nr.Date).Take(200).ToList();
should do the evaluation of the LINQ for you...
Although I must say your cvs.View.Refresh() call is very expensive as it causes entire grid to refresh. You may have to consider a better design here.
Why dont you set the dataGrid.ItemsSource = _db.Table.DefaultView as the item source to the datagrid directly. I guess if your table updates (and peforms _db.Table.AcceptChanges();) the view would automatically notify the changes to the grid and grid would possibly update itself faster!
But thats just my opinion as I am not aware of your threading context here. But still do try and let me know.
Could anyone answer a really frustrating newbie question please?! I've been hunting for an answer for a few days & have found answers to similar questions posed, but nothing that exactly solves my issue.
I'm trying to bind a textbox to the currently selected item in a listview (which itself is bound to an Observablecollection of objects, not sure if this matters).
The listview is in RecentEntities.xaml & the textbox is in Relationship.xaml, both of which are positioned on the Main Window from within Maincontrol.xaml. So they're in the same namespace but they're in different pages so using ElementName doesn't work as this just seems to look within the current page.
The issue I'm having is when trying to define the source of the textbox binding in Relationship.xaml, how do I reference the selected listview item in RecentEntities.xaml? I wondered about using RelativeSource, but this seems to only let you navigate up the tree to an ancestor of the current control. Because of how MainControl is set up, I would need to travel up to the parent of the textbox, then to a sibling of the parent then down to a child of a child of it in order to get to the listview!
I've explored (possibly not in enough depth) other options like resources, data context, including header files and have read something about Merged Resource Dictionaries but to be honest the more possibilities I explore, the more confused I'm getting about what I need to be doing.
Is this really as complicated as it seems?! Any pointers or help would be brilliant, thanks for taking the time to answer :) I haven't posted on here before, so if you need any code snippets please let me know.
Can you create a ViewModel that both Views will use? Have the selected item in your listview bind to a property in the ViewModel and have the textbox bind to the same property. As long as both views reference the same instance of the viewmodel, it should work.
With two XAML files you will have to use the model or viewmodel (depending on your choice of architecture) for synchronization.
For the listview you can use the SelectedValue to bind to a property, use Mode=OneWayToSource for this binding since you just want to update the property, not change the selection in the listview itself.
I am eager to find some solid (free, Open Source, or tutorial/example) code to make a WPF Combobox do autocomlete/autofilter as the user types. But everything I've tried so far has had some sort of problem...
A Reusable WPF Autocomplete TextBox came close, but I can't get it to work with more than one filter (more info here).
WPF autocomplete textbox/combobox doesn't work for me because it inherits from UserControl, and thus doesn't support the DataTemplates I need (for showing/selecting the value of one property for an object with multiple properties).
Automatically Filtering a ComboBox in WPF didn't work because it doesn't seem to ever find the EditableTextBox portion of the inherited ComboBox code (via (TextBox)base.GetTemplateChild("PART_EditableTextBox") which seems to always returns null).
Building a Filtered ComboBox for WPF just gets stuck in a refresh loop then overflows the stack after I type just a few letters.
Other things I've considered:
I know that Windows Forms' Combobox control has AutoCompleteMode and I could embed it in WPF, but I can't imagine it would play very well with my WPF data bindings.
Perhaps it is too complex and I need to simplify, maybe by building one-dimensional (single-property) ObservableCollections for the ComboBoxen... However, the challenge of applying multiple filters (one set by another control's value, and one from what the user is typing) to multiple controls using different views of the same DataSet would require a ridiculous amount of processing power to destroy and rebuild the list every time the user types a character!
So... I'm at wit's end. Any suggestions?
If your Combobox has some data source attached to it ,
just make
1-IsTextSearchEnabled = true.
2-IsEditable = true.
you are good to go
Try this one:
http://blogs.windowsclient.net/dragonz/archive/2010/02/23/autocomplete-textbox-control-for-wpf.aspx