In a WPF Custom Control template, is there any way that I can do the following in XAML?:
var selItemText = this.GetTemplateChild("PART_SelectedItemText") as TextBlock;
var binding = new Binding("SelectedItem." + DisplayMemberPath);
binding.RelativeSource = new RelativeSource(RelativeSourceMode.TemplatedParent);
selItemText .SetBinding(TextBlock.TextProperty, binding);
Note that the interesting part of this statement is the binding constructor - I am building up a path based on both some text I specify ("SelectedItem."), and the path provided by the user.
The consumer would use the control similar to:
<c:MyControl DisplayMemberPath="Description" />
short answer: no, it's not possible to get this entirely in xaml within the controltemplate
your possibilities are:
use what you have (possibly using attached properties / a behavior to make it more MVVM-like)
use a MultiBinding one binding to the "SelectedItem" the other to "DisplayMemberPath" and your MultiValueConverter using Reflection to reflect down the DisplayMemberPath (may be a bit ugly)
create a class that inherits from Binding and exposes Properties that you can bind the DisplayMemberPath to and changes the underlying Binding (read here for how you can do this) (complicated)
use Reflection to instantiate a MS.Internal.Data.DisplayMemberTemplateSelector / build something similar
think about if your design is right. Other than your Control being some kind of ItemsControl (if that was the case you should inherit from ItemsControl and use the DisplayMemberPath you get there), I don't see why you shouldn't use a Binding on the outside like <c:MyControl DisplayMember="{Binding SelectedItem.Description}" /> and in your ControlTemplate use a TemplateBinding to bind to "DisplayMember"
You can split it to two different bindings. Have SelectedItem binds to a toplevel control of TextBlock and TextBox.Text bind to DisplayMemberPath as TemplateBinding.
Related
I'm trying to bind combobox editor in a PropertyGrid to a list.
<dxprg:PropertyGridControl SelectedObject="{Binding SelectedEmployee}">
<dxprg:PropertyDefinition Path="EmployeeCountryID">
<dxprg:PropertyDefinition.EditSettings>
<dxe:ComboBoxEditSettings
ItemsSource="{Binding Path=DataContext.Countries, ElementName=rootWindow}"
ValueMember="CountryId" DisplayMember="CountryName" />
</dxprg:PropertyDefinition.EditSettings>
</dxprg:PropertyDefinition>
</dxprg:PropertyGridControl>
This example is from a third-party control but the problem may be just general.
The "rootWindow" DataContext has been set to a ViewModel which holds a property List(of Country) that I want have as ItemsSource in a Combobox.
I was trying to access that list by setting the Combobox ItemsSource to the rootWindow.DataContext.Countries property but I don't get any data.
Tried also all those RelativeSource FindAncestor bindings but no data appeared either.
Why can't I bind through a DataContext of a given element like this?
This became solved. The problem was not with the binding at all but realated to how I defined the third-party control: Instead of EditSettings I should have defined CellTemplate -> DataTemplate.
I am building a WPF application and I have some DependencyProperties in my window's codebehind (actually a big bunch of them). I want to bind a textbox to one of these string values. If I use {Binding ObjectName} it just doesn't work and it complains about not finding the property in the output. If I use {Binding ObjectName, ElementName=window} (where window is my Window's instance name), it works. But I have lots of bindings and I don't want to use the ElementName property each time. Is there any shortcut that will default all the element names to the window objects, as all of my bindings have the same element?
Thanks,
Can.
The default source of a binding is FrameworkElement.DataContext so you have to set the DataContext property of your window to the instance of your window e.g. DataContext = this;
I implemented some generic CustomControls in WPF, for instance an AutoCompleteTextBox.
Now, I'd like to implement a generic ViewModel library, in order to perform the databind of these controls.
Now I defined one attached property named CDataSource, that specifies the source of the data to bind within the control.
My question is : Is it possible, that the CustomControl passes to the ViewModel the CDataSource value? In this way the ViewModel may populate the control on the basis of the CDataSource property.
Thanks in advance
This seems like a strange request to me. You don't want any dependency on your view model from within your custom control. Instead, you would normally have a dependency property on your custom control which is the ItemsSource, and then you would set the value of this from your view in XAML.
This is how the AutoCompleteBox included in the WPF Toolkit operates.
I'm creating a WPF custom control as an auto learning exercise. My control has a ListView inside the template. I wanto my control user be able on defining the needed columns in his own Xaml, but I did not get the strategy on how to pass the columns to the inner listview since binding with FindAncestor complain that "Columns" is not a DependencyProperty.
Wekk the questions are:
How to achieve bind a property from xaml to the template when it is not a DP
Correct my design: I think there is something wrong: if someone would change completely my template, how should I let him use the Column collection ?
why not inherit from ListView directly? Then you have all the properties you need for the ListView and can also add you own properties to the class.
Then you can apply a custom Style to your control to make it look like you want. (Here you have a basic ListView Style that you can use and expand to your needs)
Sometimes binding to a property that is not a dependency property can be solved using the Binding Mode OneWayToSource
Have you tried that?
HI Can any one suggest me how bind viewmodel to a usercontrol..
Also please share different way of doing that..
I have added viewmodel and view into my xaml file in namespace and in the user control resource tag.. i have defined a data template with data type as the viewmodel wh i have wrote.. inside that i have added my view (i mean the same usercontrol ih which im editing now is it possible -- please let me know).. I have used content control with content={Binding}.. and contenttemplate as a datatemplate.. in that i have reffered the property which i want to bind from viewmodel).. but its not binding as such..
My query is different ways of binding viewmodel to view in UserControlLibrary Project ?
Sdry's right, you can also set the DataContext property of your view to your ViewModel.
Also, here's a WPF databinding cheat sheet that will likely come in handy: http://www.nbdtech.com/Free/WpfBinding.pdf
Set the datacontext of your view, with an instance of your viewmodel. Throughout your view you can then bind to the properties of your viewmodel with "Path" in the binding.