I have a textblock and I would like to bind its content to a property in my viewmodel. This is fine if the content is a simple string. But it's no so fine if I want to format the content and use or tags... In this case I cannot bind a string: the textblock would simply display a string like this "Hallo".
Any ideas ? Thanks
if you have a property of some type - you can create a datatemplate for this type
<DataTemplate DataType="{x:Type local:MySomeType}">
<!--your visual presentation goes here-->
</DataTemplate>
now you can simply use a ContentPresenter to show your property
<ContentPresenter Content="{Binding MySomeTypeProperty}"/>
See what the StringFormat property can do for you. If that is not sufficient, you might want to write a binding converter.
Something like this:
<Textblock content="{Binding MyProperty, StringFormat={}Hello {1}}" />
Just got to play with the string format.
Related
I'm trying to understand. When I'm connecting View to ViewModel like this:
<DataTemplate DataType="{x:Type local:MyViewModel}">
<local:MyView />
</DataTemplate>
What does it mean?
It looks like the View is set to be the DataTemplate of the ViewModel. BUT the ViewModel doesn't have a Property of DataTemplate. So what exactly is going on in there?
A demonstration of the question - How do I do that by code (Connecting the View and ViewModel this specific way. I can't write ViewModel.DataTemplate = View)?
Thank you.
It means "To whatever control whose Content data is MyViewModel place MyView there". You are not setting DataTemplate of viewmodel (That does not mean anything) you are setting the DataTemplate for the control whose Data is MyViewModel.
Take for example an ItemsControl with an Items Source of
ObservableCollection<Employee> Employees
where each Employee is represented by a DataTemplate for Example :
<DataTemplate TargetType="{x:Type local:Employee}">
<StackPanel>
<TextBlock Text="{Binding FirstName}" />
<TextBlock Text="{Binding LastName}" />
</StackPanel>
</DataTemplate>
So in the same manner a MyViewModel.cs such as Employee.cs as a visual representation based on a DataTemplate .
and represented for example as such :
<ContentControl Content="{Binding MyViewModelProperty}" />
The way how it works is very simple. Your definition of DataTemplate is something like a definition of how a data will look like. In your example the data that you want to represent visually are of type:
DataType="{x:Type local:MyViewModel}"
By defining DataTemplate in control, window or other resources, e.g.
<UserControl.Resources> ...your template... <UserControl.Resources>,
you say "Hey, I want that all my data of type local:MyViewModel will look like this...". Inside the template you define a root control, that will be put in all places where your local:MyViewModel have been used. Normally when you place local:MyViewModel in Grid, ContentControl or other containers, you will see its string representation like "xxxx.xxxxx.MyViewModel" instead of visual.
To to see a graphical representation you must define a DataTemplate. It will replace the string "xxxx.xxxxx.MyViewModel" - representing your data and put there a visual control you defined in the template. Then when it is done, this representation - control from your DataTemplate will get DataContext property set to your View Model, here it will be local:MyViewModel instance.
That will give you a possibility to use binding in your DataTemplate, to bind in you DataTemplate directly to properties from you ViewModel.
Is that more clear now?
I can't get my custom DateTime string format to work in my binding. I want the format to be "mmmm, yyyy" (e.g. "June, 2012").
The following does not work. I get a short date format (m/d/yyyy).
<TextBlock Text="{Binding ElementName=ThisWindow,
Path=Date,
StringFormat={}{0:MMMM\, yyyy}"/>
I've considered using a converter, but I prefer a pure XAML approach.
Edit:
For clarity, I have a Window with a dependency property Date of type DateTime. In my XAML, I've named the window 'Thiswindow'.
Edit 2:
I looked back at my actual code, and I had a Label, not a TextBlock. I changed it to TextBlock and it works fine.
<Label Content="{Binding ElementName=ThisWindow,
Path=Date,
StringFormat={}{0:MMMM\, yyyy}"/>
Anyone know why it doesn't work with Label?
Thanks.
ContentControls have a ContentStringFormat property which overrides the original formatting.
(When i saw your question i expected this to be the problem actually but was surprised to find a TextBlock at first)
Your month needs to be in uppercase:
{Binding Source={x:Static sys:DateTime.Now}, StringFormat={}{0:MMMM\, yyyy}}
EDIT:
The Label problem is probably because Label has Content, not Text.
Change the Text="{Binding ...}" to Content="{Binding ...}"
I have a ComboBox in my wpf application.
It's ItemsSource is binded to some table in my DataSet.
I need the text property to be binded to another's object property . I doesn't work because the ComboBox doesn't want to get two DataContexts. How can I solve this problem?
<StackPanel Width="Auto" Height="Auto" MinWidth="296" Orientation="Vertical" x:Name="MyStackPanel">
<ComboBox x:Name="MyComboBox" ItemsSource="{Binding}" Text={Binding Path=MyProperty} />
</StackPanel>
In the code behind :
MyComboBox.DataContext = MyDataSet.Tables[MyTable];
MyStackPanel.DataContext = MyObject;
I want the ComboBox to show items from one DataContext but to show the text from another DataContext. How can I do it?
Don't use DataContext. Set the Source property of your bindings in XAML or create the bindings in code and set the Source property there.
Why are you assigning something to the datacontext of the stackpanel? From the looks of it, its not used.
Your code should work if MyDataSet.Tables[MyTable] returns an enumeration and contains a property called MyProperty.
What do you mean when you say that the combobox "doesn't want to get two DataContexts"?
Look into the properties IsEditable and IsReadOnly of the combobox.
Something like
<ComboBox x:Name="MyComboBox" ItemsSource="{Binding}" Text={Binding ElementName=MyStackPanel Path=DataContext.MyProperty} />
I'm trying to get my head around the whole MVVM thing and binding. I have a ViewModel class which has a property that is another class. I want to bind to a (string) property of that class to the text of a textblock.
I set the ViewModel as my data context for my window\page. And then do this:
<TextBlock Text="{Binding ElementName=myAddressClass, Path=StreetName}" />
But this does not work. The text is empty.
I can expose the StreetName directly as below and this works:
<TextBlock Text="{Binding Path=StreetName}" />
So am I doing something wrong in the first example. It seems simple enough ... am I just confuse about what an elementname is or should be set to?
thanks
I think you probably are confused. If you want to bind to MyAddress.StreetName, just do this: Text="{Binding MyAddress.StreetName}" Make sure MyAddress is a property of your DataContext. ElementName is for binding to other controls.
ElementName is used to reference a XAML element in the Logical Tree. Since what you're trying to bind to is not an element, ElementName isn't the correct approach. Dotted path notation is the simplest approach in this case:
{Binding Path=myAddressClass.StreetName}
In the below code, Combobox is wired to NameInfo object along with a converter.NameInfoConverter returns a format in which items in combobox are shown in a particular format (for eg: LastName, FirstName (Badge#) )
Now, when I set TextSearch.Text="{Binding NameInfo, Converter={StaticResource NameInfoConverter}, ConverterParameter=true}" on combobox; TextSearch doesn't work. When I set TextSearch.TextPath="Name", search itself works but doesnot get the correct format displayed in the selectionbox of combobox.
Any Ideas?
<StackPanel>
<ComboBox x:Name:"cmbName">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name,
Converter={StaticResource NameInfoConverter}, ConverterParameter=true}"/>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
</StackPanel>
You've probably hit a limitation in the API. I suggest you take an alternative route and bind directly to a property that is correctly formatted for your textblock.
If this is a serious app, you may want to look into using the MVVM pattern and place your converted/formatted property in the viewmodel. Otherwise, just create a new property on your databound class called NameInfo or something and do the conversion from that.