I have the following Xaml for a grid and I want to be able to modify the value of the Content in code. I want to depending on the condition, not display the "[+]". How do I do that. Also how do i trigger an event to make the change. I am using an Infragistic XamGrid but I think it will apply to other grids too.
<ig:UnboundColumn Key="Sel" x:Name="ubcSel" IsFixed="Left" Width="44" HeaderText=" " PropertyChanged="UnboundColumn_PropertyChanged">
<ig:UnboundColumn.ItemTemplate>
<DataTemplate>
<HyperlinkButton Name="hblSel" Click="hblSel_Click"
Content="[+]" FontWeight="Bold" FontSize="12" HorizontalAlignment="Center" />
</DataTemplate>
</ig:UnboundColumn.ItemTemplate>
</ig:UnboundColumn>
Why don't you use binding on the content property and place the conditional logic in an exposed ViewModel property?
Related
In my WPF view, I need something similar to an Expander or a TreeView, but instead of completely hiding the content, I only want to hide empty parts, i.e. TextBoxes with null or empty text, or empty ItemCollections.
I thought about using a style with a DataTrigger or set Visibility with a converter, but how would I link that to the parent's setting (e.g. IsExpanded)?
I would like to avoid doing this in the ViewModel, as that would need a property for each section (and I need lots of them), but it's purely visual and therefore IMHO it only belongs to the View.
So I guess the way to go is to use DependencyProperties or write some CustomControls, but I don't have an idea where to start. The XAML of the end result could look something like this:
<CustomExpander Header="Main" CollapseContentIfEmpty="True">
<CustomExpander Header="Section1" CollapseContentIfEmpty="True">
<StackPanel>
<TextBox Text="{Binding SomeString}" />
<TextBox Text="{Binding SomeEmptyString}" />
</StackPanel>
</CustomExpander>
<CustomExpander Header="Section2" CollapseContentIfEmpty="True">
<ListView ItemsSource="{Binding SomeCollectionView}" />
</CustomExpander>
</CustomExpander>
In this example, if CollapseContentIfEmpty is set to true and the CollectionView shows no elements (e.g. due to filters), only the content of SomeString should be visible, along with all the headers. If SomeString is empty, only "Main" should be visible, as now all child CustomExpanders are empty as well.
Setting CollapseContentIfEmpty to false (e.g. via a Button like in Expander) would show all Children again, regardless if they are empty or not.
I thought about using a style with a DataTrigger or set Visibility with a converter, but how would I link that to the parent's setting (e.g. IsExpanded)?
Use a binding with a {RelativeSource}.
In the following example, the TextBlock is invisible unless you set the Tag property of the parent UserControl to true:
<UserControl xmlns:sys="clr-namespace:System;assembly=mscorlib">
<UserControl.Tag>
<sys:Boolean>false</sys:Boolean>
</UserControl.Tag>
<UserControl.Resources>
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />
</UserControl.Resources>
<StackPanel>
<TextBlock Text="text..."
Visibility="{Binding Tag,
RelativeSource={RelativeSource AncestorType=UserControl},
Converter={StaticResource BooleanToVisibilityConverter}}" />
</StackPanel>
</UserControl>
You can of course replace the UserControl with a custom control with a custom bool property.
An Expander collapses its entire Content which is different from hiding specific controls in that content.
I have XAML:
<TextBlock Text="Param 1 name" Margin="6,6,0,0"></TextBlock>
<TextBox Text="{Binding Param1Value, UpdateSourceTrigger=PropertyChanged}" Margin="6,6,0,0"></TextBox>
<TextBlock Text="Param 2 name" Margin="6,6,0,0"></TextBlock>
<TextBox Text="{Binding Param2Value, UpdateSourceTrigger=PropertyChanged}" Margin="6,6,0,0"></TextBox>
...
<TextBlock Text="Param N name" Margin="6,6,0,0"></TextBlock>
<TextBox Text="{Binding ParamNValue, UpdateSourceTrigger=PropertyChanged}" Margin="6,6,0,0"></TextBox>
How can be optimized this code to prevent copy-paste?
Control, Style, ContentControl or DataTemplate?
I can use Style to reuse margin, but how can be reused structure of this pairs TexBlock and TextBox?
Make a UserControl with two properties (E.g., Caption and Text) and bind the TextBlock to the Caption and the TextBox to the Text property.
You could also use a Templated Control if you want to allow the designer to create a custom templates so he can fully control the UI design.
UserControl vs. Custom/Templated Control (read the entire thread for maximum benefit):
Well the difference between user control and custom control is that If
you have a portion of views or UI which will be used repeatedly in
your own project, using UserControl is a much simpler and preferred
way, but if you have a portion of UI and functionality which you
believe will be used aross different projects, then using custom
control is the right approach.
May be you should try an ItemsControl Class and set it's DataTemplate.
I have many FrameworkElements (TextBlock, CheckBox, ListBox..) and I would like to make something allowing me to show a small number besides every one control.
Some text ³
I came with the idea to write a MarkupExtension, where I could write that number like this:
..
<TextBlock Text="Some Text" SomeExtension="3" />
..
and then to add it somehow to the template of the Control.
But I'm sure, you guys have better solution for this problem ;)
One way to go with it would be create a Attached Property. Upon setting it on a control, a custom Adorner would be added for that control showing specified number.
Use the tag property to provide the number you want and inside the custom template databind to the property
<TextBlock Text="Some Text" Tag="3" />
and inside the controltemplate
<TextBlock Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Tag}"/>
I have an ObservableCollection of addresses that I am binding to a ListBox. Then in the ItemTemplate I am Binding to the current address record using {Binding .}. This results in my addresses displaying using their ToString method which I have setup to format the address. All is good, except if I update properties on an individual address record the list in the UI does not update. Adds/Deletes to the list do update the UI (using the ObservableCollection behavior). If I bind directly to properties on the address the UI does update (using the INotifyPropertyChanged behavior of the Address object).
My question is, is there a way to notify the UI of the change to the object as a whole so that I can still use this syntax or do I need to punt and put a DisplayText property on my address type that calls the ToString method and bind to that? FYI, this is an MVVM architecture so I don't have the luxury of calling Refresh on the ListBox directly.
Thanks for any help/ideas.
<ListBox x:Name="AddressList" ItemsSource="{Binding Addresses}" Background="Transparent" BorderBrush="Transparent"
Width="200" HorizontalAlignment="Left">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding .}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
When you bind to the Address object itself, the object itself -- that is, its identity -- doesn't change, even though its properties do. WPF therefore doesn't know to refresh the binding in this case.
So yes, you need to bind to a notifying property (or properties) rather than the whole object. As you say, one way to do this is to create a DisplayText property, and raise the PropertyChanged event for that property whenever something that affects the display text changes. Another is to use multiple TextBlocks in a horizontally oriented StackPanel, each bound to a particular property e.g.
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding HouseNumber}" />
<TextBlock Text=", " />
<TextBlock Text="{Binding Street}" />
<TextBlock Text=", " />
<TextBlock Text="{Binding City}" />
</StackPanel>
The advantage of the second approach is that it gives you flexibility in the UI to change how addresses are displayed, e.g. multiple lines, formatting, etc.; the downside is that it gets complicated if you have conditional logic e.g. an optional flat number or second address line.
I tried to reproduce the problem and succeeded.
I activated the step-into-.NET debugging options, and saw that WPF does not listen to INotifyPropertyChanged if the path in the binding is empty.
What worked to get a change to be reflected in the list box is to replace the whole object in the ObservableCollection. This triggers the INotifyCollectionChanged, with the Replace action.
But this may not be acceptable in your case. And it could be seen more like a hack than a solid solution.
I'd seriously consider having a DataTemplate for Address. There you should bind to the exact properties you need (which would create the listener for INotifyPropertyChanged). It is more flexible than ToString() and you may encounter cases where you have a need for ToString() to do something for non-UI stuff, which would create a conflict. And honestly, ToString is not really meant for UI stuff.
I have the following code and basically what i am not able to figure out is how to clone the whole grid and make a blank copy of them side by side.... for a clear understanding this is something to do with hospital application and the grid is related to a pregnancy so when said 'ADD CHILD' button a whole new grid should be created during run time, thanks for the help below is a link that might help people cause i tried it but not sure how to display it
How can you clone a WPF object?
You should put the object you are want to "clone" in a DataTemplate and reference this template from an ItemsControl, then when you need another grid add another item to the items control (or even better to the list the control is bound to) and the ItemsControl will create a new grid and bind it the new object.
For an example take a look at this post on my blog.
Here is an example for this application (I left only the relevant parts and I didn't test it, so there are probably some typos there):
<Window ... >
<Window.Resources>
<DataTemplate x:Key="ChildTemplate">
<Grid>
...
<TextBlock Text="Delivery Date:" Grid.Column="0" Grid.Row="0"/>
<TextBox Text="{Binding DeliveryDate}" Grid.Column="1" Grid.Row="0"/>
<TextBlock Text="Delivery Time:" Grid.Column="0" Grid.Row="1"/>
<TextBox Text="{Binding DeliveryTime}" Grid.Column="1" Grid.Row="1"/>
...
</Grid>
</DataTemplate>
</Window.Resources>
...
<Button Content="AddChild" Click="AddChildClick"/>
...
<ScrollViewer>
<ItemsControl ItemsSource="{Binding AllChildren}" ItemsTemplate="{StaticResource ChildTemplate}">
<ItemsControl.PanelTemplate>
<ItemsPanelTemplate><StackPanel Orientation="Horizontal"/></ItemPanelTemplate>
<ItemsControl.PanelTemplate>
</ScrollViewer>
...
</Window>
And in cs:
Set an object with all the form data as the Window's DataContext. I'll call this class PostDelveryData.
Create another class with the repeating data. I'll call it ChildDeliveryData.
Add a property of type ObservableCollection<ChildDeliveryData> called AllChildren to PostDeliveryData; it's important it'll be ObservableCollection and not any other type of collection.
Now, for the magic:
private void AddChildClick(object sender, RoutedEvetnArgs e)
{
((PostDeliveryData)DataContext).AllChildren.Add(new ChildDeliveryData());
}
And when you add the new item to the list another copy of the entire data template will be added.
I'm not sure that you're using the correct approach here. I would approach the problem by creating a "ChildGridControl" with a Child property, and let the Child property handle the databinding. Adding a new child to the GUI would involve creating a new instance of the ChildGridControl.
If I am understanding correctly, you should create a UserControl, which wraps your Grid and subsequent controls inside. And use this User control anywhere you wanted to replicate that UI.