WPF:
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication1"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<local:BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"
True="Visible"
False="Collapsed" />
</Window.Resources>
<Canvas>
<StackPanel Canvas.Left="100" Canvas.Top="100" Width="200" Height="100">
<ListBox>
<ListBoxItem>one</ListBoxItem>
<ListBoxItem>two</ListBoxItem>
<ListBoxItem>three</ListBoxItem>
</ListBox>
<StackPanel Orientation="Horizontal"
Visibility="{Binding
RelativeSource={RelativeSource AncestorType={x:Type StackPanel}},
Path=IsMouseOver,
Converter={StaticResource BooleanToVisibilityConverter}}">
<Button>one</Button>
<Button>two</Button>
<Button>three</Button>
</StackPanel>
</StackPanel>
</Canvas>
</Window>
Code:
public abstract class BooleanConverter<T> : IValueConverter
{
public BooleanConverter(T trueValue, T falseValue)
{
True = trueValue;
False = falseValue;
}
public T True { get; set; }
public T False { get; set; }
public virtual object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
return value is bool && ((bool)value) ? True : False;
}
public virtual object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
return value is T && EqualityComparer<T>.Default.Equals((T)value, True);
}
}
public class BooleanToVisibilityConverter : BooleanConverter<Visibility>
{
public BooleanToVisibilityConverter()
: base(Visibility.Visible, Visibility.Collapsed)
{ }
}
My the mouse hovers over the ListBox, the buttons are displayed as expected. If the mouse moves below the ListBox on the right side, the buttons vanish. Why is IsMouseOver false over there? Shouldn't the height of the outer StackPanel increase when the inner StackPanel's Visibility property changes from Collapsed to Visible?
Here's the project if you want to play with it: http://dl.dropbox.com/u/4220513/WpfApplication1.zip
You need to set the background of the StackPanel (the outer one) to Transparent to detect mouse over. If background is null as in your sample, hit testing will fail.
Use a background for your StackPanel like <StackPanel Background="Transparent">...
Related
I have am attempting to build a tree view where:
1. The TreeViewItems are generated by a list in my model.
2. Each TreeViewItem contains a ComboBox, and a dynamic element whose template I want to change based on the value selected in the ComboBox.
Here is my current xaml code.
<Window x:Class="MyTestWPF.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:MyTestWPF"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Window.Resources>
<local:NodeTypeToTemplateConverter x:Key="NodeTypeToTemplateConverter"/>
<DataTemplate x:Key="Template1">
<TextBlock Text="Template 1" />
</DataTemplate>
<DataTemplate x:Key="Template2">
<TextBlock Text="Template 2" />
</DataTemplate>
<Style x:Key="MyNodeTemplate" TargetType="ContentPresenter">
<Setter Property="ContentTemplate" Value="{StaticResource Template1}"/>
<Style.Triggers>
<DataTrigger Binding="{Binding Path=NodeType}">
<DataTrigger.Value>
<local:NodeTypesEnum>Type1</local:NodeTypesEnum>
</DataTrigger.Value>
<Setter Property="ContentTemplate" Value="{Binding Converter={StaticResource NodeTypeToTemplateConverter}}"/>
</DataTrigger>
</Style.Triggers>
</Style>
<HierarchicalDataTemplate DataType="{x:Type local:MyTreeNode}"
ItemsSource="{Binding Nodes}">
<StackPanel Orientation="Horizontal">
<ComboBox ItemsSource="{Binding Path=GetAvailableNodeType}"
SelectedItem="{Binding Path=NodeType}" />
<ContentPresenter Style="{StaticResource MyNodeTemplate}" Content="{Binding}" />
</StackPanel>
</HierarchicalDataTemplate>
</Window.Resources>
<TreeView x:Name="MyTree" ItemsSource="{Binding MyTreeModel}" />
</Window>
And its code-behind:
using System.Windows;
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
this.DataContext = new
{
MyTreeModel = new MyTreeNode[] {
new MyTreeNode() { Name = "1", Nodes = new MyTreeNode[] { new MyTreeNode() { Name= "2" } } }
}
};
}
}
The tree node type:
namespace MyTestWPF
{
public class MyTreeNode
{
public string Name { get; set; }
public NodeTypesEnum NodeType { get; set; }
public MyTreeNode[] Nodes { get; set; }
public NodeTypesEnum[] GetAvailableNodeType()
{
return new NodeTypesEnum[] { NodeTypesEnum.Type1, NodeTypesEnum.Type2 };
}
}
public enum NodeTypesEnum
{
Type1 = 0,
Type2 = 1
}
}
The Converter (NodeTypeToTemplateConverter) receives the whole ViewModel, and returns the name of the relevant template based on values in the model.
using System;
using System.Globalization;
using System.Windows.Data;
namespace MyTestWPF
{
public class NodeTypeToTemplateConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if((value as MyTreeNode).NodeType == NodeTypesEnum.Type1)
{
return "Template1";
} else
{
return "Template2";
}
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
}
The problem is that the above code causes a stack overflow exception. The first item in the TreeView endlessly calls NodeTypeToTemplateConverter's Convert method.
I figured it had to do with the DataTrigger.Value. Setting that to a value different from the default NodeType allows the page to load without overflow, but the moment any ComboBox is set to NodeType1, stack overflow.
I attempted to simply remove the DataTrigger.Value element, but that causes the Converter to never be called at all...
How can I dynamically build the template name based on the value selected by its neighboring ComboBox?
You probably want to use a DataTemplateSelector rather than a converter.
public class ComboBoxItemTemplateSelector : DataTemplateSelector
{
public DataTemplate Template1 { get; set; }
public DataTemplate Template2 { get; set; }
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
//Logic to select template based on 'item' value.
if (item == <template1Value>) return Template1; //TODO: replace <template1Value>
else if (item == <template2Value>) return Template2; //TODO: replace <template2Value>
else return new DataTemplate();
}
}
<local:ComboBoxItemTemplateSelector x:Key="ComboBoxItemTemplateSelector">
<local:ComboBoxItemTemplateSelector.Template1>
<DataTemplate>
<TextBlock Text="" />
</DataTemplate>
</local:ComboBoxItemTemplateSelector.Template1>
<local:ComboBoxItemTemplateSelector.Template2>
<DataTemplate>
<TextBlock Text="" />
</DataTemplate>
</local:ComboBoxItemTemplateSelector.Template2>
</local:ComboBoxItemTemplateSelector>
<ContentPresenter Content="{Binding NodeType}" ContentTemplateSelector="{StaticResource ComboBoxItemTemplateSelector}"/>
I have not fully tested this code, so let me know if you have any issues.
EDIT:
The template selector is only executed when the content changes so this won't work if you use {Binding}. A workaround for this would be to have the DataTemplate content bind to the parent's DataContext.
<DataTemplate>
<TextBlock Text="" DataContext="{Binding DataContext, RelativeSource={RelativeSource AncestorType=ContentPresenter}}"/>
</DataTemplate>
If this workaround is not acceptable, there are other ways to do this as well.
I am using "BooleanToVisibilityConverter" to show one image when radio button is checked. Is their any way I can use same sort of style show another image when this radio button is unchecked?
<BooleanToVisibilityConverter x:Key="VisibilityConverter" />
<RadioButton Name="rbttest" IsChecked="True" GroupName="rbtMenuGroup"
Style="{StaticResource RadioButtonMenuStyle}" >
<WrapPanel>
<Image Source="/wpf1;component/Images/test1.png"
Visibility="{Binding IsChecked=false ???}" Style="{StaticResource MenuIconStyle}" />
<Image Source="/wpf;component/Images/test2.png"
Visibility="{Binding IsChecked, Converter={StaticResource
VisibilityConverter},ElementName = rbttest}"
Style="{StaticResource MenuIconStyle}" ></Image>
<TextBlock Text="This is testing" />
</WrapPanel>
</RadioButton>
I found a solution for the time being before I study the MVVM, DataBinding, DependencyProperty, ControlTemplates.
I have added the BooleanToVisibilityConverter class which allows reverse, I mean hide/collapse control when true and visible when false !
using System;
using System.Windows.Data;
using System.Windows;
namespace TestBooleanToVisibilityConverter
{
class BoolToVisibleOrHidden : IValueConverter
{
#region Constructors
/// <summary>
/// The default constructor
/// </summary>
public BoolToVisibleOrHidden() { }
#endregion
#region Properties
public bool Collapse { get; set; }
public bool Reverse { get; set; }
#endregion
#region IValueConverter Members
public object Convert(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
bool bValue = (bool)value;
if (bValue != Reverse)
{
return Visibility.Visible;
}
else
{
if (Collapse)
return Visibility.Collapsed;
else
return Visibility.Hidden;
}
}
public object ConvertBack(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture)
{
Visibility visibility = (Visibility)value;
if (visibility == Visibility.Visible)
return !Reverse;
else
return Reverse;
}
#endregion
}
}
Now you can reverse this very easily in the XAML.
<local:BoolToVisibleOrHidden x:Key="BoolToVisConverter" Collapse="True" Reverse="True"
/>
<local:BoolToVisibleOrHidden x:Key="BoolToVisConverter2" Collapse="True"
Reverse="false" />
---------------------------------------------------------------------------------
<RadioButton Name="rbttest" IsChecked="True" GroupName="rbtMenuGroup"
Style="{StaticResource RadioButtonMenuStyle}" >
<WrapPanel>
<--Show the image when radio button unchecked-->
<Image Source="/wpf1;component/Images/test1.png"
Visibility="{Binding IsChecked, Converter={StaticResource
BoolToVisConverter},ElementName = rbttest}" Style="{StaticResource MenuIconStyle}"
/>
<--Show the image when radio button checked-->
<Image Source="/wpf1;component/Images/test2.png"
Visibility="{Binding IsChecked, Converter={StaticResource
BoolToVisConverter2},ElementName = rbttest}"
Style="{StaticResource MenuIconStyle}" ></Image>
<TextBlock Text="This is testing" />
</WrapPanel>
Reference : http://www.rhyous.com/2011/02/22/binding-visibility-to-a-bool-value-in-wpf/
I have a List< Versions> where Version, amongst others has the properties VersionUUID, Label, SKU and IsSelected. I would like to bind this to a Combobox and have the selected item just select the IsSelected flag (unselected any previous set flag).
Note:The combobox is in a template, used inside a datagrid cell, so I can not just bind a SelectedItem to the model!
What I have so far is working, the datagrid updates the DB as expected, however the initial value is not set onLoad. If one version already has a IsSelected=true, I would like to have that showing int the Combobox, but it is always empty unless i Select one from the list.
<DataTemplate x:Key="dtDatagridVersionSelector">
<ComboBox Margin="0" Width="90" Style="{StaticResource DatagridComboBox}"
ItemsSource="{Binding Path=Versions, Mode=OneTime}">
<ComboBox.ItemTemplate >
<DataTemplate >
<RadioButton Focusable="false" IsEnabled="true"
GroupName="{Binding VersionUUID}"
IsChecked="{Binding IsSelected, Mode=TwoWay}">
<StackPanel Orientation="Horizontal" >
<TextBlock Margin="3,0,0,0" Text="{Binding Label}"/>
<TextBlock Foreground="Red" Margin="3,0,0,0"
Text="{Binding SKU}"/>
</StackPanel>
</RadioButton>
</DataTemplate>
</ComboBox.ItemTemplate>
<ComboBox.ItemContainerStyle>
<Style TargetType="ComboBoxItem">
<Setter Property="IsSelected"
Value="{Binding IsSelected, Mode=OneWay}" />
</Style>
</ComboBox.ItemContainerStyle>
</ComboBox>
</DataTemplate>
Also, the use of the Radiobox is not written in stone, if there is a better solution to achieve this so only one item isSelected, I'm all open for it
Thanx for any pointers
Andreas
<Window x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication1"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<local:SelectedItemConverter x:Key="selectedItemConverter"/>
</Window.Resources>
<Grid>
<ComboBox ItemsSource="{Binding Students}" SelectedItem="{Binding Students, Converter={StaticResource selectedItemConverter}}" DisplayMemberPath="Name"/>
</Grid>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
Students = new ObservableCollection<Student>();
Students.Add(new Student() { Name = "HArish", RollNo = 1, IsSelected = false });
Students.Add(new Student() { Name = "Arev", RollNo = 2, IsSelected = false });
Students.Add(new Student() { Name = "Pankaj", RollNo = 3, IsSelected = true });
Students.Add(new Student() { Name = "Deepak", RollNo = 4, IsSelected = false });
DataContext = this;
}
public ObservableCollection<Student> Students { get; set; }
}
public class Student
{
public string Name { get; set; }
public int RollNo { get; set; }
public bool IsSelected { get; set; }
}
public class SelectedItemConverter : IValueConverter
{
#region IValueConverter Members
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (value != null && value is IEnumerable<Student>)
return ((IEnumerable<Student>)value).Where(s => s.IsSelected).FirstOrDefault();
return null;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
#endregion
}
I hope this will help.
I have problem with binding visibility in listbox-item template with property in parent object. Here is a little snippet from custom xaml style template:
<!-- DATA BINDING ITEM TEMPLATE -->
<StackPanel Orientation="Vertical">
<TextBlock Height="19"
....
Text="{Binding InfoTop}"/>
<Rectangle Height="1"
....
Visibility="{Binding _linesVisibility[0], RelativeSource={RelativeSource AncestorType=my:PatientsList}}"/>
<TextBlock Height="19"
....
Text="{Binding InfoMiddle}"
Visibility="{Binding _linesVisibility[0], ElementName=patientsControl}"/>
<Rectangle Height="1"
....
Visibility="{Binding _linesVisibility[1]}"/>
<TextBlock Height="19"
....
Text="{Binding InfoBottom}"
Visibility="{Binding _linesVisibility[1]}"/>
</StackPanel>
I managed to bind Text value by assigning ItemsSource in code file but i can't bind Visibility. As you can see i tried some different ideas but none of them work.
I have public variable public Visibility[] _linesVisibility = new Visibility[2]; in my custom control. This control contains listbox with custom style as above. How to bind properly my _linesVisibility to listbox-item style ?
You can't bind directly to an array:
Visibility="{Binding _linesVisibility[1]}"
This will not work.
You need to bind to a property and your class needs to implement INotifyPropertyChanged:
private Visibility backingVariable;
public Visbilility PublicProperty
{
get { return backingVariable; }
set
{
backingVariable = value;
if (this.PropertyChanged != null)
{
this.PropertyChanged(this, new PropertyChangedEventArgs("PublicVariable"));
}
}
}
It doesn't have to be a property of type Visibility. It can be any type as long as you bind through a converter that returns Visibility:
public class BoolToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
bool visibility = (bool)value;
return visibility ? Visibility.Visible : Visibility.Collapsed;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
Visibility visibility = (Visibility)value;
return (visibility == Visibility.Visible);
}
}
Usage:
Visibility="{Binding SomeBoolean, Converter={StaticResource boolToVisibilityConverter}}"
where the converter is declared in XAML like this:
<UserControl.Resources>
<globalConverters:BoolToVisibilityConverter x:Key="boolToVisibilityConverter" />
</UserControl.Resources>
I would like to use a WPF ToggleButton to expand and collapse some controls in my application. How can I use XAML to accomplish this?
I'm thinking that I could somehow bind the Visibility attribute of some controls to the ToggleButton's IsChecked state, but I do not know how to do this.
Maybe I need to give my ToggleButton a Name, then bind using ElementName? Then I would need a ValueConverter for converting between a boolean value and a Visibility, correct? How could I make a generic ValueConverter for this purpose?
You need to bind the Visibility through a converter:
<Window
x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Window.Resources>
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
</Window.Resources>
<StackPanel>
<ToggleButton x:Name="toggleButton" Content="Toggle"/>
<TextBlock
Text="Some text"
Visibility="{Binding IsChecked, ElementName=toggleButton, Converter={StaticResource BooleanToVisibilityConverter}}"/>
</StackPanel>
</Window>
In Silverlight there is no BooleanToVisibilityConverter but it is easy to write your own with some added features:
using System;
using System.Globalization;
using System.Windows;
using System.Windows.Data;
namespace WpfApplication1 {
public class BooleanToVisibilityConverter : IValueConverter {
public Object Convert(Object value, Type targetType, Object parameter, CultureInfo culture) {
if (targetType == typeof(Visibility)) {
var visible = System.Convert.ToBoolean(value, culture);
if (InvertVisibility)
visible = !visible;
return visible ? Visibility.Visible : Visibility.Collapsed;
}
throw new InvalidOperationException("Converter can only convert to value of type Visibility.");
}
public Object ConvertBack(Object value, Type targetType, Object parameter, CultureInfo culture) {
throw new InvalidOperationException("Converter cannot convert back.");
}
public Boolean InvertVisibility { get; set; }
}
}
Now you can specify a converter that maps true to Collapsed and false to Visible:
<BooleanToVisibilityConverter
x:Key="InverseBooleanToVisibilityConverter" InvertVisibility="True"/>
Use the BooleanToVisibilityConverter:
<BooleanToVisibilityConverter x:Key="bvc" />
<TextBlock Visibility="{Binding IsChecked, ElementName=toggle, Converter={StaticResource bvc}}" />
Is there a reason why you aren't just using the Expander? It's based on the ToggleButton anyway.