I have ItemsControl that is bound to collection of type Student.
Inside the ItemTemplate I have a TextBox that uses IValueConverter to do some custom calculations and logic. I want to pass the actual Student object to the value converter, instead a property of it. How can I do that? Here's a sample of my code.
<ItemsControl ItemsSource="{Binding StudentList}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}" />
<TextBlock Text="{Binding ????, Converter={StaticResource MyConverter}}" />
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
In the code I have this
public class MyValueConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
// I want 'value' to be of type Student.
return null;
}
}
You can just leave out the path. That way you get at the actual object bound to.
<TextBlock Text="{Binding Converter={StaticResource MyConverter}}"/>
or if you want to be explicit about it:
<TextBlock Text="{Binding Path=., Converter={StaticResource MyConverter}}"/>
Related
I'm using WPFLocalizationExtension for my WPF app.
I have one ComboBox for languages selection. Item source is an ObservableCollection<KeyValuePair<string, string>> as below:
TITLE_LANGUAGE_ENGLISH : en
TITLE_LANGUAGE_VIETNAMESE: vi-VN
This is my xaml code:
<TextBlock Text="{lex:Loc TITLE_LANGUAGE}"></TextBlock>
<ComboBox Grid.Column="1"
ItemsSource="{Binding AvailableLanguages}">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{lex:Loc Key={Binding Key}}"></TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
When I run the application, it throws me an exeption as below:
A 'Binding' cannot be set on the 'Key' property of type 'LocExtension'. A 'Binding' can only be set on a DependencyProperty of a DependencyObject
How can I translate the ItemTemplate ?
Thank you,
You could use an IMultiValueConverter together with a MultiBinding, so that you don't loose the ability to update the localization on-the-fly.
<ComboBox ItemsSource="{Binding AvailableLanguages}">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock>
<TextBlock.Text>
<MultiBinding>
<MultiBinding.Bindings>
<Binding Path="Key" Mode="OneTime"/>
<Binding Path="Culture" Source="{x:Static lex:LocalizeDictionary.Instance}"/>
</MultiBinding.Bindings>
<MultiBinding.Converter>
<l:TranslateMultiConverter/>
</MultiBinding.Converter>
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
And here is the converter:
class TranslateMultiConverter : DependencyObject, IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
if (values.Length == 2)
{
var key = values[0] as string;
if (key == null)
{
return DependencyProperty.UnsetValue;
}
var cultureInfo = (values[1] as CultureInfo) ?? culture;
return LocalizeDictionary.Instance.GetLocalizedObject(key, this, cultureInfo);
}
return values.FirstOrDefault();
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
The LocalizeDictionary will raise a PropertyChanged event when the app's language will change causing the MultiBinding to refresh the values.
Note that the converter is a DependencyObject too. This is to provide the context to the LocalizeDictionary when calling the GetLocalizedObject method.
you have to bind to the Path Key directly. The TextBlock at DataTemplate points directly to a single KeyValuePair object, that you can access the property Key directly.
<TextBlock Text="{lex:Loc TITLE_LANGUAGE}"></TextBlock>
<ComboBox Grid.Column="1"
ItemsSource="{Binding AvailableLanguages}">
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=Key}" />
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
Update:
Maybe you have to add a Converter. Try WPFLocalizeExtension.TypeConverters.DefaultConverter or implement a class deriving from IValueConverter by yourself.
<ComboBox.Resources>
<cv:DefaultConverter x:Key="DConv" />
</ComboBox.Resources>
<ComboBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=Key, Converter={StaticResource DConv}}" />
</DataTemplate>
</ComboBox.ItemTemplate>
Each item of my Employee's list has Post property. This property is Int64 type. Also, I have some ObservableDictionary<Int64,String> as static property. Each Employe must display the String value by its key.
DataTemplate for Employe item (I deleted the superfluous):
<DataTemplate x:Key="tmpEmploye">
<Border BorderThickness="3" BorderBrush="Gray" CornerRadius="5">
<StackPanel Orientation="Vertical">
<TextBlock Text="{Binding Path=Post}"/>
</StackPanel>
</Border>
</DataTemplate>
But this code displayed the Int64 value, not the String. String for getting static dictionary:
"{Binding Source={x:Static app:Program.Data}, Path=Posts}"
I know how solve it problem for ComboBox, but I don't know for TextBlock. For ComboBox I wrote it (it is works fine):
<ComboBox x:Name="cboPost" x:FieldModifier="public" Grid.Row="4" Grid.Column="1" HorizontalAlignment="Stretch"
VerticalAlignment="Stretch" Margin="2" Grid.ColumnSpan="2"
ItemsSource="{Binding Source={x:Static app:Program.Data}, Path=Posts}" DisplayMemberPath="Value"
SelectedValuePath="Key"
SelectedValue="{Binding Path=Post, Mode=TwoWay}">
</ComboBox>
But how can I solve it for TextBlock?
mmmmm, I'm sure I have developed something for this scenario before but I can't remember or find anything related!
IMO you can use a converter, so you pass your Post (Int64) to the converter and it returns the string value from the dictionary, although it must be a better solution.
[ValueConversion(typeof(Int64), typeof(string))]
public class PostToStringConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
// validation code, etc
return (from p in YourStaticDictionary where p.Key == Convert.ToInt64(value) select p.Value).FirstOrDefault();
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
}
}
XAML:
<Window ...
xmlns:l="clr-namespace:YourConverterNamespace"
...>
<Window.Resources>
<l:PostToStringConverter x:Key="converter" />
</Window.Resources>
<Grid>
<TextBlock Text="{Binding Post, Converter={StaticResource converter}}" />
</Grid>
</Window>
I have 3 user controls
Control 1
Control 2
Control 3
I have a stack panel that contains an ItemsControl
<UserControl.Resources>
<DataTemplate x:Key="Template1">
<my:UserControl1 Height="117"/>
</DataTemplate>
<DataTemplate x:Key="Template2">
<my:UserControl3 Height="117"/>
</DataTemplate>
<DataTemplate x:Key="Template3">
<my:UserControl3 Height="117"/>
</DataTemplate>
</UserControl.Resources>
<StackPanel Name="stackPanel3" Orientation="Vertical" VerticalAlignment="Bottom" Width="Auto">
<ItemsControl ItemsSource="{Binding BlocksForMonth.Blocks}" ItemTemplate="{StaticResource Template1}">
</ItemsControl>
</StackPanel>
BlocksForMonths.Blocks is a list of view models. The Blocks class has a property called ClipType. If the clipType is 1, I want to use Template1. If its 2 I want to use Template 2. If its 3 I want to use Template 3
These templates contain different user controls
How can I do this through binding?
I have considered 1 template with the 3 controls, but I dont know how to bind the visibility?
In this XAML I am binding to a list not a single item
Paul
I would put the 3 controls in the same template and use Visibility to display the correct one. What I would do is build an IValueConverter to convert the deciding value (your case it's ClipType) and compare that to the ConverterParameter. If they are equal, return Visibility.Visible, otherwise return Visibility.Collapsed.
<UserControl.Resources>
<my:ClipTypeToVisibilityConverter x:Key="converter"/>
<DataTemplate x:Key="Template">
<StackPanel>
<my:UserControl1 Height="117" Visibility={Binding ClipType, Converter={StaticResource converter}, ConverterParameter=1} />
<my:UserControl2 Height="117" Visibility={Binding ClipType, Converter={StaticResource converter}, ConverterParameter=2} />
<my:UserControl3 Height="117" Visibility={Binding ClipType, Converter={StaticResource converter}, ConverterParameter=3} />
</StackPanel>
</DataTemplate>
</UserControl.Resources>
<StackPanel Name="stackPanel3" Orientation="Vertical" VerticalAlignment="Bottom" Width="Auto">
<ItemsControl ItemsSource="{Binding BlocksForMonth.Blocks}" ItemTemplate="{StaticResource Template}">
</ItemsControl>
</StackPanel>
This example assumes the ClipType property is on each item view model in the list being displayed.
Here is a C# example converter.
public class ClipTypeToVisibilityConverter: IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
var clipType = value.ToString();
if (clipType == (string)parameter))
return Visibility.Visible;
return Visibility.Collapsed;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
Sorry, everything was air-code. But I think you get the idea.
In a DataGridTemplateColumn DataTemplate,
I want to bind 2 controls to a string field of format "[name]:[value]" i.e. the string is delimited by colon ":". I need to bind control a) to the [name] part and control b) the value part.
I have been able to successfully use an IValueConverter to split the string for display:
public class NameAndValueConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
string rtn = "";
string[] split = value.ToString().Split(':');
if (split.Count() == 2)
{
if(parameter.ToString() == "Name")
rtn = split[0];
if(parameter.ToString() == "Value")
rtn = split[1];
}
return rtn;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new InvalidOperationException("NameAndValueConverter can only be used OneWay.");
}
}
And the XAML:
<DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<StackPanel.Resources>
<local:NameAndValueConverter x:Key="NameAndValueConverter" />
</StackPanel.Resources>
<TextBox x:Name="namePart" Text="{Binding Path=FieldType, Converter={StaticResource NameAndValueConverter}, ConverterParameter='Name'}" />
<TextBox x:Name="valuePart" Text="{Binding Path=FieldType, Converter={StaticResource NameAndValueConverter}, ConverterParameter='Value'}" />
</StackPanel>
</DataTemplate>
</DataGridTemplateColumn.CellEditingTemplate>
But the data may be edited in the Textboxes so how can I access the 2 TextBox values in ConvertBack so that they can be joined again?
Doing this in the XAML:
<DataGridTemplateColumn.CellEditingTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<StackPanel.Resources>
<local:NameAndValueConverter x:Key="NameAndValueConverter" />
</StackPanel.Resources>
<TextBox x:Name="namePart" Text="{Binding Path=FieldType, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource NameAndValueConverter}, ConverterParameter='Name'}" />
<TextBox x:Name="valuePart" Text="{Binding Path=FieldType, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource NameAndValueConverter}, ConverterParameter='Value'}" />
</StackPanel>
</DataTemplate>
</DataGridTemplateColumn.CellEditingTemplate>
should be enough. You need a TwoWay binding to edit from UI, and when you set UpdateSourceTrigger to PropertyChanged the TextBox will update itself automatically when the property will be modified in the ViewModel (you'd obviously need to implement INotifyPropertyChanged )
The content of my DataGrid (Product and Price, for example) is loaded from an XML file and every thing is treated as text when sorted by the DataGrid.
How to tell the DataGrid to treat Price as number when sorting? Thanks.
Here's the relevant XAML (there's NO code behind). I want to sort Length as number:
<DataGridTemplateColumn Header="Length" SortMemberPath="Length" Width="100">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock TextAlignment="Right" VerticalAlignment="Center" Text="{Binding XPath=Length}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
You could add a Converter to your Binding.
Step 1 : Create the converter class.
[ValueConversion(typeof(string), typeof(int))]
public class StringToIntConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return Int32.Parse(value.ToString());
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return value.ToString();
}
}
A little validation might be advisable, but this is only a rudimentary example.
Step 2: instantiate the converter. Make sure you add the Namespace declaration to your Xaml.
<Window.Resources>
<StringToIntConverter x:Name="stringToInt"/>
</Window.Resources>
Step3 : use it
<DataGridTemplateColumn Header="Length" SortMemberPath="Length" Width="100">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<TextBlock TextAlignment="Right" VerticalAlignment="Center" Text="{Binding XPath=Length, Converter={StaticResource stringToInt}}"/>
</DataTemplate>
</DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>
Without code, this is just a guess, but I'm assuming you are doing a xml deserialization into an object, that is put in a list and then your datagrid is bound to the list. If you make the price data field in the list class an int, then datagrid will treat it as a number.