I have Languages enum. And My Model.Translations is representing different languages translations:
public ObservableCollection<LanguageValue> Translations { get; set; }
public class LanguageValue
{
public Language Key { get; set; }
public string Value { get; set; }
}
I want my view to have label - textbox list for each item in Translations.
But in Label I want to have something like "Caption ({0})", where parameter is Language name (enum to string representation). This text itself is coming from Resources.
Something like:
<ItemsControl ItemsSource="{Binding Path=Translations}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid Margin="5,2,5,2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="30*"/>
<ColumnDefinition Width="70*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" x:Name="ItemLabel" VerticalAlignment="Center"
Text="{Binding Path=Key, Converter=languageConverter, ConverterParameter={x:Static res:Resources.lblCaption}}" />
<TextBox Grid.Column="1" x:Name="ItemText" VerticalAlignment="Center"
Text="{Binding Path=Value, Mode=TwoWay}" />
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
My LanguageConverter:
[ValueConversion(typeof(Language), typeof(string))]
public class LanguageToDisplayConverter : IValueConverter
{
public object Convert(object value, Type t, object parameter, CultureInfo culture)
{
return string.Format(parameter.ToString(), ((Language)value).ToString());
}
public object ConvertBack(object value, Type t, object parameter, CultureInfo culture)
{
//I guess I don't need this anyway?
return null;
}
}
But I've got error:
The TypeConverter for "IValueConverter" does not support converting from a string.
What is wrong?
you should declare your converter as a resource (in a Window, or app-wide in App.xaml):
<Window.Resources>
<views:LanguageToDisplayConverter x:Key="languageConverter"/>
</Window.Resources>
and use accordingly:
Text="{Binding Path=Key, Converter={StaticResource languageConverter}, ...
the error "The TypeConverter for "IValueConverter" does not support converting from a string" indicates that wpf didn't recognize string "languageConverter" as a converter
the same effect can be also achieved by using StringFormat property of Binding, without converter:
Text="{Binding Path=Key, StringFormat={x:Static res:Resources.lblCaption}}"
Related
I am trying to bind a ComboBox ItemsSource to the TextWrapping enum within the System.Windows namespace. The end result would be a drop down where the user can select which type of text wrapping to apply for a given object within my application. Everything works fine when I bind to a custom enum, but I can't figure out what path/source I need to use to bind to an enum within the System.Windows namespace. How can I access this namespace through data binding?
<DataTemplate
DataType="{x:Type MyObjectWrapper}"
>
<StackPanel Orientation="Horizontal">
<TextBlock Text="Text Wrapping" VerticalAlignment="Center" Margin="5,5,0,5"/>
<ComboBox
ItemsSource="{Binding Source={???}, Converter={local:MyEnumConverter}}"
SelectedValuePath="Value"
DisplayMemberPath="Description"
SelectedValue="{Binding Path = TextWrapping}"
VerticalAlignment="Center"
Margin="5"
/>
</StackPanel>
</DataTemplate>
Update: My enum converter just needs the enum class passed in the xaml, which looks like this for custom enums:
<ComboBox
ItemsSource="{Binding Path=MyCreatedEnum, Converter={local:MyEnumConverter}}"
SelectedValuePath="Value"
DisplayMemberPath="Description"
SelectedValue="{Binding Path = TextWrapping}"
VerticalAlignment="Center"
Margin="5"
/>
Found this over the web under this link.
http://brianlagunas.com/a-better-way-to-data-bind-enums-in-wpf/
Here is the modified code to suite your requirement.
<Grid x:Name="LayoutRoot">
<Grid.Resources>
<local:EnumToListConverter x:Key="enumToListConv" />
</Grid.Resources>
<ComboBox
Margin="5"
VerticalAlignment="Center"
ItemsSource="{Binding Source={local:EnumBindingSource {x:Type sysWin1:TextWrapping}}, Converter={StaticResource enumToListConv}}"
SelectedValuePath="Value" />
</Grid>
public class EnumBindingSourceExtension : MarkupExtension
{
private Type _enumType;
public Type EnumType
{
get { return this._enumType; }
set
{
if (value != this._enumType)
{
if (null != value)
{
Type enumType = Nullable.GetUnderlyingType(value) ?? value;
if (!enumType.IsEnum)
throw new ArgumentException("Type must be for an Enum.");
}
this._enumType = value;
}
}
}
public EnumBindingSourceExtension() { }
public EnumBindingSourceExtension(Type enumType)
{
this.EnumType = enumType;
}
public override object ProvideValue(IServiceProvider serviceProvider)
{
if (null == this._enumType)
throw new InvalidOperationException("The EnumType must be specified.");
Type actualEnumType = Nullable.GetUnderlyingType(this._enumType) ?? this._enumType;
return actualEnumType;
}
}
public class EnumToListConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
var items = Enum.GetValues((Type)value);
return items;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
refers to implementing a multilanguage interface now I have a problem. I have a grid where its ItemSource it's a Dictionary<string, string>: I can't give the key value as parameter of the markup extension because I have the following exception
A 'Binding' cannot be set on the 'Value1' property of type 'TranslateMarkupExtension'.
A 'Binding' can only be set on a DependencyProperty of a DependencyObject.
This is the xaml where I use the markup extension:
<ItemsControl ItemsSource="{Binding MyDictionary}" Grid.Row="0">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid Margin="10">
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<Label Content="{TranslateMarkup Value1 = {Binding Path = Key}}" Grid.Column="0" />
<TextBox Tag="{Binding Key, Mode=OneWay}" Text="{Binding Value, Mode=OneWay}" Width="200" Height="46" VerticalContentAlignment="Center" Grid.Column="1" LostFocus="TextBox_OnLostFocus" />
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
I can't find any workaround..I need the dictionary as item source because the label will show the key and the textbox the corresponding value..I tried also replacing the dictionary with a list of object but the problem still remains.
Does anyone have a good hint? Thanks in advance.
As suggested by Ed Plunkett, the solution is the ValueConverter.
So the label is know this:
<Label Content="{Binding Key, Converter={StaticResource MultiLangConverter}}" Grid.Column="0" />
where my ValueConverter is the following:
public class StringToMultiLangConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
var stringValue = (string) value;
if (string.IsNullOrEmpty(stringValue))
return string.Empty;
string multiLang = LangTranslator.GetString(stringValue);
return multiLang ?? value;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
return DependencyProperty.UnsetValue;
}
}
Thanks for the help!
I have two models in my application:
class Line
{
string line_id { get; set; }
string color { get; set; }
}
class Point
{
string point_id { get; set; }
string line_id { get; set; }
int weight { get; set; }
}
And I have two ObservableCollection:
lines - ObservableCollection<Line>
points - ObservableCollection<Point>
I want to display two ListBox'es : first (outer) to display lines, and second (inner) to display the points which belongs to this line.
<ListView x:Name="lvPoint" ItemsSource="{Binding}">
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding color, Mode=TwoWay}" />
<ListBox ItemsSource="{Binding SOMETHING, Mode=TwoWay}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding weight, Mode=OneWay}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
I set DataContext for outer ListBox in the code:
lvPoint.DataContext = lines;
How can I set DataContext for inner ListBox to display Points for each Line ?
Your Line model is not good for this scenario. It should have a property such as called Points which contains the interested points belonging to the Line. Then the Binding is just simple:
class Line {
public string line_id { get; set; }
public string color { get; set; }
ObservableCollection<Point> _points;
public ObservableCollection<Point> Points {
get {
if (_points == null) _points = new ObservableCollection<Point>();
return _points;
}
}
}
Then in XAML code you can just set the Path to Points like this:
<ListBox ItemsSource="{Binding Points, Mode=TwoWay}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding weight, Mode=OneWay}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
The model above is just an example showing the main idea. The full implementation should of course be different and more advanced depending on the current project.
Update: Without using the model above, you can try using Converter for the Binding. The Binding is set directly to the current item (Line). The Converter will convert Line to points (maybe based on line_id and your query method):
public class LineToPointsConverter : IValueConverter {
public object Convert(object value, Type targetType, object parameter,
System.Globalization.CultureInfo culture){
var line = value as Line;
//convert to points by querying the points based on line.line_id here
return ...
}
public object ConvertBack(object value, Type targetType,
object parameter,
System.Globalization.CultureInfo culture){
return Binding.DoNothing;
}
}
Define a static property of LineToPointsConverter or create an instance of that converter in Resources:
<Window.Resources>
<local:LineToPointsConverter x:Key="lineToPointsConverter"/>
</Window.Resources>
Then in XAML code set that converter:
<ListBox ItemsSource="{Binding Mode=TwoWay, Path=.,
Converter={StaticResource lineToPointsConverter}}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding weight, Mode=OneWay}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
I'm very new to WPF so sorry if this is obvious but I can't seem to find any decent examples on the internet showing how it's done.
I have a DataGrid which is bound to a collection of DataItem called MyCollection. I want to create a generic DataTemplate that I can use for multiple columns in the grid (and elsewhere in the application should I need it).
E.g.
<DataGrid ItemsSource="{Binding MyCollection}" AutoGenerateColumns="False" SelectionUnit="Cell" EnableColumnVirtualization="True">
<DataGrid.Columns>
<DataGridTemplateColumn Header="File path" CellTemplate="{StaticResource FileSelectorEditorTemplate}" CellEditingTemplate="{StaticResource FileSelectorEditorTemplate}" />
<DataGridTemplateColumn Header="File path2" CellTemplate="{StaticResource FileSelectorEditorTemplate}" CellEditingTemplate="{StaticResource FileSelectorEditorTemplate}" />
<DataGridTemplateColumn Header="File path3" CellTemplate="{StaticResource FileSelectorEditorTemplate}" CellEditingTemplate="{StaticResource FileSelectorEditorTemplate}" />
...
My DataTemplate is defined at the moment in my Application resources as
<DataTemplate x:Key="FileSelectorEditorTemplate">
<Grid>
<TextBox Text="{Binding FilePath.PhysicalPath}" HorizontalAlignment="Stretch" Margin="0,0,35,0" />
<Button Content="..." Height="25" Width="25" Margin="0,0,5,0" HorizontalAlignment="Right" Click="FileOpen_Click" />
</Grid>
</DataTemplate>
Now the problem is that the binding is specified in the DataTemplate, whereas I need to apply a different binding for each of the properties FilePath, FilePath2, FilePath3 on the view model. I don't seem to be able to specify the Binding on the DataGridTemplateColumn though?
I'd appreciate any pointers in the right direction,
Thanks!
The binding on the DataGridTemplateColumn is specified in its CellTemplate.
If you want different bindings for the three columns, I'd say you would have to make a different DataTemplate for each of the columns. There might be some workaround, but I doubt it would be pretty.
Edit:
Having different templates you can use a DataTemplateSelector to select the right template for the current object.
Using IValueConverter (Just a quick sketch, but should work):
<DataTemplate x:Key="GenericTemplate" >
<TextBlock FontSize="14" >
<TextBlock.Text>
<Binding Converter="{StaticResource NewValue}" Path="Me" />
</TextBlock.Text>
</TextBlock>
</DataTemplate>
public class NewValueConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
someContainer obj = value as someContainer;
if (obj.type == MyType.First)
return (string)(obj.val1);
else
return (string)(obj.val2);
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
public enum MyType
{
First,
Second
}
public class someContainer
{
public someContainer Me { get; set; }
public string val1 { get; set; }
public string val2 { get; set; }
public MyType type;
public someContainer()
{
Me = this;
val1 = "string1";
val2 = "string2";
}
}
...
public ObservableCollection<someContainer> myList {get; set;}
...
<StackPanel Margin="0,10,0,0" Orientation="Vertical" Grid.Column="2">
<ItemsControl ItemsSource="{Binding MyList}" ItemTemplate="{StaticResource GenericTemplate}" />
</StackPanel>
If you can't use the option of Jesper Gaarsdal you might also be able to use a CellStyle and define the binding in the column-declaration.
see this SO for example: How to reuse WPF DataGridTemplateColumn (including binding)
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>