Combobox WPF list

Question

I'm doing this little program just to learn how to bind some data from a list of objects to a combobox. What I want to do is to show in a textblock the translation of some words that are in the combobox. In the combobox I want the english word, and in the textblock spanish for example.

For that I created a combobox in xaml called cmbBox1 and a textblock called tb1.

Then I created the class "word":

public class word { public string english { get; set; } public string spanish { get; set; } }

And the lists with three words:

 private void Window_Loaded_1(object sender, RoutedEventArgs e) { // Creation of a list of objects of class "word" List<word> mydictionary = new List<word>(); word word1 = new word(); word1.english = "Hello"; word1.spanish = "Hola"; word word2 = new word(); word2.english = "Goodbye"; word2.spanish = "Adios"; word word3 = new word(); word3.english = "How are you?"; word3.spanish = "¿Qué tal?"; mydictionary.Add(word1); mydictionary.Add(word2); mydictionary.Add(word3); //Adding the objects of the list mydictionary to combobox <--- foreach (word myword in mydictionary) { cmbBox1.Items.Add(myword); } }

And int XAML i have this for my combobox:

 <ComboBox x:Name="cmbBox1" HorizontalAlignment="Left" Margin="133,122,0,0" VerticalAlignment="Top" Width="120" ItemsSource="{Binding Path=word}" DisplayMemberPath="english" SelectedValuePath="english" SelectedValue="{Binding Path=word}" />

I would like to have the property "english" displayed in the combobox and the property "spanish" in the textblock. It would be nice too if when the user click on a word in the combobox a different method is executed, for example MessageBox.Show("You selected the word" + word1.english).

The purpose of all this is to learn how to do something more complex: I will be loading a text files with some channels of data, each channel will have a bunch of propreties and I want to be able to select the channel for then plotting it. Thank you very much.

Cellcon · Accepted Answer · 2013-05-11 11:39:00Z

I think you should start learning C# and WPF step by step. Trying to bind to a class instead of binding to an instance or collection is not a Problem of understanding WPF.

But I know there are several people having big Problems understanding databinding in WPF, so I will pick up your post to describe this simple example.

1) Do not add the items manually (cmbBox1.Items.Add(myword);) - that's what databinding is for.

2) You cannot bind to a type (like Binding Path=word). You have to bind to an objet/collection. The object/collection has to be a property, not a local collection like your implementation of mydictionary.

public List<Word> MyDictionary {get; set;} public Word SelectedWord {get; set;} ItemsSource="{Binding Path=MyDictionary}" SelectedItem="{Binding SelectedWord}"

3) You have to set the object containing the data collections as DataContext, in your case:

DataContext = this;

4) To react to a selection change, handle the SelectionChanged Event:

 <ComboBox [...] SelectionChanged="cmbBox1_SelectionChanged" />

Full WPF:

<Window x:Class="WpfApplication1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded"> <Grid> <ComboBox x:Name="cmbBox1" HorizontalAlignment="Left" Margin="133,122,0,0" VerticalAlignment="Top" Width="120" ItemsSource="{Binding MyDictionary}" DisplayMemberPath="english" SelectedValuePath="english" SelectedItem="{Binding SelectedWord}" SelectionChanged="cmbBox1_SelectionChanged" /> </Grid> </Window>

Full C#:

public class Word { public string english { get; set; } public string spanish { get; set; } } public partial class MainWindow : Window { public List<Word> MyDictionary {get; set;} public Word SelectedWord {get; set;} public MainWindow() { InitializeComponent(); } private void Window_Loaded(object sender, RoutedEventArgs e) { MyDictionary = new List<Word>(); Word word1 = new Word(); word1.english = "Hello"; word1.spanish = "Hola"; Word word2 = new Word(); word2.english = "Goodbye"; word2.spanish = "Adios"; Word word3 = new Word(); word3.english = "How are you?"; word3.spanish = "¿Qué tal?"; MyDictionary.Add(word1); MyDictionary.Add(word2); MyDictionary.Add(word3); DataContext = this; } private void cmbBox1_SelectionChanged(object sender, SelectionChangedEventArgs e) { MessageBox.Show("You have selected the word \"" + SelectedWord.spanish + "\""); } }

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