WPF Combobox binding with List

Question

I have two properties, one which is a list of string and the other just a string.

private List<String> _property;
public List<String> Property
get
{
return new List<string>(){"string1", "string2"};
}
set{_property = value
}

public String SimpleStringProperty{get;set;}

I also have a Combobox defined in XAML as such

<Combobox ItemsSource="{Binding Property , Mode="TwoWay"}" Text="Select Option" />

Now the combobox correctly displays two options :"string1" and "string2"

When the user selects one or the other, I want to set SimpleStringProperty with that value. However, the 'value' im getting back from the combobox through the two way binding is not the selectedItem, but the List<String>. How can I do this right? I'm fairly new to wpf, so please excuse the amateurism.

Chris · Accepted Answer · 2015-01-21T20:40:21.673

27

<Combobox ItemsSource="{Binding Property}" SelectedItem="{Binding SimpleStringProperty, Mode=TwoWay}" Text="Select Option" />

That's untested, but it should at least be pretty close to what you need.

edited Jan 21 '15 at 20:40

answered Feb 20 '14 at 04:27

Chris

971
7
15

score 3 · Answer 2 · answered Feb 20 '14 at 04:27

You need to bind to the String property using the SelectedItem property of the combobox.

<Combobox ItemsSource="{Binding Property}" 
          SelectedItem="{Binding SimpleStringProperty}" 
          IsSynchronizedWithCurrentItem="True" 
          Text="Select Option" />

score 2 · Answer 3 · edited Jul 15 '19 at 21:42

2

What helped me:

Using SelectedItem
Adding UpdateSourceTrigger=PropertyChanged
IsSynchronizedWithCurrentItem="True" to be sure Selected item always synchronized with actual value
Mode=TwoWay if you need to update as from source as from GUI

So at the end best way, if source is

List<string>

Example:

 <ComboBox 
    IsSynchronizedWithCurrentItem="True"
    ItemsSource="{Binding SomeBindingPropertyList}"
    SelectedItem="{Binding SomeBindingPropertySelectedCurrently, 
                    Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />

Additional Info

Difference between SelectedValue and SelectedItem:
1. https://stackoverflow.com/a/4902454/2758833
2. https://stackoverflow.com/a/2883923/2758833
SelectedValuePath Documentation:
1. https://learn.microsoft.com/en-us/dotnet/api/system.windows.controls.primitives.selector.selectedvaluepath
SelectedValue updates possible bugs for .NET 4 and .NET 4.5:
1. https://stackoverflow.com/a/247482/2758833

edited Jul 15 '19 at 21:42

MHN

103
2
7

answered Jun 16 '16 at 01:32

Ony

399
6
16

I recommend reading the documentation on ComboBox.SelectedValue instead of just guessing about it. – 15ee8f99-57ff-4f92-890c-b56153 Jun 16 '16 at 03:44
That's the kind of thing I was referring to. Some people try to use `SelectedValue` without setting `SelectedValuePath`. The question you linked to is *an example* of somebody trying to use `SelectedValue` without setting `SelectedValuePath`. The accepted answer to that question totally failed to understand *why* `SelectedValue` wasn't working. People don't read the documentation. I recommend that you read the documentation, rather than posting wrong information on StackOverflow. – 15ee8f99-57ff-4f92-890c-b56153 Jun 16 '16 at 12:47
[Here's the documentation](https://msdn.microsoft.com/en-us/library/system.windows.controls.primitives.selector.selectedvaluepath(v=vs.110).aspx). HTH. – 15ee8f99-57ff-4f92-890c-b56153 Jun 16 '16 at 12:58
This worked for me, i was missing: UpdateSourceTrigger=PropertyChanged – Jon Barker Dec 22 '17 at 17:27

WPF Combobox binding with List

3 Answers3

Linked