ComboBox SelectedValue correctly sets SelectedValue in Viewmodel but not in View

Question

In my Project my selectedvalue sets correctly in viewmodel but my view not sets its selectedvalue

in xaml code:

 <ComboBox ItemsSource="{Binding AllValues}" SelectedValue="{Binding SelectedValue,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Width="150" Margin="5,0,0,0">

in ViewModel:

public Model SelectedValue
        {
            get
            {
                return _model.Value;
            }
            set
            {
                 _model.Value = value;
                if (CVSCollection.View != null)
                    CVSCollection.View.Refresh();
                RaisePropertyChanged("SelectedValue");
            }
        }

score 0 · Answer 1 · answered Nov 01 '12 at 07:23

Try using a ICollectionView in combination with IsSynchronizedWithCurrentItem. The ICollectionView takes care of all your combobox related actions. You could also set the current selected item.

Xaml:

  <ComboBox ItemsSource="{Binding AllValues}"  
                  IsSynchronizedWithCurrentItem="True"
                  Width="150" 
                  Margin="5,0,0,0"/>

ViewModel

using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows.Data;

namespace ComboBoxBinding
{
    public class ViewModelSpike : INotifyPropertyChanged
    {
        private ObservableCollection<Model> _allValues = new ObservableCollection<Model>();
        private Model _selectedValue;

        public ObservableCollection<Model> AllValues
        {
            get { return _allValues; }
            set { _allValues = value; OnPropertyChanged("AllValues");}
        }

        public Model SelectedValue
        {
            get { return _selectedValue; }
            set { _selectedValue = value; OnPropertyChanged("SelectedValue");}
        }

        public ICollectionView ModelsView { get; private set; }

        public ViewModelSpike()
        {
            //First init / load AllValues here...

            ModelsView = CollectionViewSource.GetDefaultView(AllValues);
            ModelsView.CurrentChanged += OnCurrentModelChanged;

            //You can also set the current selected item / initial selected item
            //ModelsView.MoveCurrentTo(DesiredModel from AllValues)
        }

        private void OnCurrentModelChanged(object sender, EventArgs e)
        {
            if (ModelsView.CurrentItem == null) return;
            var selectedValue = ModelsView.CurrentItem as Model;

            if (selectedValue == null) return;

            SelectedValue = selectedValue;

            if (CVSCollection.View != null) CVSCollection.View.Refresh();
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName)
        {
            PropertyChangedEventHandler handler = PropertyChanged;
            if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

hey thnx for reply...I have tried this but its not working for and another issue created with it is CVSCollection.View.Refresh() not refresh my view..@menty — , Nov 02 '12 at 09:06
hmmm, strange. Do you have set a breakpoint into the OnCurrentModelChanged method to see if the modelsview is correct wired? Do you have setup / load the AllValues Collection before attaching the modelsview to it? Do you have set the IsSynchronizedWithCurrentItem property from the combobox to true? The method I descried in my answer is a common way, we wire all our comboboxes, listboxes, etc. like this. — menty, Nov 02 '12 at 09:38
I have solved it by my own as i have set local varible for SelectedValue and then into Constructor set the value of _selectedValue = _model.value.. — , Nov 07 '12 at 07:39

score 0 · Accepted Answer · answered Nov 07 '12 at 07:43

0

I have solved by my own as i have set local variable for selectedvalue as _selectedValue and into constructor i have set _selectedValue..

answered Nov 07 '12 at 07:43

ComboBox SelectedValue correctly sets SelectedValue in Viewmodel but not in View

2 Answers2