从WPF中的列表框中读取项目

Question

I have listbox in WPF C# which contains some entries. Out of those entries, I'll update only single entry. What I want is, When I click on "Done Editing" button, I want to read only the updated(whose text changed) entry instead of all other entries.

My entry name is "Harvest_TimeSheetEntry". I tried below line, but it reads all the entries.

Harvest_TimeSheetEntry h = listBox1.SelectedItem as Harvest_TimeSheetEntry;

Any idea?

Answer 1

I prefer to address the problem by using the SelectedItem property of a ListBox or CurrentItem of a DataGrid and bind it to a property in my ViewModel.

<ListBox ItemsSource="{Binding HarvestTimeSheet}" SelectedItem={Binding CurrentEntry}.../>

<Button Content="Done Editing..." Command="{Binding DoneEditingCommand}"/>

In my ViewModel I have

    private Harvest_TimeSheetEntry _currentHarvest_TimeSheetEntry;
    public Harvest_TimeSheetEntry CurrentHarvest_TimeSheetEntry
    {
        get { return _currentHarvest_TimeSheetEntry; }
        set
        {
            if (_currentHarvest_TimeSheetEntry == value) return;
            _currentHarvest_TimeSheetEntry = value;
            RaisePropertyChanged("CurrentHarvest_TimeSheetEntry");
        }
    }

This is set to the selected item in the ListBox.

My ViewModel provides the code for the button. I'm using MVVM light to easily provide the RelayCommand and RaisePropertyChanged.

    private RelayCommand _doneEditingCommand;
    public RelayCommand DoneEditingCommand
    {
        get { return _doneEditingCommand ?? (_doneEditingCommand = new RelayCommand(HandleDoneEditing, () => true)); }
        set { _doneEditingCommand = value; }
    }

    public void HandleDoneEditing()
    {
        if (CurrentHarvest_TimeSheetEntry != null)
            //Do whatever you need to do.
    }

It's a little more work but you get so much control and flexibility over the flow.