Question

I have been trying to do this for ages and having no joy whatsoever.

I have a ribbon window of the following hierarchy:

• MainWindow
  • MainContent (Tab Control)
    • TabContainerViewModel
      • ViewModelBase

View model base has an ObservableCollection of tabs type ViewModelBase. The Tab Control itself is binding fine to these, displaying appropriate view models. I have 2 problems however, I want a “NotepadView” (Of type viewmodelbase) to be replicated numerous times (one view many view models).

At the minute, I have 4 views (NotePadViewModelx where x is 1-4) with corresponding viewmodels, this is because each view had the same text per tab. Now I have individual views per tab.

When I type into tab 1 and switch to tab 2, I lose what I typed in tab one when I click back.

Could somebody help to provide me with a solution to these problems?

• One NotepadView for multiple instances of the ViewModel
• Keeping information when tabs change

Many thanks in advance.

Answer 1

I moved the Header and Text properties into ViewModelBase and then when I add a ViewModelBase as a Tab I used a DataTemplate for the ViewModelBase as I was for the NotePadViewModels with just a textbox.

  <DataTemplate DataType="{x:Type ui:ViewModelBase}">
    <TextBox Text="{Binding Text, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></TextBox>
  </DataTemplate>

As apose to using this:

  <DataTemplate DataType="{x:Type ui:NotepadViewModel}">
      <ui:NotePadView DataContext="{Binding}"/>
  </DataTemplate>
  <DataTemplate DataType="{x:Type ui:NotepadViewModel2}">
      <ui:NotePadView2 DataContext="{Binding}"/>
  </DataTemplate>
  <DataTemplate DataType="{x:Type ui:NotepadViewModel3}">
      <ui:NotePadView3 DataContext="{Binding}"/>
  </DataTemplate>

Thanks to Rachel for a small hint to the problem. Basically on the previous way nothing was actually binding within the datatemplate so it had no reason to keep it as a resource. By adding a default textbox within a datatemplate I can add as many notepads as I want whilst being able to add other views which don’t need a textbox.