Question

This has me stumped – hopefully someone can point out an obvious error. I have a user control that I am adding to a grid in the MainView of my program. Main view is bound to MainViewModel and the usercontrol is bound to CardioVM.

I have used a test label to check that the routing of the user control is correct and all work ok. I have a class named Cardio which has a property of

    List<string> exercises 

I am trying to pass the strings in

Cardio.List<string> exercises 

to a

List<string> CardioList 

in my CardioVM. When debugging

List<string> CardioList 

is getting populated with items from

Cardio.List<string> exercises

but my ComboBox is not displaying the items on screen. Here is xaml for my UserControl and :

<UserControl x:Class="CalendarTest.UserControl1"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300"
         DataContext="{Binding CardioVM, Source={StaticResource Locator}}">
<Grid>
    <ComboBox ItemsSource="{Binding CardioList, Mode=OneWay}" SelectedItem="{Binding SelectedCardio, Mode=TwoWay}"  Height="50"></ComboBox>

</Grid>

and here is the code for my CardioVM:

    public class CardioVM : ViewModelBase
{
    public Cardio cardioItem { get; set; }
    public CardioVM()
    {
        TestLabel = "Tester";
    }

    //Test Label for binding testing
    private string testLabel;

    public string TestLabel
    {

        get { return testLabel; }
        set
        {
            testLabel = value;
            RaisePropertyChanged("TestLabel");
        }
    }

    public CardioVM(string Date, string File)
    {

        cardioItem = new Cardio(File, Date);
        CardioList = new List<string>(cardioItem.exercises);

    }


   private List<string> cardioList;

   public List<string> CardioList
    {

        get { return cardioList; }
        set
        {
            cardioList = value;
            RaisePropertyChanged("CardioList");
        }
    }

   private string _selectedCardio;
   public string SelectedCardio
   {
       get { return _selectedCardio; }
       set
       {
           _selectedCardio = value;
           RaisePropertyChanged("SelectedCardio");
       }

   }

}

}

Not sure where I am going wrong here but any pointers would be much appreciated.

Here is where I thought I was adding in the userControl to a content control bound proprty in my Main view model:

 public void NewTemplateExecute()
    {
        TextHideTab = "Close"; 
       NewTemplateType = ("New " + SelectedExercise + " Exercise Template");
        //Set the message and lists based on the exercise selected plus adds the drop down control
       switch (SelectedExercise)
       {
           case "Cardio":
               ///
               //This is where I thought CardioVM was being added
               ///
               NewTemplateText = "Please choose a cardio exercise from the drop down list to the left. You can then select the duration of the exercise and the intensity. To add another exercise please press the plus button in the right hand corner";
               ExerciseDropDowns = new CardioVM(selectedDateLabel, @"Model\Repository\Local Data\CardioList.txt");

           break;
           case "Weights":
           NewTemplateText = "Please select a exercise type. you can refine your exercises by body area. Then add the number of sets and the reps per set. Add as many exercises as you like - dont forget to set to total duration";

           break;

           case "HIIT":
           NewTemplateText = "HIIT to add";
           break;
       }
       Messenger.Default.Send("NewTemplate");

    }

I had set the datacontext for CardioVM in my Mainwindow xaml as:

<DataTemplate DataType="{x:Type local:CardioVM}">
    <view:UserControl1/>
</DataTemplate>

I presume I have made a mistake in the way that I have hooked up CaridoVM but couldn’t seem to get it to databind unless I sent it through the VM locator

Answer 1

Thanks to nemesv – you were of course spot on. Removed the DataContext from my CardioVM and now just using DataTemplate set in Main view to bind the Cardio view to the ViewModel. I can now call a cardioVM with parameters from the Mainview and it populates my combobox as expected. Seems I nbeeded to touch up on some of the basics of MVVM