将值从代码后面绑定到wpf中的datatemplate控件

Question

I'm new to wpf, I created a listbox it will create a dynamic listitems,Here I used datetemplate which contains two controls that is two textblocks, one textblocks contains binding a values form combobox(which is string datatype),The other one is, bind a value from code bind.

XAML

<ListBox ItemsSource="{Binding obj}"   HorizontalContentAlignment="Left"  x:Name="lstbxindex" SelectionMode="Extended" Foreground="White" FontSize="20px" Height="201" BorderBrush="#555555" Margin="80,40,0,0" VerticalAlignment="Top" Width="282" Background="#555555" >
    <ListBox.ItemTemplate>
            <DataTemplate>
            <StackPanel Orientation="Horizontal" Margin="5" >
                <TextBlock Height="40px" Width="80px" Text="{Binding roundedhourvalue, FontSize="24" Background="#555555"  Foreground="White"></TextBlock>
                <TextBlock x:Name="items"  Text="{Binding}" Margin="35,0,0,0"></TextBlock>
            </StackPanel>
        </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

C# (Roundedhour.cs)

public class Roundedhour
{
    public string hourvalue { get; set; }

    public override string ToString()
    {
       return string.Format("{0}", hourvalue);
    }
} 

In this class create a property for hourvalue. For this class I created a object in codebehind file which I mentioned below.create a object and assign a value for hourvalue variable.

C# (Code Behind)

{
    if (dispatcherTimer1.Interval == TimeSpan.FromSeconds(15))
    {
        //lstbxindex.Items.Add(lstbxindex.SelectedItem.ToString());

        string hrvalue = Convert.ToString(hrvalueinitially);  

        obj = new Roundedhour();
        obj.hourvalue = Convert.ToString(hrvalueinitially);

        string roundedhourvalue =obj.hourvalue;

        this.DataContext = this;


        //lblprojectAhr.Content = string.Join(",", hrvalueinitially + "" + "hr");
    }
}

Here, I created a object for Rounderhour class.Assign values to that property hour value. But I cannot be bind a value from codebind to XAML page.

Answer 1

Your ItemsSource should be of an CollectionType .

ListBox ItemsSource="{Binding obj}" 

You should also start to give your variables and properties meaningful names. That makes it easier to read your code later o n.

The second Problem is in your Binding itself.

You are binding like this: Text="{Binding roundedhourvalue}

So WPF is expecting a property roundedhourvalue on obj .

But as shown in your CodeBehind there is only obj.hourvalue .

So change your Binding to Text="{Binding hourvalue}

Check your Output-Window for details.

NOTE:

string roundedhourvalue = obj.hourvalue;

has no getter and is not accsessible since its private .

NOTE : You either use a Binding OR your set the ItemsSource in CodeBehind.

---

Try it like this:

Just remove all the formatting and stuff:

<ListBox ItemsSource="{Binding RoundedHours}" x:Name="ListBox">
    <ListBox.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal" Margin="5" >
               <TextBlock Text="{Binding hourvalue}"></TextBlock>                   
            </StackPanel>
       </DataTemplate>
    </ListBox.ItemTemplate>
</ListBox>

And change your code-behind to this:

    private void UpdateDataContext(object hrvalueinitially)
    {
        List<Roundedhour> hours = new List<Roundedhour>();
        hours.Add(new Roundedhour()
        {
            hourvalue = hrvalueinitially.ToString()
        });

        //Set the ItemsSource in code: => remove your ItemsSource Binding from XAML
        listBox.ItemsSource = hours;
    }

OR your can use an 'MVVM' approach:

    public class MyViewModel : INotifyPropertyChanged
    {
        //IMPLEMENT INotifyPropertyChanged HERE PLS

        public ObservableCollection<RoundedHour> Collection { get; set; } = new ObservableCollection<RoundedHour>();

        private void AddToCollection(object hrvalueinitially)
        {
            Collection.Add(new RoundedHour()
            {
                hourvalue = hrvalueinitially.ToString()
            });
            OnPropertyChanged("Collection");
        }

        //Make sure to set your Windows DataContext to an Instance of this Class
    }

Answer 2

Assign XAML object's "ItemsSource" property with your binding variable.

Also it's totally wrong binding object's itself into object's property like

this.DataTemplate = this;

Use:

List<yourobject> bindingObjectList = new List<yourobject>();
// insert your objects into the list
this.ItemsSource = bindingObjectList;

Here you can find an example:

Grid & Pivot Binding Example for multiple DataTemplates