CODEWITHSUNDEEP
wpf
user316117
user316117

Reputation: 8271

Stackpanel Visibility - what am I doing wrong . .

I want to make a ListBox containing StackPanels as its elements. The StackPanels will be created and added at runtime, in the C# code behind. .

The StackPanels will contain some images but at the moment none of the image stuff exists yet, so in this code I just wanted to make sure I could do the mechanics.

My XAML looks like this:

<Grid>        
    <ListBox Name="listBoxImages" BorderBrush="DarkGray" Width="600" Height="300" BorderThickness="3" 
             Margin="0" Padding="0" Background="#FFC0C0C0"/>    
</Grid>

In the C# code-behind I deliberately set a background color of the Listbox different from the one in the XAML to verify I was accessing the ListBox properly in the code-behind. 

listBoxImages.Background = Brushes.Blue;  //just to show I'm accessing it . . .

That part works; the ListBox displays blue.
Then I went to add a StackPanel. Since there's nothing in it yet I gave it a height and width and a different background color, but I don't see anything. So I checked its visibility and it's false. So I tried setting the visibility using System.Windows.Visibility.Visible but it's still false after that. 

    StackPanel myStackPanel = new StackPanel();
    myStackPanel.HorizontalAlignment = HorizontalAlignment.Left;
    myStackPanel.VerticalAlignment = VerticalAlignment.Top;
    myStackPanel.Background = Brushes.Bisque;  // make something visible
    myStackPanel.MinHeight = 50;
    myStackPanel.Width = 50;
    bool bResult = myStackPanel.IsVisible;
    myStackPanel.Visibility = System.Windows.Visibility.Visible;
    bResult = myStackPanel.IsVisible;
    myStackPanel.Margin = new Thickness(10); 
    listBoxImages.Items.Add(myStackPanel);

Why is the StackPanel visibility false and is that the reason why I don't see it after adding it to the ListBox? (I'm sorry if this is a noob question)

Upvotes: 0

Views: 261

Answers (2)

kidshaw
kidshaw

Reputation: 3451

Listbox is better populated with an items template. If you want to add arbitrary controls of different types, just use a stack panel.

Upvotes: 0

Rohit Vats
Rohit Vats

Reputation: 81243

IsVisible is set to true when it gets rendered on UI.

You can verify by hooking to Loaded event and see value of IsVisible in it by putting breakpoint on the handler.

myStackPanel.Loaded += (s, e) => bResult = myStackPanel.IsVisible;

Also, I verified with your posted code and can see StackPanel rendered on UI.

More verbose definition:

    .........
    listBoxImages.Items.Add(myStackPanel);
    myStackPanel.Loaded += new RoutedEventHandler(myStackPanel_Loaded);
}

void myStackPanel_Loaded(object sender, RoutedEventArgs e)
{
    bool isVisible = (sender as StackPanel).IsVisible;
}

Upvotes: 1

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