R – Silverlight light dropdown

silverlightsilverlight-3.0

I have a Silverlight form that contains a Stack Panel (orientation = vertical) with 10 rows. Each row contains a TextBlock and Textbox control except the last row has a TextBlock and Drowdown.. At the bottom of the control are two buttons. Previous & Continue.

There are 10 items in the Dropdown. When I select a value from the Dropdown, only two of the ten items are showing up. I believe that the remaining items aren't displying because there's some sort of clipping effect going on. Fair enough.

Does Silverlight allow the dropdown control to display upwards (instead of the default down direction)? Will I have to override some rendering capabiliities before the dropdown is rendered to the control or is there a property that allows me to accomplish this functionality?

Best Answer

The Silverlight ComboBox auto aligns the dropdown popup to always be visible whenever possible. all Popup based controls (ComboBox, AutoCompleteBox, DatePicker and TimePicker) all have this feature enabled.

So if there's not enough screen real-estate below the ComboBox to show the dropdown popup, it'll show up above the control. The combobox nesting in the visual tree should not affect the dropdown popup auto alignment. The internal Popup control (inside the ComboBox) ignores the Visual Tree and is nested "above" the visual tree.

If you have specific issues, please share minimal and relevant XAML. Since Keith is on this thread, I think it's safe to say he'll log a bug if needed.

Related Solutions

Binding Silverlight UserControl custom properties to its’ elements

First, set the DataContext on the UserControl using {RelativeSource Self}:

<UserControl x:Class="XWord.Square"  
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"   
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
FontSize="30"   
Width="100" Height="100" 
DataContext="{Binding RelativeSource={RelativeSource Self}}">

Now you can bind the individual elements to the properties of the usercontrol:

<TextBlock x:Name="Label" Grid.Row="0" Grid.Column="1" 
Text="{Binding LabelText}"/>  
<TextBox x:Name="Content" Grid.Row="1" Grid.Column="0" 
Text="{Binding ContentCharacter}" BorderThickness="0" />

For SL 2.0, you'll need to set the DataContext on the UserControl's Loaded event handler.

private void UserControl_Loaded( object sender, RoutedEventArgs e ) {
    LayoutRoot.DataContext = this;
}

R – Out of range error when closing pop-up

I think the problem lies with how you're closing the popup. Are you removing it from the visual tree or just setting its visibility to collapsed?

If (as I think your problem suggests) you're removing it from the visual tree entirely, you may be able to solve the immediate problem by collapsing the visibility of your text boxes first, and then removing the control. That assumes that your code above is being called as a result of a resize (or a potential resize) of the textboxes. Alternately, you could just empty them of content before you remove them also.

As for an Unloaded event, there isn't anything in the framework that'll do that for you. You could write a custom unload method for your control easily enough though, and just use that when you want to remove it.

Best Answer

Related Solutions

Binding Silverlight UserControl custom properties to its’ elements

R – Out of range error when closing pop-up

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