How does WPF obtain the entry control based on data items-ItemContainerGenerator

How does WPF obtain the entry control based on data items-ItemContainerGenerator

I. Method:

ContainerFromIndex: return the container of the items in the specified index in ItemCollection.

ContainerFromItem: return the container (entry control such as ComboxItem) corresponding to the specified item ).

Equals (Object): determines whether the specified Object is equal to the current Object.

Finalize: allows objects to try to release resources and clean up objects before they are recycled.

GeneratorPositionFromIndex: gets the position where the item is generated at the specified index.

GetHashCode: Used as a hash function of a specific type.

GetType: Get the Type of the current instance.

IndexFromContainer: gets the index of an item with the specified generated container.

IndexFromGeneratorPosition: returns the index mapped to the specified GereratorPosition.

ItemFromContainer: returns the corresponding item generated by the specified container.

 

Ii. Events

ItemsChanged: occurs when items in the set change.

 

3. Note

 

Note the association between the ItemContainerGenerator class maintenance item Control and Its item container. If a control has an associated ItemContainerGenerator, it can be retrieved through its properties.

You can use ItemContainerGenerator and index-based items to retrieve items or specify data items to retrieve containers. For example, if you have a Combox bound to data and want to obtain a ComboxItem based on its index, you can use the ContainerFromIndex method. To retrieve data items, use the ItemFromContainer method.

Iv. Example:

 

C #:

public MyTest(){    InitializeComponent();    string[] myCollection= new string[]{"Item 1", "Item 2", "Item 3", "Item 4", "Item 5"};   myCombox.DataContext = myCollection; } 

static int count = 1; 
private void Button_Click(object sender, RoutedEventArgs e) 
{ 
  ConmboxItem item = (ComboxItem)

  myCombox.ItemContainerGenerator.ContainerFromIndex(3); 
  item.IsExpanded = true; if (count < 5) { item.Items.Add("Child " + count.ToString()); count++; } 
}

Xaml:

<StackPanel x:Name="LayoutRoot" Background="White">    <Combox x:Name="myCombox" Width="200" ItemsSource="{Binding}" Margin="5"/>    <Button Content="Add Child to Item 4" Width="150" Click="Button_Click"/></StackPanel>