C# 在 WPF ListView 中以编程方式选择项目
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Select item programmatically in WPF ListView
提问by Paul Prewett
I'm unable to figure out how to select an item programmatically in a ListView.
我无法弄清楚如何在 ListView 中以编程方式选择项目。
I'm attempting to use the listview's ItemContainerGenerator, but it just doesn't seem to work. For example, obj is null after the following operation:
我正在尝试使用列表视图的 ItemContainerGenerator，但它似乎不起作用。比如如下操作后obj为null：
//VariableList is derived from BindingList
m_VariableList = getVariableList();
lstVariable_Selected.ItemsSource = m_VariableList;
var obj =
lstVariable_Selected.ItemContainerGenerator.ContainerFromItem(m_VariableList[0]);
I've tried (based on suggestions seen here and other places) to use the ItemContainerGenerator's StatusChanged event, but to no avail. The event never fires. For example:
我尝试过（基于此处和其他地方的建议）使用 ItemContainerGenerator 的 StatusChanged 事件，但无济于事。事件永远不会触发。例如：
m_VariableList = getVariableList();
lstVariable_Selected.ItemContainerGenerator.StatusChanged += new EventHandler(ItemContainerGenerator_StatusChanged);
lstVariable_Selected.ItemsSource = m_VariableList;
...
void ItemContainerGenerator_StatusChanged(object sender, EventArgs e)
{
//This code never gets called
var obj = lstVariable_Selected.ItemContainerGenerator.ContainerFromItem(m_VariableList[0]);
}
The crux of this whole thing is that I simply want to pre-select a few of the items in my ListView.
整个事情的关键是我只想在我的 ListView 中预先选择一些项目。
In the interest of not leaving anything out, the ListView uses some templating and Drag/Drop functionality, so I'm including the XAML here. Essentially, this template makes each item a textbox with some text - and when any item is selected, the checkbox is checked. And each item also gets a little glyph underneath it to insert new items (and this all works fine):
为了不遗漏任何内容，ListView 使用了一些模板和拖放功能，因此我在此处包含了 XAML。本质上，这个模板使每个项目成为一个带有一些文本的文本框 - 当任何项目被选中时，复选框被选中。每个项目下面还有一个小字形以插入新项目（这一切正常）：
<DataTemplate x:Key="ItemDataTemplate_Variable">
<StackPanel>
<CheckBox x:Name="checkbox"
Content="{Binding Path=ListBoxDisplayName}"
IsChecked="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListViewItem}}, Path=IsSelected}" />
<Image ToolTip="Insert Custom Variable" Source="..\..\Resources\Arrow_Right.gif"
HorizontalAlignment="Left"
MouseLeftButtonDown="OnInsertCustomVariable"
Cursor="Hand" Margin="1, 0, 0, 2" Uid="{Binding Path=CmiOrder}" />
</StackPanel>
</DataTemplate>
...
<ListView Name="lstVariable_All" MinWidth="300" Margin="5"
SelectionMode="Multiple"
ItemTemplate="{StaticResource ItemDataTemplate_Variable}"
SelectionChanged="lstVariable_All_SelectionChanged"
wpfui:DragDropHelper.IsDropTarget="True"
wpfui:DragDropHelper.IsDragSource="True"
wpfui:DragDropHelper.DragDropTemplate="{StaticResource ItemDataTemplate_Variable}"
wpfui:DragDropHelper.ItemDropped="OnItemDropped"/>
So what am I missing? How do I programmatically select one or more of the items in the ListView?
那么我错过了什么？如何以编程方式选择 ListView 中的一项或多项？
采纳答案by Kent Boogaart
Bind the IsSelectedproperty of the ListViewItemto a property on your model. Then, you need only work with your model rather than worrying about the intricacies of the UI, which includes potential hazards around container virtualization.
将 的IsSelected属性绑定ListViewItem到模型上的属性。然后，您只需使用您的模型，而不必担心 UI 的复杂性，其中包括围绕容器虚拟化的潜在危害。
For example:
例如：
<ListView>
<ListView.ItemContainerStyle>
<Style TargetType="ListViewItem">
<Setter Property="IsSelected" Value="{Binding IsGroovy}"/>
</Style>
</ListView.ItemContainerStyle>
</ListView>
Now, just work with your model's IsGroovyproperty to select/deselect items in the ListView.
现在，只需使用模型的IsGroovy属性来选择/取消选择ListView.
回答by Will Eddins
Here would be my best guess, which would be a much simpler method for selection. Since I'm not sure what you're selecting on, here's a generic example:
这是我最好的猜测，这将是一种更简单的选择方法。由于我不确定您在选择什么，这里有一个通用示例：
var indices = new List<int>();
for(int i = 0; i < lstVariable_All.Items.Count; i++)
{
// If this item meets our selection criteria
if( lstVariable_All.Items[i].Text.Contains("foo") )
indices.Add(i);
}
// Reset the selection and add the new items.
lstVariable_All.SelectedIndices.Clear();
foreach(int index in indices)
{
lstVariable_All.SelectedIndices.Add(index);
}
What I'm used to seeing is a settable SelectedItem, but I see you can't set or add to this, but hopefully this method works as a replacement.
我习惯看到的是一个可设置的 SelectedItem，但我看到你不能设置或添加到它，但希望这个方法可以作为替代。
回答by Ahmad
Where 'this' is the ListView instance. This will not only change the selection, but also set the focus on the newly selected item.
其中 'this' 是 ListView 实例。这不仅会改变选择，还会将焦点设置在新选择的项目上。
private void MoveSelection(int level)
{
var newIndex = this.SelectedIndex + level;
if (newIndex >= 0 && newIndex < this.Items.Count)
{
this.SelectedItem = this.Items[newIndex];
this.UpdateLayout();
((ListViewItem)this.ItemContainerGenerator.ContainerFromIndex(newIndex)).Focus();
}
}
