如何删除NewItemPlaceholder在TreeView控件WPF [英] How to remove NewItemPlaceholder at TreeView wpf

问题描述

我绑定的ObservableCollection到ListView和我得到在最后{NewItemPlaceholder}行。如何隐藏或删除行？

 ＆LT; TreeView控件的ItemsSource ={结合MyDataToDisplay}＆GT;
 

收藏是这样的​​：

 的ObservableCollection＆LT; MyElement＆GT; MyDataToDisplay
 

解决方案

只需设置一个ItemTemplate在XAML为ListView（在我的例子一个TreeView，其中相同的故障发生），并将其绑定到一个过滤器。这可能是这样的：

 ＆LT; TreeView.ItemTemplate＆GT;
    ＆LT; HierarchicalDataTemplate的ItemsSource ={结合儿童}＆GT;
        ＆LT; ContentControl中含量={结合转换器= {的StaticResource IgnoreNewItemPlaceholderConverter}}/＆GT;
    ＆LT; / HierarchicalDataTemplate＆GT;
＆LT; /TreeView.ItemTemplate>
 

现在你需要添加一个过滤器，转换器级是这样的：

 类IgnoreNewItemPlaceholderConverter：{的IValueConverter
    公共静态只读IgnoreNewItemPlaceholderConverter实例=新IgnoreNewItemPlaceholderConverter（）;

    公共对象转换（对象的值，类型TARGETTYPE，对象参数，System.Globalization.CultureInfo文化）{
        如果（值= NULL和放大器;！＆安培; value.ToString（）=={NewItemPlaceholder}）
            返回DependencyProperty.UnsetValue;
        返回值;
    }

    公共对象ConvertBack（对象的值，类型TARGETTYPE，对象参数，System.Globalization.CultureInfo文化）{
        抛出新的NotImplementedException（）;
    }
}
 

和不要忘记像这样的东西映射此Filterclass静态资源在您的XAML：

 ＆LT;转换器：IgnoreNewItemPlaceholderConverter X：关键=IgnoreNewItemPlaceholderConverter/＆GT;
 

这是由一个DataGrid beeing绑定到同一个数据源，这不是的IsReadOnly =真（写）。如果这还符合你的要求，你也可以尝试让DataGrid中只读或绑定到不同的数据源。

I bind ObservableCollection to ListView and I get {NewItemPlaceholder} line at the end. How can I hide or remove that line?

<TreeView ItemsSource="{Binding MyDataToDisplay}">

Collection looks like:

ObservableCollection<MyElement> MyDataToDisplay

解决方案

Just set an ItemTemplate in the XAML for the ListView (in my example a TreeView, where the same failure happens), and bind it to a filter converter. This could look like this:

<TreeView.ItemTemplate>
    <HierarchicalDataTemplate ItemsSource="{Binding Children}">
        <ContentControl Content="{Binding Converter={StaticResource IgnoreNewItemPlaceholderConverter}}"/>                  
    </HierarchicalDataTemplate>
</TreeView.ItemTemplate>

Now you have to add a Filter-Converter-Class like this:

class IgnoreNewItemPlaceholderConverter : IValueConverter {
    public static readonly IgnoreNewItemPlaceholderConverter Instance = new IgnoreNewItemPlaceholderConverter();

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {
        if (value != null && value.ToString() == "{NewItemPlaceholder}")
            return DependencyProperty.UnsetValue;
        return value;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) {
        throw new NotImplementedException();
    }
}

And don't forget to map this Filterclass a static resource in your XAML with something like this:

<converter:IgnoreNewItemPlaceholderConverter x:Key="IgnoreNewItemPlaceholderConverter"/>

This is caused by a DataGrid beeing bound to the same datasource, that is not "IsReadOnly=True" (writable). If this still fits your requirements, you can also try to make the DataGrid readonly or to bind to a different datasource.

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