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So I have a longlistselector with textboxes inside. The user can interact with these textboxes, and insert more text. When the text is inserted the textbox expands and the user can continue writing and have an overview.

But when the user gets to the bottom in the longlistselector and starts writing in the last textbox the textbox expands outside the longlistselector. Which means the user has to stop writing and scroll the longlistselector down, and then continue writing.

So the issue is, that when the textbox is in the bottom of the longlistselector and the text expands out of view the longlistselector does not scroll down.

This is my xaml code for the longlistselector

<Grid x:Name="ContentPanel" Margin="12,49,12,0" Grid.RowSpan="2">

        <Grid.RowDefinitions>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <phone:LongListSelector x:Name="ChatList"  Grid.Row="0" HorizontalAlignment="Left" Width="456" Padding="0" >
            <phone:LongListSelector.ItemTemplate>
                <DataTemplate>
                    <local:ChatRoomTemplateSelector Content="{Binding}">
                        <local:ChatRoomTemplateSelector.YourSelf>
                            <DataTemplate x:Name="YourSelf">
                                <StackPanel>
                                    <Grid x:Name="YourSelfGrid">
                                        <Grid.RowDefinitions>
                                            <RowDefinition Height="*"/>
                                        </Grid.RowDefinitions>
                                        <UserControl Grid.Row="0">
                                            <Path Data="Data" Fill="LawnGreen" StrokeThickness="0" Stretch="Fill" UseLayoutRounding="True"/>
                                        </UserControl>
                                        <TextBox Background="LawnGreen" Text="{Binding Path=Post, Mode=TwoWay,UpdateSourceTrigger=Explicit}" IsReadOnly="{Binding readOnly}" FontSize="20" Margin="39,10" TextWrapping="Wrap" BorderBrush="LawnGreen" Style="{StaticResource TextBoxStyleYourself}" TextChanged="OnTextBoxTextChanged"/>

                                    </Grid>
                                    <StackPanel Orientation="Horizontal">

                                        <Path Data="Data" Fill="LawnGreen" StrokeThickness="0" Stretch="Fill" UseLayoutRounding="True" Margin="50,-1,0,0"/>

                                        <TextBlock Text="{Binding Name}" FontWeight="Bold" FontSize="25" TextWrapping="Wrap"/>
                                    </StackPanel>
                                </StackPanel>
                            </DataTemplate>
                        </local:ChatRoomTemplateSelector.YourSelf>
                        </local:ChatRoomTemplateSelector>
                </DataTemplate>
            </phone:LongListSelector.ItemTemplate>
        </phone:LongListSelector>

    </Grid>
</Grid>

And I add content to the longlistselector with this snippet of the code

source.Add(new Data() { Name = ChatRoomOverview.userName, User = "YourSelf", readOnly = false, Post = "" });
ChatList.ItemsSource = source;

Edit

I know how to scroll to the last element when starting up and the LLS works fine. But when the user in the last inserted element inputs to much text such that the textbox expands outside of the view I cannot get the LLS to keep the item in view. How do I do this?

4

1 回答 1

0

如果您以编程方式添加项目，您还需要以编程方式确保它们滚动到视图中。您可以使用该LongListSelector.ScrollTo方法执行此操作。
LLS 不会自动将新添加的项目滚动到视图中。

更新：

作为 LLS 问题底部扩展文本框的解决方案。您可以改为执行以下操作：

XAML：

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
    <ScrollViewer x:Name="MyScrollViewer">
        <StackPanel>
        <ItemsControl x:Name="MyItems">
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <TextBlock Style="{StaticResource PhoneTextExtraLargeStyle}"
                                TextWrapping="Wrap"
                                Text="{Binding}" />
                </DataTemplate>
            </ItemsControl.ItemTemplate>
        </ItemsControl>
        <TextBox AcceptsReturn="True"
                    FontSize="36"
                    TextWrapping="Wrap"
                    VerticalScrollBarVisibility="Auto"
                    Text="{Binding}"
                    TextChanged="OnTextChanged"
                    Margin="0,0,0,48" />
        </StackPanel>
    </ScrollViewer>
</Grid>

后面的代码：

public partial class MainPage : PhoneApplicationPage
{
    public MainPage()
    {
        this.InitializeComponent();

        // Some sample existing items
        this.MyItems.ItemsSource = new[] { "one", "two", "three", "four", "five" };
    }

    private void OnTextChanged(object sender, TextChangedEventArgs e)
    {
        // This is a brute force attempt to scroll to the bottom of all content.
        // You may want to be smarter about when this is done, such as when a "\r"
        // is added to the end of the text in the textbox or the text is added
        // such that it forces a new line. Beware text being changed in the middle
        // of a large block of text as may not want that to trigger a scroll to the bottom.
        this.MyScrollViewer.ScrollToVerticalOffset(double.MaxValue);
    }
}

有点粗略，但希望你能明白。

这使用单独的ItemsControl和TextBox内部的 aScrollViewer来模仿 LLS 行为，并且将始终展开保持 TextBox 的底部可见，同时仍允许滚动所有内容。
显然，如果您与 LLS 密切相关，这将不起作用。

于 2013-11-05T14:58:04.880 回答