更新TextBlock绑定不起作用

时间:2014-07-16 13:16:53

标签: c# wpf mvvm data-binding datatemplate

我有关于数据绑定的问题! 我正在为“节点编辑器”编写代码,其中包含一些(不同的)节点。 我使用 BaseViewModel 类派生自 INotifyPropertyChanged

有一个'base' NodeViewModel (源自它),带有 ObservableCollection 和其他属性,比如Node的 Name 属性。它的实现看起来像这样:

(在公共类NodeViewModel:BaseViewModel 中):

protected String mName = String.Empty;

public String Name {
    get { return mName; }
    set {
        if (mName == value) {
            return;
        }
        mName = value;
        OnPropertyChanged("Name");
    }
}

使用 OnPropertyChanged 处理程序,如下所示:

(在 BaseViewModel 中)

protected virtual void OnPropertyChanged(string propertyName) {
    if (PropertyChanged != null) {
        PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
    }
}

现在我还有一个来自 NodeViewModel RoomViewModel

我使用另一个不同的ViewModel来调用 RoomCollectionViewModel 来对某些房间进行分组。 现在当我为我的roomcollection添加一个房间(通过在它们之间绘制连接)时,我测试了所有连接房间的相同名称。

如果集合中存在已连接的房间,并且房间名称相同(例如“新房间”),我想将这两个房间的名称更改为例如“新房间#1”和“新房间#2”。到目前为止没问题。

每个节点控件(使用 DataTemplates 创建并将 DataContext 设置为ViewModel)包含一个显示节点名称的TextBlock(已修改的)。

这就是问题所在:

我使用修改后的Textblock,因为我希望能够通过双击来修改节点的名称。这完全有效,只有当我在Code中修改RoomViewModel的名称时,这个(修改过的)TextBlock才会更新。

奇怪的是: 当我的代码重命名集合中两个同名的房间时,然后双击可编辑的TextBlock(在该过程中转换为TextBox),我已经看到修改后的Text。所以我假设我的DataBinding和我的代码是正确的,只是没有完成:)

那么如何强制更新我的 EditableTextBlock ,Text(DependencyProperty)似乎正确更新...

我希望你明白我的问题是什么!谢谢你的帮助。

更新1 这是我的EditableTextBlock的XAML代码(它来自这里:http://www.codeproject.com/Articles/31592/Editable-TextBlock-in-WPF-for-In-place-Editing

<UserControl x:Class="NetworkUI.EditableTextBlock"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         xmlns:local="clr-namespace:NetworkUI"
         mc:Ignorable="d" 
         d:DesignHeight="60" d:DesignWidth="240" x:Name="mainControl">
<UserControl.Resources>
    <DataTemplate x:Key="EditModeTemplate">
        <TextBox KeyDown="TextBox_KeyDown" Loaded="TextBox_Loaded" LostFocus="TextBox_LostFocus"
                 Text="{Binding ElementName=mainControl, Path=Text, UpdateSourceTrigger=PropertyChanged}"
                 Margin="0" BorderThickness="1" />
    </DataTemplate>
    <DataTemplate x:Key="DisplayModeTemplate">
        <TextBlock Text="{Binding ElementName=mainControl, Path=FormattedText}" Margin="5,3,5,3" MouseDown="TextBlock_MouseDown" />
    </DataTemplate>

    <Style TargetType="{x:Type local:EditableTextBlock}">
        <Style.Triggers>
            <Trigger Property="IsInEditMode" Value="True">
                <Setter Property="ContentTemplate" Value="{StaticResource EditModeTemplate}" />
            </Trigger>
            <Trigger Property="IsInEditMode" Value="False">
                <Setter Property="ContentTemplate" Value="{StaticResource DisplayModeTemplate}" />
            </Trigger>
        </Style.Triggers>
    </Style>
</UserControl.Resources>

这是代码隐藏文件:

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace NetworkUI {
/// <summary>
/// Interaction logic for EditableTextBlock.xaml
/// </summary>
public partial class EditableTextBlock : UserControl {
    #region Dependency Properties, Events
    public static readonly DependencyProperty TextProperty =
        DependencyProperty.Register("Text", typeof(String), typeof(EditableTextBlock),
        new FrameworkPropertyMetadata("", FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
    public static readonly DependencyProperty IsEditableProperty =
        DependencyProperty.Register("IsEditable", typeof(Boolean), typeof(EditableTextBlock), new PropertyMetadata(true));
    public static readonly DependencyProperty IsInEditModeProperty =
        DependencyProperty.Register("IsInEditMode", typeof(Boolean), typeof(EditableTextBlock), new PropertyMetadata(false));
    public static readonly DependencyProperty TextFormatProperty =
        DependencyProperty.Register("TextFormat", typeof(String), typeof(EditableTextBlock), new PropertyMetadata("{0}"));
    #endregion ///Dependency Properties, Events


    #region Variables and Properties
    /// <summary>
    /// We keep the old text when we go into editmode
    /// in case the user aborts with the escape key
    /// </summary>
    private String oldText;
    /// <summary>
    /// Text content of this EditableTextBlock
    /// </summary>
    public String Text {
        get { return (String)GetValue(TextProperty); }
        set { SetValue(TextProperty, value); }
    }
    /// <summary>
    /// Is this EditableTextBlock editable or not
    /// </summary>
    public Boolean IsEditable {
        get { return (Boolean)GetValue(IsEditableProperty); }
        set { SetValue(IsEditableProperty, value); }
    }
    /// <summary>
    /// Is this EditableTextBlock currently in edit mode
    /// </summary>
    public Boolean IsInEditMode {
        get {
            if (IsEditable)
                return (Boolean)GetValue(IsInEditModeProperty);
            else
                return false;
        }
        set {
            if (IsEditable) {
                if (value)
                    oldText = Text;
                SetValue(IsInEditModeProperty, value);
            }
        }
    }
    /// <summary>
    /// The text format for the TextBlock
    /// </summary>
    public String TextFormat {
        get { return (String)GetValue(TextFormatProperty); }
        set  {
            if (value == "")
                value = "{0}";
            SetValue(TextFormatProperty, value);
        }
    }
    /// <summary>
    /// The formatted text of this EditablTextBlock
    /// </summary>
    public String FormattedText {
        get { return String.Format(TextFormat, Text); }
    }
    #endregion ///Variables and Properties


    #region Constructor
    /// <summary>
    /// Default constructor for the editable text block
    /// </summary>
    public EditableTextBlock() {
        InitializeComponent();
        Focusable = true;
        FocusVisualStyle = null;
    }
    #endregion ///Constructor


    #region Methods, Functions and Eventhandler
    /// <summary>
    /// Invoked when we enter edit mode
    /// </summary>
    /// <param name="sender">Sender</param>
    /// <param name="e">Event arguments</param>
    void TextBox_Loaded(object sender, RoutedEventArgs e) {
        TextBox txt = sender as TextBox;
        /// Give the TextBox input focus
        txt.Focus();
        txt.SelectAll();
    }
    /// <summary>
    /// Invoked when we exit edit mode
    /// </summary>
    /// <param name="sender">Sender</param>
    /// <param name="e">Event arguments</param>
    void TextBox_LostFocus(object sender, RoutedEventArgs e) {
        IsInEditMode = false;
    }
    /// <summary>
    /// Invoked when the user edits the annotation.
    /// </summary>
    /// <param name="sender">Sender</param>
    /// <param name="e">Event arguments</param>
    void TextBox_KeyDown(object sender, KeyEventArgs e) {
        if (e.Key == Key.Enter) {
            IsInEditMode = false;
            e.Handled = true;
        }
        else if (e.Key == Key.Escape) {
            IsInEditMode = false;
            Text = oldText;
            e.Handled = true;
        }
    }
    /// <summary>
    /// Invoked when the user double-clicks on the textblock
    /// to edit the text
    /// </summary>
    /// <param name="sender">Sender (the Textblock)</param>
    /// <param name="e">Event arguments</param>
    private void TextBlock_MouseDown(object sender, MouseButtonEventArgs e) {
        if (e.ClickCount == 2)
            IsInEditMode = true;
    }
    #endregion ///Methods, Functions and Eventhandler

}

感谢您的帮助!

更新2

我更改了以下代码行:

<TextBlock Text="{Binding ElementName=mainControl, Path=FormattedText}" Margin="5,3,5,3" MouseDown="TextBlock_MouseDown" />

为:

<TextBlock Text="{Binding ElementName=mainControl, Path=Text}" Margin="5,3,5,3" MouseDown="TextBlock_MouseDown" />

现在它正在运作!

我没有首先使用FormattedText看到TextBlock!唉,非常感谢,现在一切都完美无缺!

1 个答案:

答案 0 :(得分:0)

正如 Lee O。所提出的那样,问题确实是我的EditableTextBlock控件的绑定属性。

TextBlock使用了我的Binding更新的 FormattedText 属性。现在我将Text属性用于TextBlock和TextBox控件。

我只是从我的EditableTextBlock中删除了FormattedText属性以及TextFormatProperty(DependencyProperty)和TextFormat属性,因为我没有计划使用它们。

再次感谢你!