Question

这就是我想要完成的事情：

我想要一个支持以Microsoft Visio风格拖放任意数据的画布。我找到了这样做的链接：http://www.codeproject.com/KB/WPF/WPFDiagramDesigner_Part1.aspx

但是，我也想在运行时给画布补水。我发现这篇文章： https://stackoverflow.com/questions/889825/wpf-is-it-possible-to-bind-a-canvass-children-property-in-xaml

其中一个解决方案建议在它自己的Canvas上绘制每个项目，我已经开始工作了。但我无法通过将数据绑定到画布的ItemControl子项来拖放工作。理想情况下，我希望避免使用代码隐藏来执行此操作。是否有使用我拥有的所有XAML解决方案？我的代码如下：

这是我创建的MoveThumb，它是实际移动的控件。

class MoveThumb : Thumb
    {
        public MoveThumb()
        {
            DragDelta += new DragDeltaEventHandler(this.MoveThumb_DragDelta);
        }

        private void MoveThumb_DragDelta(object sender, DragDeltaEventArgs e)
        {
            Control item = this.DataContext as Control;

            if (item != null)
            {
                double left = Canvas.GetLeft(item);
                double top = Canvas.GetTop(item);

                Canvas.SetLeft(item, left + e.HorizontalChange);
                Canvas.SetTop(item, top + e.VerticalChange);                
            }
        }
    }

这是我根据第一个链接定义的xaml模板。

<ControlTemplate x:Key="MoveThumbTemplate" TargetType="{x:Type t:MoveThumb}">
            <Rectangle Fill="Gray"/>
        </ControlTemplate>


        <ControlTemplate x:Key="NodeItemTemplate">
            <Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
                <t:MoveThumb Template="{StaticResource MoveThumbTemplate}"
                Cursor="SizeAll"/>
                <ContentPresenter Content="{TemplateBinding ContentControl.Content}"/>
            </Grid>
        </ControlTemplate>

        <DataTemplate x:Key="nodeTemplate" DataType="Node">            
                <ContentControl Name="NodeItem"
                                Width="50"
                                Height="50"
                                Canvas.Top="50"
                                Canvas.Left="50"
                                Template="{StaticResource NodeItemTemplate}">
                    <Ellipse Fill="Black" IsHitTestVisible="False"/>
                </ContentControl>            
        </DataTemplate>

这是在画布中创建和绑定我的ItemsControl的xaml。

 <ItemsControl ItemsSource="{Binding Path=NodeCollection}" Grid.Row="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
                <ItemsControl.ItemsPanel>
                    <ItemsPanelTemplate>
                        <Canvas Background="Yellow" Width="auto" Height="auto" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" />
                    </ItemsPanelTemplate>
                </ItemsControl.ItemsPanel>
                <ItemsControl.ItemTemplate>

                    <DataTemplate>
                        <ContentControl Name="NodeItem"
                                Width="50"
                                Height="50"
                                Canvas.Top="100"
                                Canvas.Left="100"
                                Template="{StaticResource NodeItemTemplate}">
                            <Ellipse Fill="Black" IsHitTestVisible="False"/>
                        </ContentControl>
                    </DataTemplate>

                </ItemsControl.ItemTemplate>
                <ItemsControl.ItemContainerStyle>
                    <Style>
                        <Setter Property="Canvas.Top" Value="{Binding Path=Y}" />
                        <Setter Property="Canvas.Left" Value="{Binding Path=X}" />
                    </Style>
                </ItemsControl.ItemContainerStyle>
            </ItemsControl>

Answer 1

我在做类似事情时发现的问题（水平可拖动时间轴）是每个项目都被包装在ContentPresenter中，然后将它放在画布上，这阻止了拇指的工作。如果你想要一个只读显示器就行了，但是如果你想拖动它就成了一个问题。

解决方案是覆盖GetContainerForItemOverride（）方法。我已经为时间轴本身包含了我的控件模板，样式和XAML。
这个链接对我有帮助。 How to change the default item container for ItemsControl?

    public class Timeline : ItemsControl
        {
            protected override System.Windows.DependencyObject GetContainerForItemOverride()
            {
                return new ContentControl();
            }

            protected override void PrepareContainerForItemOverride(System.Windows.DependencyObject element, object item)
            {
                var control = element as Control;
                if (control != null)
                {
                    var myUri = new Uri("/ResourceDictionary.xaml", UriKind.Relative);
                    var dictionary = Application.LoadComponent(myUri) as ResourceDictionary;

                    if (dictionary != null)
                    {
                        control.Template = (ControlTemplate)dictionary["TimelineElementTemplate"];
                    }

                    control.DataContext = item;
                }
                base.PrepareContainerForItemOverride(element, item);
            }
        }


        <ControlTemplate x:Key="TimelineElementTemplate" TargetType="{x:Type Controls:ContentControl}">
                <Grid DataContext="{Binding RelativeSource={RelativeSource TemplatedParent}}">
                    <TextBlock Text="{Binding Path=DataContext.DebugData}"                        
                               ToolTip="{Binding Path=DataContext.DebugData}"
                               Background="{Binding Path=DataContext.Background}"/>
                    <Control Template="{StaticResource ResizeDecoratorTemplate}" />            
                </Grid>
            </ControlTemplate>

    <Style x:Key="TimelineElementStyle" TargetType="Controls:ContentControl">
        <Setter Property="Canvas.Left">
            <Setter.Value>
                <Binding Path="LeftPos" Mode="TwoWay"/>
            </Setter.Value>
        </Setter>

        <Setter Property="Width">
            <Setter.Value>
                <Binding Path="Width" Mode="TwoWay"/>
            </Setter.Value>
        </Setter>         
    </Style>

<Style x:Key="TimelineStyle" TargetType="ItemsControl">
    <Setter Property="ItemsPanel">
        <Setter.Value>
            <ItemsPanelTemplate>
                <Canvas Background="LightGray"></Canvas>
            </ItemsPanelTemplate>
        </Setter.Value>
    </Setter>
</Style>


    <Controls:Timeline Style="{StaticResource TimelineStyle}" 
                               DataContext="{StaticResource timelineViewModel}"   
                               ItemContainerStyle="{StaticResource TimelineElementStyle}"
                               ItemsSource="{Binding ListOfTimelineElements}"
                               HelperClasses:DragDropHelper.IsDragSource="False" 
                               HelperClasses:DragDropHelper.IsDropTarget="True" 
                               HelperClasses:SizeObserver.Observe="True"                 
                               HelperClasses:SizeObserver.ObservedWidth="{Binding TotalWidth, Mode=OneWayToSource}" 
                               BorderBrush="Black" 
                               BorderThickness="1">

            </Controls:Timeline>

WPF：在运行时使用可拖动控件的水合画布

1 个答案: