我正在尝试自己学习WPF,这有点困难。我需要知道如何通过绑定设置附加属性的值。附加属性Grid.Row和Grid.RowSpan是绑定的目标,而不是源。在StackOverflow上已经提出了类似的问题,但是他们被真正了解WPF的人询问和回答,或者他们涉及价值转换器等并发症。我还没有找到适合我并且理解的答案。
在这种情况下,我有一个表示全天计划的网格,我想向其添加事件。每个事件将从特定网格行开始并跨越多个行,具体取决于事件的开始时间和持续时间。我的理解是您必须使用依赖项属性作为绑定源,因此我的事件对象ActivityBlock
具有StartIncrement
和DurationIncrements
依赖项属性来描述它在网格上的位置。
这就是我想要做的全部:通过绑定在网格中创建一个UserControl位置。
我相信我的问题最有可能出现在我的MainWindow XAML中,在网格上错误地设置了绑定。 (请注意,我在构造函数中以编程方式创建网格行,因此不要在下面的XAML中查找它们。)
当我运行我的应用程序时,会创建事件,但它不会显示在网格上的正确位置,就好像Grid.Row和Grid.RowSpan永远不会更新一样。绑定Grid.Row和Grid.RowSpan是不可能的?如果没有,我做错了什么?
这是MainWindow.xaml,我的问题很可能是:
<Window x:Class="DayCalendar.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:DayCalendar"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525" Activated="Window_Activated"
>
<DockPanel LastChildFill="True">
<Rectangle Width="50" DockPanel.Dock="Left"/>
<Rectangle Width="50" DockPanel.Dock="Right"/>
<Grid x:Name="TheDay" Background="#EEE">
<ItemsControl ItemsSource="{Binding Path=Children}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Grid />
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemContainerStyle>
<Style TargetType="ContentPresenter">
<Setter Property="Grid.Row" Value="{Binding Path=StartIncrement}" />
<Setter Property="Grid.RowSpan" Value="{Binding Path=DurationIncrements}" />
</Style>
</ItemsControl.ItemContainerStyle>
</ItemsControl>
</Grid>
</DockPanel>
</Window>
以下是MainWindow的代码隐藏文件:
using System;
using System.Windows;
using System.Windows.Controls;
using DayCalendar.MyControls;
namespace DayCalendar {
public partial class MainWindow : Window {
public MainWindow() {
InitializeComponent();
var rowDefs = TheDay.RowDefinitions;
rowDefs.Clear();
for ( int ix = 0; ix < ( 60 / ActivityBlock.MINUTES_PER_INCREMENT ) * 24; ix += 1 ) {
rowDefs.Add( new RowDefinition() );
}
}
private void Window_Activated( object sender, EventArgs e ) {
if ( m_firstActivation ) {
m_firstActivation = false;
var firstActivity = new ActivityBlock();
var today = DateTime.Now.Date;
var startTime = today.AddHours( 11.5 );
var durationSpan = new TimeSpan( 1, 0, 0 );
firstActivity.SetTimeSpan( startTime, durationSpan );
TheDay.Children.Add( firstActivity );
}
}
private bool m_firstActivation = true;
}
}
这是ActivityBlock代码:
using System;
using System.Windows;
using System.Windows.Controls;
namespace DayCalendar.MyControls {
public partial class ActivityBlock : UserControl {
public int StartIncrement {
get { return ( int ) GetValue( StartIncrementProperty ); }
set { SetValue( StartIncrementProperty, value ); }
}
public int DurationIncrements {
get { return ( int ) GetValue( DurationIncrementsProperty ); }
set { SetValue( DurationIncrementsProperty, value ); }
}
public ActivityBlock() {
InitializeComponent();
}
public void SetTimeSpan( DateTime startTime, TimeSpan duration ) {
int startMinute = startTime.Hour * 60 + startTime.Minute;
int durationMinutes = ( int ) duration.TotalMinutes;
StartIncrement = startMinute / MINUTES_PER_INCREMENT;
DurationIncrements = Math.Max( 1, durationMinutes / MINUTES_PER_INCREMENT );
}
static ActivityBlock() {
var thisType = typeof( ActivityBlock );
var affectsArrangeAndMeasure = FrameworkPropertyMetadataOptions.AffectsArrange | FrameworkPropertyMetadataOptions.AffectsMeasure;
int startIncrementDefault = 0;
StartIncrementProperty = DependencyProperty.Register(
nameof( StartIncrement ),
startIncrementDefault.GetType(),
thisType,
new FrameworkPropertyMetadata( startIncrementDefault, affectsArrangeAndMeasure )
);
int durationIncrementsDefault = 1;
DurationIncrementsProperty = DependencyProperty.Register(
nameof( DurationIncrements ),
durationIncrementsDefault.GetType(),
thisType,
new FrameworkPropertyMetadata( startIncrementDefault, affectsArrangeAndMeasure )
);
}
public const int MINUTES_PER_INCREMENT = 6; // 1/10th of an hour
static public readonly DependencyProperty StartIncrementProperty;
static public readonly DependencyProperty DurationIncrementsProperty;
}
}
相应的XAML并不令人感兴趣,但我会在需要时将其包括在内:
<UserControl x:Class="DayCalendar.MyControls.ActivityBlock"
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:DayCalendar.MyControls"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="300">
<Border BorderThickness="3" BorderBrush="Black" Background="Chartreuse">
<DockPanel LastChildFill="True">
<TextBlock TextWrapping="WrapWithOverflow">Event Description</TextBlock>
</DockPanel>
</Border>
</UserControl>
答案 0 :(得分:1)
可以绑定Grid.Row
这里是一个简单的示例MVVM
,
查看强>
<Window x:Class="WpfApplication3.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="20"/>
<RowDefinition Height="20"/>
<RowDefinition Height="20"/>
</Grid.RowDefinitions>
<TextBlock Text="Hello" Grid.Row="{Binding RowNumber}"></TextBlock>
</Grid>
</Window>
<强>视图模型强>
public class ViewModel
{
public ViewModel()
{
RowNumber = 2;
}
public int RowNumber { get; set; }
}
我已将DataContext
设置为CodeBehind
的视图。如下所示,DataContext
与ViewModel
类相关联。我们可以用不同的方式设置DataContext
。
<强> xaml.cs 强>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new ViewModel();
}
}
启动应用程序时,它会将RowNumber
设置为2,并在第3行显示TextBlock
。稍后您可以通过更新RowNumber
ViewModel
来更改行