我是新手（这是我的第一篇文章），所以请耐心等待。任何改进都是受欢迎的。
我正在使用.Net 4.0，visual studio 2010编写一个约会调度程序.XAML由一个DataGrid组成，行间隔15分钟，四列，最左边的列用于时间。支持数据由AppointmentRows（ObservableCollection）组成。每行本身由一个ObointvalbeCollection of Appointmnets组成。我使用DragAndDrop作为我的输入方法。
DragAndDrop似乎可以正常工作到单元格级别。可以在数据网格上删除项目，从数据网格中删除项目并在数据网格中重新排列。当在数据网格上删除约会时，第一个DataTrigger将HasAppointment的自定义附加属性设置为true，第二个Trigger通过将DataGridCell背景颜色设置为四种颜色之一来响应此附加属性，具体取决于单元格现在是否为空，包含一个新人，老人或需要特殊管理的人的约会。
问题＃1：
加载DataGrid后，如果先前已使用该单元格，则负责为单元格背景着色的触发器不会触发 - 即使负责设置HasAppointment附加属性的DataTrigger也是如此。也就是说，在加载过程中，当UNUSED单元格上有约会时，所有触发器都能正常工作。但是，一旦触发器在单元格上触发 - 就像第一次加载时或者在其上放置新约会时 - 尽管第一个触发器正确地正确设置了HasAppointment附加属性并且单元格返回到，但是负责背景着色的触发器永远不会触发它包含的第一个约会的第一个背景颜色。要明确：
问题＃2：
在单元格上放下约会后，设置HasAppointment associacted属性的DataTrigger在允许负责着色的Trigger运行之前运行两次。它运行正常，但为什么两次？
问题＃3：
每个小区可能有也可能没有预约。每个具有任命的单元格可能是三个collors中的一个。那么，在不重复每个值的代码的情况下，将多个不同值从转换器返回到DataTrigger的最佳方法是什么？在这个momemt我使用的是Trigger，它在工作时运行良好。
问题＃4：
DataTrigger可以在附加属性上运行，如果可以，绑定是如何设置的？
感谢您对这些事项的任何帮助。
这是XAML：
<Window x:Class="Chaos.Scheduler.Scheduler"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:Chaos.Scheduler"
xmlns:my1="clr-namespace:UpDownCtrls;assembly=UpDownCtrls"
Title="Scheduler" Height="556" Width="1024"
DataContext="{Binding RelativeSource={RelativeSource Self}}"
WindowStartupLocation="CenterScreen">
<!--Resources is a dictionary. so it allows assigning an x:Key value to Styles.-->
<Window.Resources>
<!--Declare converters for custom binding logic-->
<local:RescheduleConverter x:Key="rescheduleConverter" />
<local:ColorConverter x:Key="colorConverter" />
<local:AppointmentConverter x:Key="appointmentConverter" />
<local:WatchApppointmentNamesConverter x:Key="watchAppointmentNamesConverter" />
<!--Show buttons as Red when an edit has occured-->
<Style x:Key="SaveButtonStyle" TargetType="{x:Type Button}">
<Style.Triggers>
<DataTrigger Binding="{Binding HasEdits}" Value="True" >
<Setter Property="Background" Value="Red" />
</DataTrigger>
</Style.Triggers>
</Style>
<!--The XAML will create a "Style" object/instance of type "DataGridCell". Without an x:Key value, this "style" object
will be used as the parent style for all the DataGridCells. -->
<Style TargetType="{x:Type DataGridCell}" x:Key="AppointmentStyle" >
<EventSetter Event="PreviewMouseLeftButtonDown" Handler="DataGridCell_PreviewMouseLeftButtonDown" />
<EventSetter Event="MouseMove" Handler="DataGridCell_MouseMove" />
<EventSetter Event="DragEnter" Handler="DataGridCell_DragEnter" />
<EventSetter Event="Drop" Handler="DataGridCell_Drop" />
<!--Must use Right/LeftButtonUp and not Right/LeftButtonDown as these events are Direct, not tunneling or bubbled.-->
<!--This makes no sense and is probably a bug, but it works-->
<EventSetter Event="PreviewMouseRightButtonUp" Handler="DataGridCell_PreviewMouseRightButtonUp" />
<!--There is no way to replace only part of the visual tree of a control. To change the visual tree of a control you must set the
Template property of the control to its new and COMPLETE ControlTemplate. -->
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DataGridCell}">
<!--Define the DataGridCell content. Bind the Grid control background color to the DataGridCell Style template.
The Background color will be inherited by the textblock (that is within the <Grid> by default).-->
<Grid Background="{TemplateBinding Background}">
<ContentPresenter AllowDrop="True" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
<!--Set default background color for the entire row-->
<Setter Property="Background" Value="Green"/>
<Style.Triggers>
<Trigger Property="local:Scheduler.HasAppointment" Value="true">
<Setter Property="Background">
<Setter.Value>
<MultiBinding Converter="{StaticResource colorConverter}" >
<MultiBinding.Bindings>
<!--Sends the "DataGirdCell" object to the converter-->
<Binding RelativeSource="{RelativeSource Self}"></Binding>
<!--Sends the current "DataGridRow" to the converter. The DataGridRow is the DataContext for the cell -->
<Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type DataGridRow}, AncestorLevel=1}" Path="." />
</MultiBinding.Bindings>
</MultiBinding>
</Setter.Value>
</Setter>
</Trigger>
<!--If the Converter returns True, then the Background will be red for the row-->
<DataTrigger Value="True">
<DataTrigger.Binding>
<!--The DataTrigger is operating on the entire row-->
<MultiBinding Converter="{StaticResource watchAppointmentNamesConverter}" ConverterParameter="0">
<!--send the DataGridCell in effect when the displayname properites change-->
<Binding RelativeSource="{RelativeSource Self}"></Binding>
<!--binding will watch the displaynames for each column. The AppointmentRow is the DataContext for all cells-->
<Binding Path="[0].displayname"></Binding>
<Binding Path="[1].displayname"></Binding>
<Binding Path="[2].displayname"></Binding>
</MultiBinding>
</DataTrigger.Binding>
<!--Any setter here will be applied to the entire row, not just the cell. There MUST HAVE be setter for the Converter to be executed-->
<Setter Property="Background" Value="Red"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid Name="MainGrid">
<!--Set AllowDrop="False" to show the scrollbars as not droppable targets-->
<DataGrid AutoGenerateColumns="False" CellStyle="{StaticResource AppointmentStyle}" ItemsSource="{Binding MySchedule.AppointmentRows}"
HorizontalAlignment="Stretch" Margin="302,47,0,37"
Name="dataGridScheduler" VerticalAlignment="Stretch" Width="688"
AllowDrop="False" SelectionUnit="Cell" SelectionMode="Single"
CanUserReorderColumns="False" CanUserAddRows="False" IsReadOnly="True" >
<!--Must have AllowDrop = True to allow dropping on the cells-->
<DataGrid.RowStyle>
<Style TargetType="{x:Type DataGridRow}">
<Setter Property="AllowDrop" Value="True" />
</Style>
</DataGrid.RowStyle>
<DataGrid.Columns>
<!--{Binding /, Path=[0].displayname} is binding to the current item of the collection, the appointment row,
with index of 0, the appointment, and shows the property of appointment displayname. The displayname must use the INotifyPropertyChanged interface-->
<DataGridTextColumn Binding="{Binding time}" Header="Time" Width="58" IsReadOnly="True" />
<DataGridTextColumn Binding="{Binding /, Path=[0].displayname}" Header="Name" Width="240*" />
<DataGridTextColumn Binding="{Binding /, Path=[1].displayname}" Header="Name" Width="240*" />
<DataGridTextColumn Binding="{Binding /, Path=[2].displayname}" Header="Name" Width="240*" />
</DataGrid.Columns>
</DataGrid>
…..........
</Window>
以下是代码隐藏：
#region Attached Property HasAppointment
// Attached properties are added to the control, not the data being displayed, and used by the XAML directly.
// Example useage in XAML: <Trigger Property="local:Scheduler.HasAppointment" Value="True">
// The attached property template is obtained by typing <propa> tab tab into the code-behind.
public static Boolean GetHasAppointment(DependencyObject obj)
{
return (Boolean)obj.GetValue(HasAppointmentProperty);
}
public static void SetHasAppointment(DependencyObject obj, Boolean value)
{
obj.SetValue(HasAppointmentProperty, value);
}
// Using a DependencyProperty as the backing store for HasAppointment. This enables animation, styling, binding, etc...
public static readonly DependencyProperty HasAppointmentProperty =
DependencyProperty.RegisterAttached("HasAppointment", typeof(Boolean), typeof(Scheduler), new UIPropertyMetadata(false));
#endregion
/* Converters apply custom logic to the XAML Bindings */
/// <summary>
/// Tests the DataGridCell for a displayname. Returns false for no displayname, true for a display name.
/// </summary>
[ValueConversion(typeof(String), typeof(Boolean))]
public class AppointmentConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
String displayname = value as String;
if (string.IsNullOrEmpty(displayname))
return false;
return true;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
/// <summary>
/// Label the reschedule shape with "Reschedule Appointment" or the patient name.
/// </summary>
[ValueConversion(typeof(Appointment), typeof(String))]
public class RescheduleConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
Appointment apt = value as Appointment;
if (apt.displayname == null) return "Reschedule Appointment";
else return apt.displayname;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
/* Color a grid cell based on appointment type and patient history */
public class ColorConverter : IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (values[1] is DataGridRow)
{
// The "cell" tells nothing about its contents, only its location in the grid, its column name and column position.
// The datacontext comes from the datagrid row.
DataGridCell cell = (DataGridCell)values[0];
if (cell.Column.DisplayIndex > 0)
{
Boolean hasappointment = Scheduler.GetHasAppointment(cell);
// the object "row" is of type AppointmentRow.
DataGridRow row = (DataGridRow)values[1];
// gets the physical row number of this row in the grid.
int rowIndex = row.GetIndex();
// SortMemberPath returns: "time", "[0].displayname", " "[1].displayname", "[2].displayname"
string columnName = cell.Column.SortMemberPath;
Appointment appointment = ((AppointmentRow)row.Item)[cell.Column.DisplayIndex - 1] as Appointment;
if (null != appointment.displayname)
{
if ((appointment.type & AppointmentType.Excision) == AppointmentType.Excision)
{
// return new SolidColorBrush(Colors.Red);
return Brushes.Red;
}
else if (null == appointment.lastvisit)
{
// return new SolidColorBrush(Colors.Yellow);
return Brushes.Yellow;
}
}
}
}
// return System.Windows.SystemColors.AppWorkspaceColor;
return new SolidColorBrush(Colors.White);
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
/// <summary>
/// Set the HasAppointment flag for all cells in the AppointmentRow.
/// For some reason, this routine will process the entire row twice on a drop. I suspect setting the HasAppointment flag forces the
/// second processeing as the "cell" object itself maybe changed.
/// [0] = DataGridCell
/// [1] = AppointmentRow[0].displayname
/// [2] = AppointmentRow[1].displayname
/// [3] = AppointmentRow[2].displayname
/// </summary>
public class WatchApppointmentNamesConverter : IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
DataGridCell cell = values[0] as DataGridCell;
if (!String.IsNullOrWhiteSpace((string)values[1]))
{
if (cell.Column.DisplayIndex == 1)
Scheduler.SetHasAppointment(cell, true);
}
else
{
if (cell.Column.DisplayIndex == 1)
Scheduler.SetHasAppointment(cell, false);
}
if (!String.IsNullOrWhiteSpace((string)values[2]))
{
if (cell.Column.DisplayIndex == 2)
Scheduler.SetHasAppointment(cell, true);
}
else
{
if (cell.Column.DisplayIndex == 2)
Scheduler.SetHasAppointment(cell, false);
}
if (!String.IsNullOrWhiteSpace((string)values[3]))
{
if (cell.Column.DisplayIndex == 3)
Scheduler.SetHasAppointment(cell, true);
}
else
{
if (cell.Column.DisplayIndex == 3)
Scheduler.SetHasAppointment(cell, false);
}
// need to return false or will force background to red.
return false;
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
答案 0 :(得分：0)
我仍然无法弄清楚如何在附加属性上使用（或者如果它们起作用）触发器。我肯定想看看如何。与此同时，我发现这很容易解决我的大部分问题：
<DataGridTextColumn.ElementStyle>
<Style TargetType="{x:Type TextBlock}">
<Setter Property="Background" >
<Setter.Value>
<MultiBinding Converter="{StaticResource colorTextConverter}">
<Binding RelativeSource="{RelativeSource Mode=Self}" Path="Text" />
<Binding RelativeSource="{RelativeSource Mode=FindAncestor,AncestorType=DataGridCell}" Path="." />
</MultiBinding>
</Setter.Value>
</Setter>
</Style>
</DataGridTextColumn.ElementStyle>
</DataGridTextColumn>
在这种情况下，简单绑定可以正确地监视显示的变化 - 触发器会错过。