如何通过IValueConverter为DataGrid的列绑定样式？
效果：
App.xaml
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<Application xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Class="SilverlightApplication15.App" xmlns:app="clr-namespace:SilverlightApplication15"> <Application.Resources> <app:DemoComparableConverter x:Key="ComparableConverter"/> </Application.Resources> </Application>
Page1.xaml
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<UserControl x:Class="SilverlightApplication15.Page1" 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" mc:Ignorable="d" d:DesignHeight="300" d:DesignWidth="400" xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"> <Grid x:Name="LayoutRoot" Background="White"> <sdk:DataGrid AutoGenerateColumns="False" Name="dataGrid1" > <sdk:DataGrid.Columns> <sdk:DataGridTextColumn Binding="{Binding Caption}" Header="Caption" /> <sdk:DataGridTextColumn Binding="{Binding Value}" Header="Value"/> <sdk:DataGridTemplateColumn Header="Value"> <sdk:DataGridTemplateColumn.CellTemplate> <DataTemplate> <TextBlock Text="{Binding Value}" VerticalAlignment="Center" Style="{Binding Converter={StaticResource ComparableConverter}}" /> </DataTemplate> </sdk:DataGridTemplateColumn.CellTemplate> </sdk:DataGridTemplateColumn> </sdk:DataGrid.Columns> </sdk:DataGrid> </Grid> </UserControl>
PS：这是在2010 RC中生成的代码，发现 DataGrid 的引用不是来自程序集了，而是来自 xmlns:sdk="http://schemas.microsoft.com/winfx/2006/xaml/presentation/sdk"
Page1.xaml.cs
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namespace SilverlightApplication15 { public partial class Page1 : UserControl { public Page1() { InitializeComponent(); this.Loaded +=(sender ,e)=> { this.BindControls(); }; } void BindControls() { ObservableCollection<DemoComparableClass> demos = new ObservableCollection<DemoComparableClass>(); demos.Add( new DemoComparableClass("名称A",101) ); demos.Add(new DemoComparableClass("名称B", 51)); demos.Add(new DemoComparableClass("名称C", 201)); this.dataGrid1.ItemsSource = demos; } } }
其他 class
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using System; using System.Windows; using System.Windows.Controls; using System.Windows.Media; namespace SilverlightApplication15 { public enum Results { Normal , Above , Below } public class DemoComparableClass { public string Caption { get; set; } public int Value { get; set; } public DemoComparableClass(string c , int v) { this.Caption = c; this.Value = v; } public Results Result { get { if (this.Value > 100 && this.Value < 200) { return Results.Normal; } else if (this.Value >= 200) { return Results.Above; } else { return Results.Below; } } } } public class DemoComparableConverter : System.Windows.Data.IValueConverter { public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { if (value is DemoComparableClass) { DemoComparableClass v = (DemoComparableClass)value; if (targetType.Equals(typeof(Style))) { Style s = new Style(typeof(TextBlock)); switch (v.Result) { case Results.Normal: s.Setters.Add(new Setter(TextBlock.ForegroundProperty , new SolidColorBrush(Colors.Brown))); break; case Results.Above: s.Setters.Add(new Setter(TextBlock.ForegroundProperty , new SolidColorBrush(Colors.Red))); s.Setters.Add(new Setter(TextBlock.FontWeightProperty, FontWeights.Bold )); break; case Results.Below: s.Setters.Add(new Setter(TextBlock.ForegroundProperty , new SolidColorBrush(Colors.Green))); break; } return s; } else if (targetType.Equals(typeof(Brush))) { switch (v.Result) { case Results.Normal: return new SolidColorBrush(Colors.Brown); case Results.Above: return new SolidColorBrush(Colors.Red); case Results.Below: return new SolidColorBrush(Colors.Green); } } } return null; } public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { throw new NotImplementedException(); } } }
要实现的功能很简单，就是通过 DemoComparableConverter 让 DataGrid 中的单元格显示出不同的样式，我试了半天，得出几点：
1. DataGridTextColumn 只有一个依赖项属性 FontFamilyProperty ，无法以
- <sdk:DataGridTextColumn Binding="{Binding Value}" Header="Value"
Foreground="{Binding Converter={StaticResource ComparableConverter}}"/>
方式进行绑定；
2. 似乎只能使用 DataGridTemplateColumn ，并对 DataTemplate 中的控件进行 Style、Foreground、Background 等依赖项属性的绑定了；
3. 如果碰上要动态的为DataGrid添加列的情况（如上面的效果图所示，“单价、价格、交货日期”等列是根据用户的选择而决定要不要显示的，可能还会有诸如“运费、管理费、折扣率、税收”等等可供选择的列，又或者是要显示各个代理商在1-12月的销售情况的数据透视表，这些都是动态显示列的例子），则只能通过后台代码为 DataGrid 增加DataGridTemplateColumn ，那么如何在代码中为 DataTemplate 中的控件进行 Style、Foreground、Background 等依赖项属性的绑定？ 目前我是通过加载动态 DataTemplate 来实现，感觉比较麻烦： -
DataGridTemplateColumn col = new DataGridTemplateColumn(); col.Header = header; // header 为表头标题 col.CellTemplate = (DataTemplate)System.Windows.Markup.XamlReader.Load( GetNumericTemplate(propertyName)); // propertyName 为要被绑定的属性名 public string GetDateTemplate(string propertyName) { string template = @" <DataTemplate xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'> <TextBlock Text='{Binding @PropertyName}' Style='{Binding Converter={StaticResource ComparableConverter}}' VerticalAlignment='Center' /> </DataTemplate>"; return template.Replace("@PropertyName", propertyName); }
加载动态 DataTemplate 还可以直接使用 Resources ，但是我不知道该如何动态的指定 propertyName
- col.CellTemplate =(DataTemplate) this.Resources["ADataTemplate"];
不知各位有没有更方便的方法？或者网络上早已有正解~~~~
