星空雅梦

WPF之DataTemplate

DataTemplate顾名思义，就是数据模板，用来指定数据的表现形式。这对于ItemsControl类的控件尤其有用，可以改变列表项的外观，更具有表现能力。

例如

<Grid>
<Grid.Resources>
<src:Customers x:Key="customers"/>
</Grid.Resources>

<ListBox ItemsSource="{StaticResource customers}" Width="350" Margin="0,5,0,10">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Padding="5,0,5,0"
Text="{Binding FirstName}" />
<TextBlock Text="{Binding LastName}" />
<TextBlock Text=", " />
<TextBlock Text="{Binding Address}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>

<Grid>
    <Grid.Resources>
        <src:Customers x:Key="customers"/>
    </Grid.Resources>

    <ListBox ItemsSource="{StaticResource customers}" Width="350" Margin="0,5,0,10">
        <ListBox.ItemTemplate>
            <DataTemplate>
                <StackPanel Orientation="Horizontal">
                    <TextBlock Padding="5,0,5,0"
          Text="{Binding FirstName}" />
                    <TextBlock Text="{Binding LastName}" />
                    <TextBlock Text=", " />
                    <TextBlock Text="{Binding Address}" />
                </StackPanel>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
</Grid>

上例中通过指定ListBox.ItemTemplate属性来定义子项的显示格式，如果不是列表项，可以通过控件的ContentTemplate属性来指定应用哪个数据模板。

使用起来比较简单，大概分为三步：

1.如果有些属性不是可以直接使用，需要转换的，写转换器，实现IValueConverter接口

2.定义好转换器之后，需要实例化，指定给需要的绑定

3.定义模板，也就是需要的显示格式

4.应用模板，把定义好的模板指定到目标控件的ContentTemplate或者ItemTemplate

看一个完整的例子

1.用来封装的实体类和转换器

class Car
{
public string Automaker { get; set; }
public string Name { get; set; }
public string Year { get; set; }
public string TopSpeed { get; set; }
}

//厂商名称转化为Logo图片
public class AutomakerToLogoPathConverter:IValueConverter
{

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
string uriStr = string.Format(@"images/{0}.jpg",value.ToString());
return new BitmapImage(new Uri(uriStr, UriKind.Relative));
}

public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}

//汽车名称转化为图像
public class NameToPhotoPathConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
string uriStr = string.Format(@"images/{0}.jpg", value.ToString());
return new BitmapImage(new Uri(uriStr, UriKind.Relative));
}

public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}

class Car
    {
        public string Automaker { get; set; }
        public string Name { get; set; }
        public string Year { get; set; }
        public string TopSpeed { get; set; }
    }

    //厂商名称转化为Logo图片
    public class AutomakerToLogoPathConverter:IValueConverter
    {
        
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            string uriStr = string.Format(@"images/{0}.jpg",value.ToString());
            return new BitmapImage(new Uri(uriStr, UriKind.Relative));
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

    //汽车名称转化为图像
    public class NameToPhotoPathConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            string uriStr = string.Format(@"images/{0}.jpg", value.ToString());
            return new BitmapImage(new Uri(uriStr, UriKind.Relative));
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

2.模板及窗体

<Window x:Class="TempaletPractise.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TempaletPractise"
Title="汽车展览" Height="350" Width="623">
<Window.Resources>
<!--Converter-->
<local:AutomakerToLogoPathConverter x:Key="a2l"></local:AutomakerToLogoPathConverter>
<local:NameToPhotoPathConverter x:Key="n2p"></local:NameToPhotoPathConverter>

<!--Data Template for Detail View-->
<DataTemplate x:Key="carDetailViewTemplate">
<Border BorderBrush="Black" BorderThickness="1" CornerRadius="6">
<StackPanel Margin="5">
<Image Width="400" Height="250" Source="{Binding Name, Converter={StaticResource n2p}}"></Image>
<StackPanel Orientation="Horizontal" Margin="5,0">
<TextBlock Text="Name:" FontWeight="Bold" FontSize="20"></TextBlock>
<TextBlock Text="{Binding Name}" FontSize="20" Margin="5,0"></TextBlock>
</StackPanel>
<StackPanel Orientation="Horizontal" Margin="5,0">
<TextBlock Text="Automaker" FontWeight="Bold"></TextBlock>
<TextBlock Text="{Binding Automaker}" Margin="5,0"></TextBlock>
<TextBlock Text="Year" FontWeight="Bold"></TextBlock>
<TextBlock Text="{Binding Year}" Margin="5,0"></TextBlock>
<TextBlock Text="Top Speed" FontWeight="Bold"></TextBlock>
<TextBlock Text="{Binding TopSpeed}" Margin="5,0"></TextBlock>
</StackPanel>
</StackPanel>
</Border>
</DataTemplate>

<!--DataTemplate for Item View-->
<DataTemplate x:Key="carListItemViewTemplate">
<Grid Margin="2">
<StackPanel Orientation="Horizontal">
<Image Source="{Binding Automaker,Converter={StaticResource a2l}}"
Grid.RowSpan="3" Width="64" Height="64"></Image>
<StackPanel Margin="5,0">
<TextBlock Text="{Binding Name}" FontSize="16" FontWeight="Bold"></TextBlock>
<TextBlock Text="{Binding Year}" FontSize="14"></TextBlock>
</StackPanel>
</StackPanel>
</Grid>
</DataTemplate>
</Window.Resources>
<!--窗体的内容-->
<StackPanel Orientation="Horizontal" Margin="5">
<UserControl ContentTemplate="{StaticResource carDetailViewTemplate}"
Content="{Binding SelectedItem, ElementName=listBoxCars}"></UserControl>
<ListBox x:Name="listBoxCars" Width="180" Margin="5,0" ItemTemplate="{StaticResource carListItemViewTemplate}"></ListBox>
</StackPanel>
</Window>

3.指定数据源

private void InitialCarList()
{
List<Car> cars = new List<Car>()
{
new Car(){ Automaker="CADILLAC",Name="CADILLAC1",Year="1990",TopSpeed="340"},
new Car(){ Automaker="Ferrari",Name="Ferrari1",Year="1991",TopSpeed="350"},
new Car(){ Automaker="LAMBORGHINI",Name="LAMBORGHINI1",Year="1992",TopSpeed="360"},
new Car(){ Automaker="PORSCHE",Name="PORSCHE1",Year="1993",TopSpeed="370"}
};

this.listBoxCars.ItemsSource = cars;
}

参考 MSDN 《深入浅出WPF》第11章

ps.今天看到园子编辑推荐的一则新闻，Silverlight开始边缘化，从官方就开始不推了，不知道WPF的命运会怎样，在微软的大船上，只能跟着起伏，不过今天能从ASP.NET转WPF，明天也能从WPF转其他技术，我们从来就不怕这个，毕竟我们学过，想过，用过，他帮助过我们，每种技术都代表了一种思想，技术可以没落，思想却沉淀下来了。