我们正在将解决方案从Winforms迁移到WPF。我们有定制的XML定义,用于在运行时构建窗体。
由于XAML是基于XML的,我们能否使用XAML定义一个HelloWorldWindow.xml文件,并且可以在WPF应用程序中加载它而不需要任何CSharp文件的代码后台?我们将在运行时附加代码后台钩子。
如何在运行时附加代码后台?
由于XAML是基于XML的,我们能否使用XAML定义一个HelloWorldWindow.xml文件,并且可以在WPF应用程序中加载它而不需要任何CSharp文件的代码后台?我们将在运行时附加代码后台钩子。
如何在运行时附加代码后台?
使用此XAML创建一个名为Tempwin.xml的XML文件:
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Height="300" Width="300" Background="Transparent" >
<Border Background="Black" CornerRadius="10" BorderThickness="4" BorderBrush="RoyalBlue">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<TextBlock Text="Sample Text" Foreground="White" Margin="2"></TextBlock>
<TextBox Grid.Row="1" Margin="5"> </TextBox>
<TextBlock Text="Sample Text 1" Grid.Row="2" Foreground="White" Margin="2"></TextBlock>
<TextBox Grid.Row="3" Margin="5"></TextBox>
<Ellipse Fill="Red" Height="100" Width="100" Grid.Row="4" Margin="0,10,0,0"></Ellipse>
</Grid>
</Border>
使用下面的XAML创建一个WPF示例应用程序:
<Window x:Class="WpfApplication12.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="600" Width="600">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
<Button Height="25" Width="100" Margin="2" Click="Button_Click"> Show Content</Button>
<Grid x:Name="content" Grid.Row="1" Margin="2">
</Grid>
</Grid>
将下面的 C# 代码粘贴到 Button_Click 的代码后台
StreamReader mysr = new StreamReader(@"D:\Tempwin.xml");
FrameworkElement rootObject = XamlReader.Load(mysr.BaseStream) as FrameworkElement;
content.Children.Add(rootObject);
如果您想在运行时加载XAML,则不能在XAML文件中添加任何代码。因此,在创建XML之前,我已经删除了x:Class属性。
事件挂钩....
<UserControl
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Height="300" Width="300" Background="Transparent" >
<Border Background="Black" CornerRadius="10" BorderThickness="4" BorderBrush="RoyalBlue">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
<RowDefinition Height="Auto"></RowDefinition>
</Grid.RowDefinitions>
<TextBlock Text="Sample Text" Foreground="White" Margin="2"></TextBlock>
<TextBox Grid.Row="1" Margin="5"> </TextBox>
<TextBlock Text="Sample Text 1" Grid.Row="2" Foreground="White" Margin="2"></TextBlock>
<TextBox Grid.Row="3" Margin="5"></TextBox>
<Ellipse Fill="Red" Height="100" Width="100" Grid.Row="4" Margin="0,10,0,0"></Ellipse>
<Button Grid.Row="5" Height="25" Content="Event added at Runtime" x:Name="btnTest"></Button>
</Grid>
</Border>
Button ButtoninXAML;
private void Button_Click(object sender, RoutedEventArgs e)
{
StreamReader mysr = new StreamReader(@"D:\Tempwin.xml");
FrameworkElement rootObject = XamlReader.Load(mysr.BaseStream) as FrameworkElement;
ButtoninXAML = LogicalTreeHelper.FindLogicalNode(rootObject, "btnTest") as Button;
ButtoninXAML.Click += new RoutedEventHandler(Button_Click1);
content.Children.Add(rootObject);
}
private void Button_Click1(object sender, RoutedEventArgs e)
{
MessageBox.Show("Added At Runtime");
}
string text = @"<TextBlock Text='test' xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' />";
// Convert to stream
// You can also just stream the xaml from a file, using a FileStream
MemoryStream stream = new MemoryStream(ASCIIEncoding.UTF8.GetBytes(text));
// Convert to object
TextBlock block = (TextBlock)System.Windows.Markup.XamlReader.Load(stream);
//... now you can put that TextBlock somewhere, for example in your main Window
XamlReader.Parse
直接解析字符串,而不需要创建一个 MemoryStream。 - Bip901我已经成功在运行时加载了XAML,以下是一个简短的示例:
Grid grd = new Grid();
var grdEncoding = new ASCIIEncoding();
var grdBytes = grdEncoding.GetBytes(myXAML);
grd = (Grid)XamlReader.Load(new MemoryStream(grdBytes));
Grid.SetColumn(grd, 0);
Grid.SetRow(grd, 0);
parentGrid.Children.Add(grd);
private String myXAML = @" <Grid xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' Margin='30 10 30 65' VerticalAlignment='Bottom'>" +
"<Label Content='Date: 1-Feb-2013' FontFamily='Arial' FontSize='12' Foreground='#666666' HorizontalAlignment='Left'/>" +
"<Label Content='4' FontFamily='Arial' FontSize='12' Foreground='#666666' HorizontalAlignment='Center'/>" +
"<Label Content='Hello World' FontFamily='Arial' FontSize='12' Foreground='#666666' HorizontalAlignment='Right'/>" +
"</Grid>";