WPF中任意Object的XAML代码格式化输出

有时候,我们需要将WPF中的控件自身的XAML代码输出成文本,那么,我们可以使用System.Windows.Markup.XamlWriter.Save()方法来完成此任务。关于XamlWriter.Save()的示例，我曾经在“在WPF中，如何得到任何Object对象的XAML代码？”Blog中有所介绍，此处不再赘述。

使用上述方法时，我们发现，输出的XAML代码并不“标准”，不是格式化的XML代码，我们看这样的代码时，会有一种头晕的感觉。那么，怎样输出成已格式化过的XAML代码呢？

答案是借助System.Xml.XmlWriter及对System.Xml.XmlWriterSettings设置来解决。

代码：
以下代码示例演示在txtBoxXamlCode文本框中显示名为“canvasContent”的Canvas控件的自身XAML代码：

// Line.xaml中的部分关键代码：
<Canvas Width="630" Height="400" Name="canvasContent">
// Line.xaml.cs：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using Shapes = System.Windows.Shapes;
using System.Windows.Markup;
using System.Xml;namespace BrawDraw.Com.Book.WPF.Demo.Lines
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class LineDemo : Window
    {
        public LineDemo()
        {
            InitializeComponent();
            InitCanvasChildren();
        }        private void InitCanvasChildren()
        {
            double angle = 120;
            double centerX = 200;
            double centerY = 200;
            double strokeThickness = 10;            for (int i = 0; i < 360; i += (int)angle)
            {
                Shapes.Line lineRotate = new System.Windows.Shapes.Line();
                lineRotate.Stroke = new SolidColorBrush(Colors.Black);
                lineRotate.X1 = 0;
                lineRotate.Y1 = centerY;
                lineRotate.X2 = centerX;
                lineRotate.Y2 = centerY;
                lineRotate.StrokeDashArray = new DoubleCollection(new double[] { 0, 3 });
                lineRotate.StrokeThickness = strokeThickness;
                lineRotate.StrokeDashCap = PenLineCap.Round;
                lineRotate.StrokeStartLineCap = PenLineCap.Round;
                lineRotate.StrokeEndLineCap = PenLineCap.Round;
                RotateTransform rt = new RotateTransform(i, centerX, centerY);
                lineRotate.RenderTransform = rt;
                canvasContent.Children.Add(lineRotate);
            }
        }// 输出显示未格式化的XAML代码
        private void btnViewXaml_Click(object sender, RoutedEventArgs e)
        {
            txtBoxXamlCode.Text = XamlWriter.Save(canvasContent);
        }

// 输出显示已格式化过的XAML代码
        private void btnViewFormattedXaml_Click(object sender, RoutedEventArgs e)
        {
            XmlWriterSettings settings = new XmlWriterSettings();
            settings.Indent = true;
            settings.IndentChars = new string(' ', 4);
            settings.NewLineOnAttributes = true;
            StringBuilder sb = new StringBuilder();
            XmlWriter xmlWriter = XmlWriter.Create(sb, settings);
            XamlWriter.Save(canvasContent, xmlWriter);
            txtBoxXamlCode.Text = sb.ToString();
            xmlWriter.Close();
            sb = null;
        }
    }
}

运行效果图：

点击显示文字为XamlCode的按钮后，输出的代码为：

<Canvas Name="canvasContent" Width="630" Height="400" xmlns="​​http://schemas.microsoft.com/winfx/2006/xaml/presentation"><Line​​ X1="0" Y1="200" X2="200" Y2="200" Stroke="#FF000000" StrokeThickness="10" StrokeStartLineCap="Round" StrokeEndLineCap="Round" StrokeDashCap="Round" StrokeDashArray="0 3"><Line.RenderTransform><RotateTransform Angle="0" CenterX="200" CenterY="200" /></Line.RenderTransform></Line><Line X1="0" Y1="200" X2="200" Y2="200" Stroke="#FF000000" StrokeThickness="10" StrokeStartLineCap="Round" StrokeEndLineCap="Round" StrokeDashCap="Round" StrokeDashArray="0 3"><Line.RenderTransform><RotateTransform Angle="120" CenterX="200" CenterY="200" /></Line.RenderTransform></Line><Line X1="0" Y1="200" X2="200" Y2="200" Stroke="#FF000000" StrokeThickness="10" StrokeStartLineCap="Round" StrokeEndLineCap="Round" StrokeDashCap="Round" StrokeDashArray="0 3"><Line.RenderTransform><RotateTransform Angle="240" CenterX="200" CenterY="200" /></Line.RenderTransform></Line></Canvas>

点击Formatted Xaml的按钮后，得到的代码为：

<?xml versinotallow="1.0" encoding="utf-16"?>
<Canvas
    Name="canvasContent"
    Width="630"
    Height="400" xmlns="​​http://schemas.microsoft.com/winfx/2006/xaml/presentation​​">
    <Line
        X1="0"
        Y1="200"
        X2="200"
        Y2="200"
        Stroke="#FF000000"
        StrokeThickness="10"
        StrokeStartLineCap="Round"
        StrokeEndLineCap="Round"
        StrokeDashCap="Round"
        StrokeDashArray="0 3">
        <Line.RenderTransform>
            <RotateTransform
                Angle="0"
                CenterX="200"
                CenterY="200" />
        </Line.RenderTransform>
    </Line>
    <Line
        X1="0"
        Y1="200"
        X2="200"
        Y2="200"
        Stroke="#FF000000"
        StrokeThickness="10"
        StrokeStartLineCap="Round"
        StrokeEndLineCap="Round"
        StrokeDashCap="Round"
        StrokeDashArray="0 3">
        <Line.RenderTransform>
            <RotateTransform
                Angle="120"
                CenterX="200"
                CenterY="200" />
        </Line.RenderTransform>
    </Line>
    <Line
        X1="0"
        Y1="200"
        X2="200"
        Y2="200"
        Stroke="#FF000000"
        StrokeThickness="10"
        StrokeStartLineCap="Round"
        StrokeEndLineCap="Round"
        StrokeDashCap="Round"
        StrokeDashArray="0 3">
        <Line.RenderTransform>
            <RotateTransform
                Angle="240"
                CenterX="200"
                CenterY="200" />
        </Line.RenderTransform>
    </Line>
</Canvas>

很明显，后者可读性强得多。