原文:

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=" 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 version="1.0" encoding="utf-16"?>

<Canvas

    Name="canvasContent"

    Width="630"

    Height="400" xmlns="">

    <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。