WPF中任意Object的XAML代碼格式化輸出

有時候,我們需要將WPF中的控制項自身的XAML代碼輸出成文本,那麼,我們可以使用System.Windows.Markup.XamlWriter.Save()方法來完成此任務。關於XamlWriter.Save()的樣本，我曾經在“在WPF中，如何得到任何Object對象的XAML代碼？”（http://blog.csdn.net/johnsuna/archive/2007/11/23/1899875.aspx）Blog中有所介紹，此處不再贅述。

使用上述方法時，我們發現，輸出的XAML代碼並不“標準”，不是格式化的XML代碼，我們看這樣的代碼時，會有一種頭暈的感覺。那麼，怎樣輸出成已格式化過的XAML代碼呢？

答案是藉助System.Xml.XmlWriter及對System.Xml.XmlWriterSettings設定來解決。

代碼：
以下程式碼範例示範在txtBoxXamlCode文字框中顯示名為“canvasContent”的Canvas控制項的自身XAML代碼：

// Line.xaml中的部分關鍵代碼：
<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);
            }
        }

// 輸出顯示未格式化的XAML代碼
        private void btnViewXaml_Click(object sender, RoutedEventArgs e)
        {
            txtBoxXamlCode.Text = XamlWriter.Save(canvasContent);
        }

// 輸出顯示已格式化過的XAML代碼
        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;
        }
    }
}

運行：

點擊顯示文字為XamlCode的按鈕後，輸出的代碼為：

<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>

點擊Formatted Xaml的按鈕後，得到的代碼為：

<?xml version="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>

很明顯，後者可讀性強得多。