WPF中任意Object的XAML代码格式化输出-白红宇

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：
输出格式化的XAML代码

点击显示文字为XamlCode的按钮后，输出的代码为：

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。