Silverlight TextBlock:将文本转换为InlineCollection

时间:2011-01-19 10:25:17

标签: silverlight binding textblock

考虑以下标记声明:

<TextBlock>
 <Run>abcdefghijklmnopqrstuvwxyz</Run>
 <LineBreak/>
 <Run>0123456789</Run>
</TextBlock>

我想将任何数据绑定到TextBlock并将此数据转换为InlineCollection。使用Data Binding执行此操作会非常优雅。另一种方法是观察我的数据源并使用Code Behind中TextBlock类的Inlines-Property。

我尝试了以下但是没有用:

<TextBlock>
 <Binding Path="MyDataSource" Converter="{StaticResource MyTextConverter}"/>
</TextBlock>

我想要做的是通过将我的TextBlock封装在ViewBox中来实现自动字体缩放,还可以在任意字母数后生成LineBreaks。

提前感谢您的帮助。 最好的问候。

4 个答案:

答案 0 :(得分:2)

这很容易成为现实...... "\r\n"在正确的位置完成工作。

答案 1 :(得分:1)

我使用this答案来解决与WPF相关的问题,以提出可以向Silverlight中的TextBlock添加简单格式的Silverlight行为。格式化是通过Xml元素完成的,这些元素的工作方式与在元素本身中格式化TextBlock的方式类似。可以使用粗体,斜体,下划线和LineBreak元素。

首先,行为定义如下:


public static class FormattedTextBlockBehavior
{
    public static string GetFormattedText(DependencyObject obj)
    {
        return (string) obj.GetValue(FormattedTextProperty);
    }

    public static void SetFormattedText(DependencyObject obj, string value)
    {
        obj.SetValue(FormattedTextProperty, value);
    }

    public static readonly DependencyProperty FormattedTextProperty =
            DependencyProperty.RegisterAttached("FormattedText",
                                                typeof (string),
                                                typeof (FormattedTextBlockBehavior),
                                                new PropertyMetadata("", FormattedTextChanged));

    private static Inline Traverse(string value)
    {
        // Get the sections/inlines
        string[] sections = SplitIntoSections(value);

        // Check for grouping
        if (sections.Length.Equals(1))
        {
            string section = sections[0];
            string token; // E.g <Bold>
            int tokenStart, tokenEnd; // Where the token/section starts and ends.

            // Check for token
            if (GetTokenInfo(section, out token, out tokenStart, out tokenEnd))
            {
                // Get the content to further examination
                string content = token.Length.Equals(tokenEnd - tokenStart)
                                 ? null
                                 : section.Substring(token.Length, section.Length - 1 - token.Length*2);

                switch (token)
                {
                    case "<Bold>":
                        var b = new Bold();
                        b.Inlines.Add(Traverse(content));
                        return b;
                    case "<Italic>":
                        var i = new Italic();
                        i.Inlines.Add(Traverse(content));
                        return i;
                    case "<Underline>":
                        var u = new Underline();
                        u.Inlines.Add(Traverse(content));
                        return u;
                    case "<LineBreak/>":
                        return new LineBreak();
                    case "<LineBreak />":
                        return new LineBreak();
                    default:
                        return new Run
                                   {
                                       Text = section
                                   };
                }
            }
            return new Run
                       {
                           Text = section
                       };
        }
        var span = new Span();

        foreach (string section in sections)
            span.Inlines.Add(Traverse(section));

        return span;
    }

    /// <summary>
    /// Examines the passed string and find the first token, where it begins and where it ends.
    /// </summary>
    /// <param name="value">The string to examine.</param>
    /// <param name="token">The found token.</param>
    /// <param name="startIndex">Where the token begins.</param>
    /// <param name="endIndex">Where the end-token ends.</param>
    /// <returns>True if a token was found.</returns>
    private static bool GetTokenInfo(string value, out string token, out int startIndex, out int endIndex)
    {
        token = null;
        endIndex = -1;
        startIndex = value.IndexOf("<");
        int startTokenEndIndex = value.IndexOf(">");

        // No token here
        if (startIndex < 0)
            return false;

        // No token here
        if (startTokenEndIndex < 0)
            return false;

        token = value.Substring(startIndex, startTokenEndIndex - startIndex + 1);

        // Check for closed token. E.g. <LineBreak/>
        if (token.EndsWith("/>"))
        {
            endIndex = startIndex + token.Length;
            return true;
        }

        string endToken = token.Insert(1, "/");

        // Detect nesting;
        int nesting = 0;
        int pos = 0;
        do
        {
            int tempStartTokenIndex = value.IndexOf(token, pos);
            int tempEndTokenIndex = value.IndexOf(endToken, pos);

            if (tempStartTokenIndex >= 0 && tempStartTokenIndex < tempEndTokenIndex)
            {
                nesting++;
                pos = tempStartTokenIndex + token.Length;
            }
            else if (tempEndTokenIndex >= 0 && nesting > 0)
            {
                nesting--;
                pos = tempEndTokenIndex + endToken.Length;
            }
            else // Invalid tokenized string
               return false;

        } while (nesting > 0);

        endIndex = pos;

        return true;
    }

    /// <summary>
    /// Splits the string into sections of tokens and regular text.
    /// </summary>
    /// <param name="value">The string to split.</param>
    /// <returns>An array with the sections.</returns>
    private static string[] SplitIntoSections(string value)
    {
        var sections = new List<string>();
        while (!string.IsNullOrEmpty(value))
        {
            string token;
            int tokenStartIndex, tokenEndIndex;
            // Check if this is a token section
            if (GetTokenInfo(value, out token, out tokenStartIndex, out tokenEndIndex))
            {
                // Add pretext if the token isn't from the start
                if (tokenStartIndex > 0)
                    sections.Add(value.Substring(0, tokenStartIndex));

                sections.Add(value.Substring(tokenStartIndex, tokenEndIndex - tokenStartIndex));
                value = value.Substring(tokenEndIndex); // Trim away
            }
            else
            {
                // No tokens, just add the text
                sections.Add(value);
                value = null;
            }
        }

        return sections.ToArray();
    }

    private static void FormattedTextChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        var value = e.NewValue as string;

        var textBlock = sender as TextBlock;

        if (textBlock != null)
            textBlock.Inlines.Add(Traverse(value));
    }

然后,从xaml本身,行为可以如下引用:

  xmlns:Helpers="clr-namespace:Namespace.Helpers" 

  <TextBlock Grid.Row="0" Margin="10,10,10,10" TextWrapping="Wrap" FontSize="14" Helpers:FormattedTextBlockBehavior.FormattedText="{Binding ViewModel.Text}" />

答案 2 :(得分:0)

我猜你只需要将转换器分配给TextBlock的TextProperty。 然后您的转换器会添加\r\n以在需要时添加换行符。

答案 3 :(得分:0)

我想我通过对TextBlock进行子类化以使InlineCollection可绑定并在xaml标记的String和InlineCollection(或Inlines的通用列表)之间编写转换器来回答这个问题。]

Details here on the Stack

正如infografnet所指出的,TextBlock类的Silverlight版本为sealed,这使我的WPF子分类建议无效。