c# - 如何确定字符串中是否包含此 SpriteFont 无法解析的字符？

Question

当我绘制 SpriteFont 中不支持的字符时，出现异常。 TextboxString 是使用软键盘输入的字符串。玩家可以在我的 iOS/Android 应用程序中使用软键盘输入他的显示名称、密码和电子邮件地址。

    private async Task<string> ShowKeyboard(string messageboxtitle, string messageboxdescription, string text, bool ispassword)
    {
        string TextboxString = "";
        await Task.Run(async () =>
        {           
            var result = await KeyboardInput.Show(messageboxtitle, messageboxdescription, text, ispassword);
            if (null != result)
            {
                TextboxString = result;
            }
        });

        KeyboardActiv = false;

        return TextboxString;
    }

例如，如果 TextboxString = "Player_磨"; 那么我会得到一个异常，因为我不支持中文字符。我只想支持英语、西类牙语、意大利语、法语、德语和葡萄牙语字符。

spriteBatch.DrawString(Font, TextboxString, new Vector2(100, 500), Microsoft.Xna.Framework.Color.Black);

System.ArgumentException has been thrown

Text contains characters that cannot be resolved by this SpriteFont. Parameter name: text

如何查明玩家是否输入了我的 spriteFont 不支持的字符？

如果玩家输入了不支持的字符，我想在我的应用程序中显示一条消息。

我的 spriteFont 文件:

<?xml version="1.0" encoding="utf-8"?>
<!--
This file contains an xml description of a font, and will be read by the XNA
Framework Content Pipeline. Follow the comments to customize the appearance
of the font in your game, and to change the characters which are available to draw
with.
-->
<XnaContent xmlns:Graphics="Microsoft.Xna.Framework.Content.Pipeline.Graphics">
  <Asset Type="Graphics:FontDescription">

    <!--
    Modify this string to change the font that will be imported.
    -->
    <FontName>Arial</FontName>

    <!--
    Size is a float value, measured in points. Modify this value to change
    the size of the font.
    -->
    <Size>28</Size>

    <!--
    Spacing is a float value, measured in pixels. Modify this value to change
    the amount of spacing in between characters.
    -->
    <Spacing>0</Spacing>

    <!--
    UseKerning controls the layout of the font. If this value is true, kerning information
    will be used when placing characters.
    -->
    <UseKerning>true</UseKerning>

    <!--
    Style controls the style of the font. Valid entries are "Regular", "Bold", "Italic",
    and "Bold, Italic", and are case sensitive.
    -->
    <Style>Regular</Style>

    <!--
    If you uncomment this line, the default character will be substituted if you draw
    or measure text that contains characters which were not included in the font.
    -->
    <!-- <DefaultCharacter>?</DefaultCharacter> -->

    <!--
    CharacterRegions control what letters are available in the font. Every
    character from Start to End will be built and made available for drawing. The
    default range is from 32, (ASCII space), to 126, ('~'), covering the basic Latin
    character set. The characters are ordered according to the Unicode standard.
    See the documentation for more information.
    -->
    <CharacterRegions>
      <CharacterRegion>
      <Start>&#32;</Start>
      <End>&#512;</End>
      </CharacterRegion>
      <CharacterRegion>
      <!-- Apostrophe 8217 -->
      <Start>&#8216;</Start>
      <End>&#8222;</End>
      </CharacterRegion>
      <CharacterRegion>
      <!-- Currency symbols -->
      <Start>&#8352;</Start>
      <End>&#8378;</End>
      </CharacterRegion>
    </CharacterRegions>
  </Asset>
</XnaContent>

Answer 1

这里有两个选择:

1) 使用 SpriteFont.Characters.Contains 检查输入的字符是否在给定的 spriteFont 文件中表示。

2) 使用正则表达式。用于电子邮件验证和使用(例如)某些字符和数字的正确正则表达式示例很容易找到。

编辑: 无论如何，建议进行某种电子邮件检查，以确保用户坚持使用“local-part@domain-part”