C# 如何确定字符串是否包含此SpriteFont无法解析的字符？

当我绘制在我的

SpriteFont

中不受支持的字符时，会出现异常

TextboxString

是用软键盘输入的字符串。玩家可以在my

iOS/Android

应用程序中使用软键盘输入其显示名称、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;
    }

已引发System.ArgumentException

文本包含以下字符： 无法通过此SpriteFont解决。参数名称：text

如何确定玩家输入的角色在我的spriteFont中不受支持

如果玩家输入了不受支持的角色，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>

Arial
28
0
真的
有规律的
 
Ȁ
‘
„
₠
₺

这里有两个选项：

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

(二) 使用正则表达式。电子邮件验证和使用（例如）某些字符和数字的适当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“本地邮件”-part@domain-部分'

<?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>