如何在XNA中使用带有不完整字符集的基于纹理的spritefonts？

Question

我使用SpriteFont 2.0.1软件创建了一个基于纹理的字体。如果我使用默认的字符范围（数字，大写/非大写字母等），它的效果很好。但是，现在我想创建一个仅包含0-9和A-Z（仅大写字母）的spritefont。我导出的纹理可以在：

找到

https://dl.dropboxusercontent.com/u/55996726/LuckiestGuy.png

XNA中使用的* .spritefont文件是：

<?xml version="1.0" encoding="utf-8"?>

<XnaContent xmlns:Graphics="Microsoft.Xna.Framework.Content.Pipeline.Graphics">
  <Asset Type="Graphics:FontDescription">

  <!--
    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>

<fontMetrics file="LuckiestGuy.png">

  <character key="48">
    <x>1</x>
    <y>1</y>
    <width>53</width>
    <height>67</height>
  </character>
  <character key="49">
    <x>55</x>
    <y>1</y>
    <width>39</width>
    <height>67</height>
  </character>
  <character key="50">
    <x>95</x>
    <y>1</y>
    <width>46</width>
    <height>67</height>
  </character>
  <character key="51">
    <x>142</x>
    <y>1</y>
    <width>47</width>
    <height>67</height>
  </character>
  <character key="52">
    <x>190</x>
    <y>1</y>
    <width>48</width>
    <height>67</height>
  </character>
  <character key="53">
    <x>239</x>
    <y>1</y>
    <width>48</width>
    <height>67</height>
  </character>
  <character key="54">
    <x>288</x>
    <y>1</y>
    <width>49</width>
    <height>67</height>
  </character>
  <character key="55">
    <x>338</x>
    <y>1</y>
    <width>46</width>
    <height>67</height>
  </character>
  <character key="56">
    <x>385</x>
    <y>1</y>
    <width>49</width>
    <height>67</height>
  </character>
  <character key="57">
    <x>435</x>
    <y>1</y>
    <width>49</width>
    <height>67</height>
  </character>
  <character key="65">
    <x>485</x>
    <y>1</y>
    <width>56</width>
    <height>67</height>
  </character>
  <character key="66">
    <x>542</x>
    <y>1</y>
    <width>51</width>
    <height>67</height>
  </character>
  <character key="67">
    <x>594</x>
    <y>1</y>
    <width>47</width>
    <height>67</height>
  </character>
  <character key="68">
    <x>642</x>
    <y>1</y>
    <width>50</width>
    <height>67</height>
  </character>
  <character key="69">
    <x>693</x>
    <y>1</y>
    <width>45</width>
    <height>67</height>
  </character>
  <character key="70">
    <x>739</x>
    <y>1</y>
    <width>45</width>
    <height>67</height>
  </character>
  <character key="71">
    <x>785</x>
    <y>1</y>
    <width>53</width>
    <height>67</height>
  </character>
  <character key="72">
    <x>839</x>
    <y>1</y>
    <width>52</width>
    <height>67</height>
  </character>
  <character key="73">
    <x>892</x>
    <y>1</y>
    <width>33</width>
    <height>67</height>
  </character>
  <character key="74">
    <x>926</x>
    <y>1</y>
    <width>47</width>
    <height>67</height>
  </character>
  <character key="75">
    <x>974</x>
    <y>1</y>
    <width>54</width>
    <height>67</height>
  </character>
  <character key="76">
    <x>1029</x>
    <y>1</y>
    <width>43</width>
    <height>67</height>
  </character>
  <character key="77">
    <x>1073</x>
    <y>1</y>
    <width>62</width>
    <height>67</height>
  </character>
  <character key="78">
    <x>1136</x>
    <y>1</y>
    <width>57</width>
    <height>67</height>
  </character>
  <character key="79">
    <x>1194</x>
    <y>1</y>
    <width>54</width>
    <height>67</height>
  </character>
  <character key="80">
    <x>1249</x>
    <y>1</y>
    <width>51</width>
    <height>67</height>
  </character>
  <character key="81">
    <x>1301</x>
    <y>1</y>
    <width>57</width>
    <height>67</height>
  </character>
  <character key="82">
    <x>1359</x>
    <y>1</y>
    <width>51</width>
    <height>67</height>
  </character>
  <character key="83">
    <x>1411</x>
    <y>1</y>
    <width>48</width>
    <height>67</height>
  </character>
  <character key="84">
    <x>1460</x>
    <y>1</y>
    <width>49</width>
    <height>67</height>
  </character>
  <character key="85">
    <x>1510</x>
    <y>1</y>
    <width>52</width>
    <height>67</height>
  </character>
  <character key="86">
    <x>1563</x>
    <y>1</y>
    <width>56</width>
    <height>67</height>
  </character>
  <character key="87">
    <x>1620</x>
    <y>1</y>
    <width>71</width>
    <height>67</height>
  </character>
  <character key="88">
    <x>1692</x>
    <y>1</y>
    <width>55</width>
    <height>67</height>
  </character>
  <character key="89">
    <x>1748</x>
    <y>1</y>
    <width>56</width>
    <height>67</height>
  </character>
  <character key="90">
    <x>1805</x>
    <y>1</y>
    <width>45</width>
    <height>67</height>
  </character>
</fontMetrics>
  </Asset>
</XnaContent>

然而，XNA给我一个错误，说“这个spritefont中没有字符'E'（0x0045）。”当我想渲染以'E'开头的单词时。我做错了什么？