输入一个非数字值就会出现一个错误通知。
Entering a non-numeric value should cause an error notification.
一个特殊值，此值指示算术表达式返回了非数字值。
A special value that indicates an arithmetic expression returned a value that was not a number.
只对RGB颜色、位掩码、及其它非数字值使用uint。
Use uint only for RGB colors, bit masks, and other non-numeric values.
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