方法一:将 Page 指令的ValidateRequest属性值设置为false
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<%@ Page Language="C#" AutoEventWireup="true" ValidateRequest="false" CodeFile="Default.aspx.cs" Inherits="_Default" Debug="true" %>
方法二:在web.config中设置ValidateRequest属性值设置为false(默认true)
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<configuration>
<system.web>
<pages validateRequest="false" />
</system.web>
</configuration>
<system.web>
<pages validateRequest="false" />
</system.web>
</configuration>