Invalid temp directory in chart handler configuration [c:\TempImageFiles\]

使用MSChart控件的时候有时候会碰到这样的问题：

Invalid temp directory in chart handler configuration [c:\TempImageFiles\].

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.IO.DirectoryNotFoundException: Invalid temp directory in chart handler configuration [c:\TempImageFiles\].

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:
...

调试过程中不存在，发布到IIS才报此错。
解决方法：
1，把错误提示中不存在的路径建立一个真正的文件夹，因为假如不存在，系统不会自己建。
2，在   

 <appSettings>
     <add key="ChartImageHandler" value="storage=file;timeout=20;dir=c:\TempImageFiles\;" />
 </appSettings>

这个节点，要么把dir配置成一个真实存在的路径，要么把dir这一段去掉