“Operation is not valid due to the current state of the object.”

　　将Repeater单页显示的2000条数据一次性提交的时候出现这个错误：

Operation is not valid due to the current state of the object.

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.InvalidOperationException: Operation is not valid due to the current state of the object.

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.

　　这是因为提交表单form时的fields集合大小限制，参考：

http://*.com/questions/8684049/asp-net-ms11-100-how-can-i-change-the-limit-on-the-maximum-number-of-posted-for

https://technet.microsoft.com/library/security/ms11-100

　　解决办法就是修改config文件：

<appSettings>
    <add key="aspnet:MaxHttpCollectionKeys" value="5000" />
</appSettings>