The callback or callback parameter is invalid.

Latest updateProgramThe following error message always appears:

Follow the prompts to set enableeventvalidation = "false" in the page command.

The search results can be interpreted as follows:

First, form nesting. One page can only have one form. Check carefully.CodeYou can solve this problem.
Second, Ajax is used in the drop-down menu, which is common in the provincial/municipal linkage menu. It may be because the initial item value of the drop-down menu is assigned to the ASPX page. This error is prompted when the event is returned, delete the initial item value from the drop-down menu and add the item to the binding event.

If Ajax is used in 2nd cases, change the server dropdownlist to select runat = server to solve the problem.

 

I really don't want to modify it every time I update it. I whispered that a local test didn't show up. record the results of the csdn query.

Add enableeventvalidation = "false" to the page"

The cause of this error is probably because the verification fails because the server-side control, for example, the internal value of the dropdownlist container, is changed. You can set this error to 2.0.

The result of the msdn query is:

The enableeventvalidation attribute indicates whether event verification should be performed. This attribute is added in. NET Framework 2.0.

The basic control checks this property to determine whether the event should be verified. The derived control does not inherit this basic control property, so event verification is not performed by default. By adding the enableeventvalidation attribute to the derived control and setting it to true, you can still instruct ASP. NET to perform event verification on the derived control.

Note:
This event verification mechanism can eliminate the risk of unauthorized sending back requests and callbacks. It instructs ASP. NET to verify only the specific events that are triggered on the control during the sending back request or callback. With this model, the control registers its events during rendering, and then verifies these events during sending back or callback. By default, all event-driven controls in ASP. NET now use this function:

If the enableeventvalidation attribute is not defined, the custom control will participate in event verification only when validateevent is explicitly called. If event registration and verification are processed and validateevent is called, you do not need to define this property on the control. If this attribute is defined but event verification is not registered, an exception "invalid sending back or callback Parameters" will occur during the runtime ".

I asked the webmaster that the ASP. NET version on the server was 2.0, but the local version was 1.1. Ah, I finally found the root cause of the problem, O (problem _ problem) O ~

 

This problem has been extended, and it is very depressing.