Cocould not load file or assembly 'System. Web. Extensions...

Debug and run Ajax. Net locally.ProgramThere is no problem at all, but once uploaded to the server, many web. config file exceptions will occur. The following are two typical exceptions: Configuration Error Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately. Parser error message: cocould not load file or assembly 'System. web. extensions, version = 1.0.61025.0, culture = neutral, publickeytoken = 31bf3856ad364e35 'or one of its dependencies. the system cannot find the specified file. ------------------------------------------------ Configuration Error Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately. Parser error message: cocould not load file or assembly 'System. web. extensions. design, version = 1.0.61025.0, culture = neutral, publickeytoken = 31bf3856ad364e35 'or one of its dependencies. the system cannot find the specified file. A: The cause of this problem is said to be Microsoft. When we released the website, we automatically generated the DLL file to the bin directory of the program. However, Ajax. Net cannot automatically add key DLL files to the bin directory. This problem is especially common when the version on the server is different from the Ajax version we used during development (for example, the local Ajax version is an old version). Therefore, we need to manually add the version. The method is simple. Find the directory for installing Ajax. Net in your development environment, which is generally similar to c: \ Program Files \ Microsoft ASP. NET \ ASP. NET 2.0 Ajax extensions \ v1.0.61025 Copy the system. Web. Extensions. dll file and System. Web. Extensions. Design. dll file to the bin directory. Of course, the file to copy depends on the exception information in your web. config file.