The type or namespace name 'mysql' could not be found. Net error when connecting to MySQL

The type or namespace name 'mysql' could not be found.
------------- If the IDE is vs.net then you copy the DLL into C: \ WINDOWS \ Microsoft. net \ framework \ v1.1.4322 or the newest version of. net Framework you have in the framework folder, cocould be v1.0.3705, just depends what version you have in there. copy the DLL in there and add the reference in the. net ide by going to project, add reference, then select File
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This error occurs during build solution because I only put this DLL under bin and added the DLL to add reference. However, this is not enough. I should put this DLL in C: \ windows \ Microsoft. net \ framework \ v2.0.50727
Under this folder!
In this way, MySQL. Data is displayed under the. NET tab when you add reference.
------------- In sharpdevelop (the ide I know) You need to reference the MySQL GAC entry (right click on reference in the project Tree View, click Add, then find the MySQL DLL in the GAC ).
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This dll is downloaded from the Internet, with a size of kb.