c# - MySql.Data via Reflection -

i use eplan scripting , want connect database. scripting engine allows load assemblies @ runtime.

my try:

assembly assmysqldata = assembly.loadfrom(@"c:\program files (x86)\mysql\mysql connector net 6.9.6\assemblies\v4.0\mysql.data.dll");          type typemysqlconnection = assmysqldata.gettype("mysql.data.mysqlclient.mysqlconnection");         type typemysqlcommand = assmysqldata.gettype("mysql.data.mysqlclient.mysqlcommand");         type typemysqldatareader = assmysqldata.gettype("mysql.data.mysqlclient.mysqldatareader");           object omysqlconnection = activator.createinstance(typemysqlconnection);          if (omysqlconnection != null)         {             methodinfo methodmysqlconnection_state = typemysqlconnection.getmethod("get_state");             methodinfo methodmysqlconnection_open = typemysqlconnection.getmethod("open");             methodinfo methodmysqlconnection_connectionstring = typemysqlconnection.getmethod("set_connectionstring");             methodinfo methodmysqlconnection_close = typemysqlconnection.getmethod("close");             methodinfo methodmysqlconnection_dispose = typemysqlconnection.getmethod("dispose");              messagebox.show(typemysqlconnection.tostring());             messagebox.show(omysqlconnection.tostring());              methodinfo methodmysqlcommand_executereader = typemysqlcommand.getmethod("executereader",new type[]{});             methodinfo methodmysqlcommand_connection = typemysqlcommand.getmethod("set_connection", new type[] {typemysqlcommand});             methodinfo methodmysqlcommand_commandtext = typemysqlcommand.getmethod("set_commandtext");             methodinfo methodmysqlcommand_dispose = typemysqlcommand.getmethod("dispose");              methodinfo methodmysqldatareader_read = typemysqldatareader.getmethod("read");             methodinfo methodmysqldatareader_hasrows = typemysqldatareader.getmethod("get_hasrows");             methodinfo methodmysqldatareader_fieldcount = typemysqldatareader.getmethod("get_fieldcount");             methodinfo methodmysqldatareader_getvalue = typemysqldatareader.getmethod("getvalue");             methodinfo methodmysqldatareader_close = typemysqldatareader.getmethod("close");             methodinfo methodmysqldatareader_dispose = typemysqldatareader.getmethod("dispose",new type[] {});               object[] arg = new object[] { (string)"server=server;port=3307;database=db;uid=me;pwd=123456;" };             methodmysqlconnection_connectionstring.invoke(omysqlconnection, arg);             methodmysqlconnection_open.invoke(omysqlconnection, null);             object mysqlstate = methodmysqlconnection_state.invoke(omysqlconnection, null);             messagebox.show(mysqlstate.tostring());              object omysqlcommand = activator.createinstance(typemysqlcommand);             if (omysqlcommand != null)             {                 object[] paramcommandconnection = new object[] { omysqlconnection }; //omysqlconnection not null                 object[] paramcommandtext = new object[] { "select * `config`" };                 methodmysqlcommand_commandtext.invoke(omysqlcommand, paramcommandtext);  //works fine                 methodmysqlcommand_connection.invoke(omysqlcommand, paramcommandconnection); // error no object                 messagebox.show("5");                 object omysqldatareader = methodmysqlcommand_executereader.invoke(omysqlcommand, null);                 messagebox.show("6");                 object retrows = methodmysqldatareader_hasrows.invoke(omysqldatareader, null);                 messagebox.show("7");                 messagebox.show(retrows.tostring());                 messagebox.show("8");             }          } 

i error on methodmysqlcommand_connection.invoke (omysqlcommand, paramcommandconnection); no instance of object. error? omysqlconnection not null - , connection state says open.

the solution

omg: i've read source (and line) many, many .. many times - can't see error :( !

typemysqlcommand.getmethod("set_connection", new type[] {typemysqlcommand}); 

change to

typemysqlcommand.getmethod("set_connection", new type[] {typemysqlconnection}); 

and works fine!

regrads raiserle