C#无法连接 *.DB文件...求大神指点

Question

string ConnectionString = @" Driver={Microsoft Paradox Driver (*.db )};DriverID=538;Fil=Paradox 5.X;DefaultDir=" + str + ";Dbq=" + str + ";CollatingSequence=ASCII;";

string ConnectionString = @"Provider=MSDASQL;Persist Security Info=False;Mode=Read;Extended Properties='DSN=Paradox;DBQ=" + str + ";DefaultDir=" + str + ";DriverId=538;FIL=Paradox 7.X;MaxBufferSize=2048;PageTimeout=600;';Initial Catalog=" + str + ";";

string ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + str + ";Extended Properties=Paradox 5.x;";

这些链接字符串我都试过，都没用。
不然就是报“外部表不是预期的格式”这个错误，就是报“找不到指定驱动”

我都快疯了...求大神指点..