First, I'd say use string.format to make the code more readable.
ConStr = string.Format("DRIVER={MySQL ODBC 3.51 Driver};SERVER={0};PORT= 3306;DATABASE={1};UID={2};PWD={3};OPTION=3", textBox_ip.Text, textBox_database.Text, textBox_username.Text, textBox_password.Text);
Obviously, you need to make sure the the address and port, etc. are correct.
You can also look here for examples
http://www.connectionstrings.com/[
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