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//连接mysql数据库
MySqlConnectionStringBuilder sb = new MySqlConnectionStringBuilder();
sb.Server = "127.0.0.1";
sb.Port = 3306;
sb.Database = "tracesystem";
sb.UserID = "root";
sb.Password = "123456";
sb.CharacterSet = "gb2312";
MySqlConnection con = new MySqlConnection(sb.ConnectionString);//实例化连接
con.Open();
{
String query = "select * from user where username='" + name + "'";//向数据库服务器发送指令
// String query = "select * from user";//向数据库服务器发送指令
MySqlCommand cmd = new MySqlCommand(query, con);
//执行结果赋值到dr,dr为只读
MySqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
string username = dr["name"].ToString();
if (textBox1.Text == username)
{
MessageBox.Show("该用户已存在,请重新注册!");
}
string username = dr["phone"].ToString();
else if (textBox1.Text == username)
{
MessageBox.Show("该手机号已存在,请重新注册!");
}
}