C#连接SQLServer数据库

usingSystem;
usingSystem.Collections.Generic;
usingSystem.Linq;
usingSystem.Text;
usingSystem.Threading.Tasks;

usingSystem.Data;
usingSystem.Data.Sql;
usingSystem.Data.SqlClient;
//这个是连接数据库用的类
namespaceSQLConnectWindows
{
    classsqlhelper
    {
        //数据库名称
        public  string sourceName = "UQVYNFZSKG81DQB";
        //用户名称
        public  string userName = "sa";
        //用户密码
        public  string pwd = "123456";
        //连接的数据库名称
        public  string database = "zd_tcTwo";
        //连接数据库
SqlConnection conn;
        //执行操作
        DataSet dataSet = newDataSet();
        
        public DataSet MySQLConnect(stringsql)
        {
            //连接数据库
            string connstr = "data source=" + sourceName + ";user=" + userName + ";pwd=" + pwd + ";database=" +database;
            conn = newSqlConnection(connstr);

            try{
                //打开数据库连接
conn.Open();

                //执行sql命令
                SqlCommand cmd = newSqlCommand(sql, conn);


                //适配命令通道
                SqlDataAdapter adapter = newSqlDataAdapter(cmd);
                
                //命令执行
adapter.Fill(dataSet);

                //清除参数
cmd.Parameters.Clear();
                
            }
            catch(Exception e)
            {
                Console.Write(e.Message);
            }
            finally{
                //关闭数据库连接
conn.Close();
            }
            returndataSet;
        }}
}

//可以存在于其他类中
private void button1_Click(objectsender, EventArgs e)
        {
            try{
                string cmd = "INSERT INTO [dbo].[userInfo]([uid],[uname],[umid])VALUES('" + 1 + "','" + 1 + "','" + 1 + "')";
                sqlhelper.MySQLConnect(cmd);
            }
            catch(DataException data) {
                Console.Write(data.Message);
            }
        }