C#连接SqlServer数据库

using System.Data;
using System.Data.SqlClient;

namespace SQLServer
{
    public class SQLServerDataBase
    {
        string _connString = "server=127.0.0.1;database=User;uid=sa;pwd=123";

        public SQLServerDataBase(string connStr)
        {
            _connString = connStr;
        }

        public bool OpenDataBase()
        {
            try
            {
                //创建数据库连接对象
                using (SqlConnection sqlConn = new SqlConnection(_connString))
                {
                    //打开连接
                    sqlConn.Open();
                    sqlConn.Close();
                    return true;
                }
            }
            catch
            {
                return false;
            }
        }

        ///<summary>
        ///定义函数根据传入的参数，执行SQL语句获取影响的行数
        ///</summary>
        public bool ExecuteNonQuery(string sql, out int iResult)
        {
            iResult = 0;
            //创建连接数据库对象
            using (SqlConnection sqlConn = new SqlConnection(_connString))
            {
                //打开连接
                sqlConn.Open();
                //创建执行SQL语句对象
                using (SqlCommand sqlCmd = new SqlCommand(sql, sqlConn))
                {
                    iResult = sqlCmd.ExecuteNonQuery();
                    sqlConn.Close();
                    sqlCmd.Dispose();
                    return true;
                }
            }
        }

        ///<summary>
        ///定义函数根据传入的参数，执行SQL语句获取数据集DataSet对象
        ///</summary>
        public bool ExecuteNonDataSet(string sql, out DataSet dataSet)
        {
            dataSet = null;
            //创建连接数据库对象
            using (SqlConnection sqlConn = new SqlConnection(_connString))
            {
                //创建执行SQL语句对象
                using (SqlDataAdapter sqlData = new SqlDataAdapter(sql, sqlConn))
                {
                    //打开连接
                    sqlConn.Open();
                    dataSet = new DataSet();
                    sqlData.Fill(dataSet, "ds");
                    sqlConn.Close();
                    sqlData.Dispose();
                    return true;
                }
            }

        }

    }
}