SqlHelper封装类

public static class SqlHelper
{
    //连接字符串
    private static readonly string connStr = ConfigurationManager.ConnectionStrings["mssql"].ConnectionString;


    //1.执行增、删、改的方法：ExecuteNonQuery
    public static int ExecuteNonQuery(string sql, params SqlParameter[] pms)
    {
        using (SqlConnection con = new SqlConnection(connStr))
        {
            using (SqlCommand cmd = new SqlCommand(sql, con))
            {
                if (pms != null)
                {
                    cmd.Parameters.AddRange(pms);
                }
                con.Open();
                return cmd.ExecuteNonQuery();
            }
        }
    }

    //2.封装一个执行返回单个对象的方法：ExecuteScalar()
    public static object ExecuteScalar(string sql, params SqlParameter[] pms)
    {
        using (SqlConnection con = new SqlConnection(connStr))
        {
            using (SqlCommand cmd = new SqlCommand(sql, con))
            {
                if (pms != null)
                {
                    cmd.Parameters.AddRange(pms);
                }
                con.Open();
                return cmd.ExecuteScalar();
            }
        }
    }


    //3.执行查询多行多列的数据的方法：ExecuteReader
    public static SqlDataReader ExecuteReader(string sql, params SqlParameter[] pms)
    {
        SqlConnection con = new SqlConnection(connStr);
        using (SqlCommand cmd = new SqlCommand(sql, con))
        {
            if (pms != null)
            {
                cmd.Parameters.AddRange(pms);
            }
            try
            {
                con.Open();
                return cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
            catch (Exception)
            {
                con.Close();
                con.Dispose();
                throw;
            }
        }
    }


    //4.执行返回DataTable的方法
    public static DataTable ExecuteDataTable(string sql, params SqlParameter[] pms)
    {
        DataTable dt = new DataTable();
        using (SqlDataAdapter adapter = new SqlDataAdapter(sql, connStr))
        {
            if (pms != null)
            {
                adapter.SelectCommand.Parameters.AddRange(pms);
            }
            adapter.Fill(dt);
        }
        return dt;
    }
}