SqlHelper

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using System;using System.Collections.Generic;using System.Configuration;using System.Data;using System.Data.SqlClient;using System.Linq;using System.Text;using System.Threading.Tasks;namespace ExecuteReader{    class SqlHelper    {        private static string connStr = ConfigurationManager.ConnectionStrings["adConnStr"].ConnectionString;        //封装方法原则：把不变的放到方法里，把变化的放到参数中        //public static int  ExecuteNonQuery(string sql)        //{        //    using (SqlConnection conn = new SqlConnection (connStr))        //    {        //        conn.Open();        //        using (SqlCommand cmd = conn.CreateCommand ())        //        {        //            cmd.CommandText = sql;        //            return cmd.ExecuteNonQuery();        //        }        //    }        //}        //public static object ExecuteScalary(string sql)        //{        //    using (SqlConnection conn = new SqlConnection (connStr))        //    {        //        conn.Open();        //        using (SqlCommand cmd = conn.CreateCommand ())        //        {        //            cmd.CommandText = sql;        //            return cmd.ExecuteScalar();        //        }        //    }        //}        ////只用来执行查询结果比较少的sql        //public static DataTable ExecuteDataTables(string sql)        //{        //    using (SqlConnection conn = new SqlConnection(connStr))        //    {        //        conn.Open();        //        using (SqlCommand cmd = conn.CreateCommand())        //        {        //            cmd.CommandText = sql;        //            SqlDataAdapter adapter = new SqlDataAdapter(cmd);        //            DataSet dataset = new DataSet();        //            adapter.Fill(dataset);        //            return dataset.Tables[0];        //        }        //    }        //}      //  封装方法原则：把不变的放到方法里，把变化的放到参数中        public static int  ExecuteNonQuery(string sql ,SqlParameter [] parameters )        {            using (SqlConnection conn = new SqlConnection (connStr))            {                conn.Open();                using (SqlCommand cmd = conn.CreateCommand ())                {                    cmd.CommandText = sql;                    cmd.Parameters.AddRange(parameters);                    return cmd.ExecuteNonQuery();                }            }        }        public static object ExecuteScalary(string sql ,params SqlParameter [] parameters)        {            using (SqlConnection conn = new SqlConnection(connStr))            {                conn.Open();                using (SqlCommand cmd = conn.CreateCommand())                {                    cmd.CommandText = sql;                    cmd.Parameters.AddRange(parameters);                    return cmd.ExecuteScalar();                }            }        }        //只用来执行查询结果比较少的sql        public static DataTable ExecuteDataTables(string sql , params  SqlParameter [] parameters)        {            using (SqlConnection conn = new SqlConnection(connStr))            {                conn.Open();                using (SqlCommand cmd = conn.CreateCommand())                {                    cmd.CommandText = sql;                    cmd.Parameters.AddRange(parameters);                    SqlDataAdapter adapter = new SqlDataAdapter(cmd);                    DataSet dataset = new DataSet();                    adapter.Fill(dataset);                    return dataset.Tables[0];                }            }        }    }}

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        private void Button_Click_3(object sender, RoutedEventArgs e)        {         //   SqlHelper.ExecuteNonQuery("insert into T_Student(Name ,Age) values('方法',323)");            DataTable table = SqlHelper.ExecuteDataTables("select * from T_Student where Age = @Age  or Name = @Name "                , new SqlParameter("@Age", 23), new SqlParameter("@Name", "方法"));            foreach (DataRow row in table.Rows)            {                string name = (string)row["Name"];                MessageBox.Show(name);            }        }        private void Button_Click_4(object sender, RoutedEventArgs e)        {        //    DataTable table = SqlHelper.ExecuteDataTables("select * from T_Student where age >50");        //    foreach(DataRow row in table.Rows)        //    {        //        string name = (string)row["Name"];        //        MessageBox.Show(name);        //    }            DataTable table = SqlHelper.ExecuteDataTables("select * from T_Student where age >@age"                 ,new SqlParameter[] {new SqlParameter("@age",50)});            foreach (DataRow row in table.Rows)            {                string name = (string)row["Name"];                MessageBox.Show(name);            }        }

配置文件

<?xml version="1.0" encoding="utf-8" ?><configuration>    <startup>         <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />    </startup>  <connectionStrings>    <add  name="adConnStr" connectionString ="Data Source=. ; Initial Catalog=MyTest;User ID = sa; Password =****** "/>  </connectionStrings></configuration>

</pre><pre name="code" class="csharp">

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