【Ado.Net】SQLHelper+配置文件+参数查询

来源：互联网发布：张海迪开车知乎编辑：程序博客网时间：2024/06/05 03:06

基础代码

private void btnLogin_Click(object sender, EventArgs e){    string uid = txtUserName.Text.Trim();    string pwd = txtPwd.Text.Trim();    SqlParameter[] spa = new SqlParameter[]{        new SqlParameter("@uid",uid),        new SqlParameter("@pwd",pwd)    };    string sql = "select * from Login where UserName=@uid And Password=@pwd";    string result = SqlHelper.ExecuteDataTable(sql, spa).Rows.Count.ToString();    if (Convert.ToInt32(result)>0)    {        MessageBox.Show("登录成功！");    }    else    {        MessageBox.Show("登录失败！");    }}

SQLHelper

class SqlHelper{    //wf项目中，请添加对System.Configuration的引用    //1.对配置文件connectionStrings节进行读取    static string connstr = System.Configuration.ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;    /// <summary>    /// 查询数据库返回一张表    /// </summary>    /// <param name="sql">查询字符串</param>    /// <param name="parameters">查询所需要的参数</param>    /// <returns>返回查询的结果的第一个结果集的表</returns>    public static DataTable ExecuteDataTable(string sql, params SqlParameter[] parameters)    {        //创建一个临时的数据集，在内存里        DataSet ds = new DataSet();        //创建一个适配器对象        SqlDataAdapter adapter = new SqlDataAdapter(sql, connstr);        //给适配器对象的查询命令对象添加参数        adapter.SelectCommand.Parameters.AddRange(parameters);        try        {            //填充数据集            adapter.Fill(ds);            return ds.Tables[0];        }        catch (Exception) //如果捕捉错误就返回null        {            return null;        }    }    /// <summary>    /// 数据库的增删改语句    /// </summary>    /// <param name="sql">sql语句</param>    /// <param name="parameters">参数</param>    /// <returns></returns>    public static int ExecuteNonQuery(string sql, params SqlParameter[] parameters)    {        using (SqlConnection conn = new SqlConnection(connstr))        {            using (SqlCommand cmd = new SqlCommand(sql, conn))            {                cmd.Parameters.AddRange(parameters);                conn.Open();                return cmd.ExecuteNonQuery();            }        }    }    /// <summary>    /// 查询返回单个的值    /// </summary>    /// <param name="sql">sql语句</param>    /// <param name="parameters">参数</param>    /// <returns>首行首列的值</returns>    public static object ExecuteScalar(string sql, params SqlParameter[] parameters)    {        using (SqlConnection conn = new SqlConnection(connstr))        {            using (SqlCommand cmd = new SqlCommand(sql, conn))            {                cmd.Parameters.AddRange(parameters);                conn.Open();                return cmd.ExecuteScalar();            }        }    }}

配置文件

<configuration>  <connectionStrings>    <add name="connStr" connectionString="server=.;database=Test;uid=sa;pwd=jujianfei"/>  </connectionStrings></configuration>

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