app.config连接数据库的配置

app.config连接数据库的配置 
【转载新浪博客】

<?xml version="1.0" encoding="utf-8" ?>

<configuration>

  <connectionStrings>

    <add name="connString" connectionString="Data Source=.;database=Northwind;User ID=sa;Password="/>

  </connectionStrings>

</configuration>

在后台读取：

     SqlConnection conn = new SqlConnection();

            conn.ConnectionString = ConfigurationManager.ConnectionStrings["connString"].ConnectionString;

            conn.Open();

            string sql = "select * from Orders";

            SqlCommand cmd = new SqlCommand(sql, conn);

            SqlDataAdapter da = new SqlDataAdapter();

            da.SelectCommand = cmd;

            DataSet ds = new DataSet();

            da.Fill(ds);

            this.dataGridView1.DataSource = ds.Tables[0];

            conn.Close();

配置节:

1、这样配置的话

<connectionStrings>

    <add name="connString" connectionString="Data Source=.;Initial Catalog=Test;User ID=sa;Password=sasa"/>

</connectionStrings>

这样：

conn.ConnectionString = ConfigurationManager.ConnectionStrings["connString"].ConnectionString;

2、这样配置的话

<appSettings>

    <add key="connString" value="Data Source=.;Initial Catalog=Test;User ID=sa;Password=sasa;" />

</appSettings>

这样：

conn.ConnectionString = ConfigurationManager.AppSettings["connString"];