使用C#winform中的app.config访问数据库连接字符串

Question

我似乎无法在我的c#winforms应用程序中访问app.config数据库连接字符串.

app.config代码

   <connectionStrings>
      <add name="MyDBConnectionString" providerName="System.Data.SqlClient"
            connectionString="Data Source=localhost;Initial Catalog=MySQLServerDB; Integrated Security=true" />
   </connectionStrings>  

C#代码:

SqlConnection conn = new SqlConnection();
conn.ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["MyDBConnectionString"];    

当我尝试C#代码时,我收到一条消息:
警告1'System.Configuration.ConfigurationSettings.AppSettings'已过时:'此方法已过时,已被System.Configuration取代!System.Configuration.ConfigurationManager.AppSettings'

但是,当我尝试使用时:

conn.ConnectionString = System.Configuration!System.Configuration.ConfigurationManager.AppSettings["MyDBConnectionString"];  

我收到一个错误:只有赋值,调用,递增,递减和新对象表达式才能用作语句

Answer 1

这就是你所需要的:

System.Configuration.ConfigurationManager.ConnectionStrings["MyDBConnectionString"].ConnectionString;

Answer 2

用ConfigurationManager而不是ConfigurationSettings.它有一个ConnectionStrings属性,你应该用于该connectionStrings部分中的连接字符串:

ConfigurationManager.ConnectionStrings["MyDBConnectionString"].ConnectionString;

Answer 3

您正在使用ConnectionStrings集合,而不是AppSettings.

ConfigurationManager.ConnectionStrings["MyDbConnectionString"].ConnectionString;

Answer 4

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

<appSettings>

<add key="ConnectionString" value="Data Source=MY-PC;Initial Catalog=DB2013;User ID=sa;Password=MYSQL123" />

</appSettings>

</configuration>
using System.Configuration;
using System.Data.SqlClient;

namespace OnlineDelete_W2013
{
public partial class CommodityEdit : Form
{
   SqlConnection MyConnection = new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"]);

    public CommodityEdit()
    {
        InitializeComponent();

    }

    private void button1_Click(object sender, EventArgs e)
    {
        try
        {
           MyConnection.Open();
        }
        catch (Exception)
        {

            throw;
        }