在 C# 运行时读取、写入和更新 app.config 文件中的连接字符串

Question

我为连接设置创建了一个表单，用户可以在其中更新服务器名称、数据库以及用户 ID 和密码。我已将连接字符串存储在 app.config 文件中。

我的问题是，如何在运行时更新app.config文件中的连接字符串以及如何在第一时间通过表单上的文本框更改连接字符串的信息，文本框将显示信息第一次后的服务器名、id、密码

这里是我的 app.config

    <?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
        <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" >
            <section name="Data123.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" allowExeDefinition="MachineToLocalUser" requirePermission="false" />
        </sectionGroup>   
    </configSections>
  <connectionStrings>
   <add name="Data123Entities" connectionString="metadata=res://*/Data123DB.csdl|res://*/Data123DB.ssdl|res://*/Data123DB.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=nguyenduyhai;initial catalog=Data123;persist security info=True;user id=sa;password=1234567;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />
    <!--<add name="Data123Entities" connectionString="metadata=res://*/Data123DB.csdl|res://*/Data123DB.ssdl|res://*/Data123DB.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=NGUYENDUYHAI\SQLEXPRESS;initial catalog=Data123;persist security info=True;user id=sa;password=1234567;MultipleActiveResultSets=True;App=EntityFramework&quot;" providerName="System.Data.EntityClient" />-->
  </connectionStrings>
</configuration>

这里是我正在尝试但不起作用的代码，请帮助我

     void saveconect(string address,string id,string pass)
{

            var config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
            var connectionStringsSection = (ConnectionStringsSection)config.GetSection("connectionStrings");
            connectionStringsSection.ConnectionStrings["Data123Entities"].ConnectionString = "data source=" + address + ";initial catalog=" + "Data123" + ";user id=" + id + ";password=" + pass + "";
            config.Save(ConfigurationSaveMode.Modified, true);
            ConfigurationManager.RefreshSection("connectionStrings");
}




 private void buttonUpdate_Click(object sender, EventArgs e)
    {


        saveconect(textboxServerAddress.Text, textBoxUserID.Text, textBoxPassword.Text);
    }

Answer 1

您是否尝试在发布文件夹中运行应用程序？ 因为在 Debug 模式下不会改变。

Answer 2

使用 System.Xml.Linq; 会是这样的：

var doc = XElement.Load(fileName); 
var target = doc.Element("configuration").Elements("configurationStrings").Where(e => e.Element("name").Value == "Data123Entities").Single(); 
target.Element("connectionString").Value = "metadata=res://*/Data123DB.csdl|res://*/Data123DB.ssdl|res://*/Data123DB.msl;provider=System.Data.SqlClient;provider connection string="data source=" + dataSource + ";initial catalog=" + initCatalog + ";persist security info=True;user id=sa;password=1234567;MultipleActiveResultSets=True;App=EntityFramework""
doc.Save(fileName);