Web读取指定的config文件的内容

需求:

什么时候会用到动态改变Web.config内的值?
在Web.config定义了一个全局设置值A,因为程序运行中满足了某个条件,要将A的值改变

Web.config中定义:

  <appSettings>
    <add key="IsChangeDb" value="false"/>
  </appSettings>

获取Web.config中指定配置:

//获取web.config中 定义在appSetting中定义的配置
var item = ConfigurationManager.AppSettings["IsChangeDb"];

//根据我自己的需要转换成bool值
bool isChangeDb = string.IsNullOrEmpty(ConfigurationManager.AppSettings["IsChangeDb"]) ? false : bool.Parse(ConfigurationManager.AppSettings["IsChangeDb"]);

代码中更改Web.config中指定配置:


Configuration config=System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
config.AppSettings.Settings.Remove("IsChangeDb");
config.AppSettings.Settings.Add("IsChangeDb", "true");
config.Save();

参考资料:

http://stackoverflow.com/questions/719928/how-do-you-modify-the-web-config-appsettings-at-runtime

出处：https://blog.csdn.net/qq_32452623/article/details/53580093

============================================================================

asp.net2.0新添加了对web.config直接操作的功能。开发的时候有可能用到在web.config里设置配置文件，其实是可以通过程序来设置这些配置节的。

asp.net2.0需要添加引用：

using System.Web.Configuration;

web.config里的配置节：

（1）读

string filepath = ConfigurationManager.AppSettings["FilePath"];

（2）添加

        Configuration config = WebConfigurationManager.OpenWebConfiguration("/WebConfigManager");
        AppSettingsSection app = config.AppSettings;
        app.Settings.Add("p", "p:\");
        config.Save(ConfigurationSaveMode.Modified);

（3）修改

          Configuration config = WebConfigurationManager.OpenWebConfiguration("/WebConfigManager");
            AppSettingsSection app = config.AppSettings;
            app.Settings["p"].Value = @"g:";
            config.Save(ConfigurationSaveMode.Modified);

（4）删除

Configuration config = WebConfigurationManager.OpenWebConfiguration("/WebConfigManager");
        AppSettingsSection app = config.AppSettings;
        app.Settings.Remove("p");
        config.Save(ConfigurationSaveMode.Modified);

注意：

（1）asp.net用户需要有读取、修改、写入的权限。

（2）WebConfigManager是web.config所在的文件夹名。

出处：https://www.cnblogs.com/xxtkong/archive/2011/10/14/2211793.html

==============================================================================

通过从网上的了解，和学习，我们看到ConfigurationManager.OpenMappedExeConfiguration这个方法可以用于打开指定的配置文件，那么看看我们用它来做一些事情吧，下面看代码：

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web.Configuration;



namespace PVG.Lib.Configs
{
    public class WebConfigHelper
    {
        /// <summary>
        /// 是否加密连接字符串
        /// </summary>
        public bool IsEncryptionConnection { get; set; }

        private Configuration config = null;
        public Configuration Configuration
        {
            get { return config; }
            set { config = value; }
        }



        public WebConfigHelper()
        {
            config = WebConfigurationManager.OpenWebConfiguration("~");
        }


        /// <summary>
        /// 读取ConnectionStrings
        /// </summary>
        /// <param name="ConnName"></param>
        /// <returns></returns>
        public string GetConnectionStrings(string ConnName)
        {
            string res = "";
            if (config != null && config.ConnectionStrings.ConnectionStrings[ConnName] != null)
                res = config.ConnectionStrings.ConnectionStrings[ConnName].ConnectionString;
            return res;
        }

        public string SetConnectionStrings(string ConnName, string ConnValue)
        {
            return SetConnectionStrings(ConnName, ConnValue, "");
        }

        public string SetConnectionStrings(string ConnName, string ConnValue, string providerName)
        {
            if (config != null)
            {
                if (config.ConnectionStrings.ConnectionStrings[ConnName] != null)
                    config.ConnectionStrings.ConnectionStrings[ConnName].ConnectionString = ConnValue;
                else
                    config.ConnectionStrings.ConnectionStrings.Add(new ConnectionStringSettings(ConnName, ConnValue, providerName));
                config.Save(ConfigurationSaveMode.Modified);
            }
            if (IsEncryptionConnection)
                encryptionConn();//加密配置项
            return GetConnectionStrings(ConnName);

        }


        public string GetAppSettings(string keyName)
        {
            string res = "";
            if (config != null && config.AppSettings.Settings[keyName] != null)
                res = config.AppSettings.Settings[keyName].Value;
            return res;
        }


        public string SetAppSettings(string keyName, string keyValue)
        {
            if (config != null)
            {
                if (config.AppSettings.Settings[keyName] != null)
                    config.AppSettings.Settings[keyName].Value = keyValue;
                else
                    config.AppSettings.Settings.Add(keyName, keyValue);
                config.Save(ConfigurationSaveMode.Modified);
            }
            return GetAppSettings(keyName);

        }


        private void encryptionConn()
        {

            ConfigurationSection connectionSection = config.GetSection("connectionStrings");
            if (connectionSection != null)
            {
                connectionSection.SectionInformation.ProtectSection("RSAProtectedConfigurationProvider");
                config.Save();
            }
        }

    }
}

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