使用 C # (. NET)以编程方式更改 web.config

Here it is some code:

var configuration = WebConfigurationManager.OpenWebConfiguration("~");
var section = (ConnectionStringsSection)configuration.GetSection("connectionStrings");
section.ConnectionStrings["MyConnectionString"].ConnectionString = "Data Source=...";
configuration.Save();

See more examples in this article, you may need to take a look to impersonation.

Configuration config = System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
ConnectionStringsSection section = config.GetSection("connectionStrings") as ConnectionStringsSection;
//section.SectionInformation.UnprotectSection();
section.SectionInformation.ProtectSection("DataProtectionConfigurationProvider");
config.Save();

Since web.config file is xml file you can open web.config using xmldocument class. Get the node from that xml file that you want to update and then save xml file.

here is URL that explains in more detail how you can update web.config file programmatically.

http://patelshailesh.com/index.php/update-web-config-programmatically

Note: if you make any changes to web.config, ASP.NET detects that changes and it will reload your application(recycle application pool) and effect of that is data kept in Session, Application, and Cache will be lost (assuming session state is InProc and not using a state server or database).

This is a method that I use to update AppSettings, works for both web and desktop applications. If you need to edit connectionStrings you can get that value from System.Configuration.ConnectionStringSettings config = configFile.ConnectionStrings.ConnectionStrings["YourConnectionStringName"]; and then set a new value with config.ConnectionString = "your connection string";. Note that if you have any comments in the connectionStrings section in Web.Config these will be removed.

private void UpdateAppSettings(string key, string value)
{
System.Configuration.Configuration configFile = null;
if (System.Web.HttpContext.Current != null)
{
configFile =
System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration("~");
}
else
{
configFile =
ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
}
var settings = configFile.AppSettings.Settings;
if (settings[key] == null)
{
settings.Add(key, value);
}
else
{
settings[key].Value = value;
}
configFile.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection(configFile.AppSettings.SectionInformation.Name);
}