Make Changes in Web.Config file

In this article I am going to show how we can make changes in our web.config file at run time.

If you want to add a new key in your web.config file at run time then use below code…

        Configuration config = WebConfigurationManager.OpenWebConfiguration(HttpContext.Current.Request.ApplicationPath);       
        config.AppSettings.Settings.Add(TxtYourKey.Text, TxtYourValue.Text);       
        config.Save();
        lblMsg.Text = " Successfully added new key in config file";
       TxtYourKey.Text = null;
       TxtYourValue.Text = null;

 
If you want to delete a existing key then use below code…

 Configuration config =
WebConfigurationManager.OpenWebConfiguration(HttpContext.Current.Request.ApplicationPath);
        config.AppSettings.Settings.Remove(TxtYourKey.Text);
        config.Save();
        lblMsg.Text = "key deleted from config file";
        TxtYourKey.Text = null;

 If you want to display all key in your web.config file then use below code…

Configuration configuration = WebConfigurationManager.OpenWebConfiguration("~");
AppSettingsSection appSettingsSection =
(AppSettingsSection)configuration.GetSection("appSettings");
if (appSettingsSection != null)
{
    foreach (string key in appSettingsSection.Settings.AllKeys)
    {
        Response.Write(key);
    }
} 

If you want to to modify an existing key then use below code… 

public void Modify(string key, string value)
{
    Configuration configuration = WebConfigurationManager.OpenWebConfiguration("~");
    AppSettingsSection appSettingsSection = (AppSettingsSection)configuration.GetSection("appSettings");
    if (appSettingsSection != null)
    {
        appSettingsSection.Settings[key].Value = value;
        config.Save();
    }
}