Read Variable from Web.Config

How can I add and read the value from web.config file?

Solution 1:

Given the following web.config:

<appSettings>
     <add key="ClientId" value="127605460617602"/>
     <add key="RedirectUrl" value="http://localhost:49548/Redirect.aspx"/>
</appSettings>

Example usage:

using System.Configuration;

string clientId = ConfigurationManager.AppSettings["ClientId"];
string redirectUrl = ConfigurationManager.AppSettings["RedirectUrl"];

Solution 2:

I would suggest you to don't modify web.config from your, because every time when change, it will restart your application.

However you can read web.config using System.Configuration.ConfigurationManager.AppSettings

Solution 3:

If you want the basics, you can access the keys via:

string myKey = System.Configuration.ConfigurationManager.AppSettings["myKey"].ToString();
string imageFolder = System.Configuration.ConfigurationManager.AppSettings["imageFolder"].ToString();

To access my web config keys I always make a static class in my application. It means I can access them wherever I require and I'm not using the strings all over my application (if it changes in the web config I'd have to go through all the occurrences changing them). Here's a sample:

using System.Configuration;

public static class AppSettingsGet
{    
    public static string myKey
    {
        get { return ConfigurationManager.AppSettings["myKey"].ToString(); }
    }

    public static string imageFolder
    {
        get { return ConfigurationManager.AppSettings["imageFolder"].ToString(); }
    }

    // I also get my connection string from here
    public static string ConnectionString
    {
       get { return ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString; }
    }
}

Solution 4:

Assuming the key is contained inside the <appSettings> node:

ConfigurationSettings.AppSettings["theKey"];

As for "writing" - put simply, dont.

The web.config is not designed for that, if you're going to be changing a value constantly, put it in a static helper class.

Solution 5:

Ryan Farley has a great post about this in his blog, including all the reasons why not to write back into web.config files: Writing to Your .NET Application's Config File