Get Mail Setting from Web.Config in SendAsync Method? - asp.net-mvc

Question

I am working on Forgot Password Functionality. In my web.config file I have done the mail settings:
<system.net>
<mailSettings>
<smtp from="email">
<network host="host" port="25" userName="" password="=" enableSsl="true" />
</smtp>
</mailSettings>
</system.net>
In my SendAsync method I am trying to read setting from web.config:
SmtpClient client = new SmtpClient();
return client.SendMailAsync(ConfigurationManager.AppSettings["SupportEmailAddr"],
message.Destination,
message.Subject,
message.Body);
I have no idea what is this: AppSettings["SupportEmailAddr"]
I took this from here.
It is giving me following exception:
Value cannot be null. Parameter name: from

Answer 1

In your web.config file you have a section called: <appSettings>.
That is what ConfigurationManager.AppSettings is referring too.
["SupportEmailAddr"] is looking at a specific setting called SupportEmailAddr.
In your web.config it would look something like this:
<appSettings>
<add key="SupportEmailAddr" value="someone#example.com" />
</appSettings>
You are getting the value cannot be null message because you will not have the setting in your web.config as above.
So to fix the error message find your <appSettings> and add:
<add key="SupportEmailAddr" value="someone#example.com" />
Alternatively, if you have the current value in your AppSettings already then just change the key that you are looking for in the C# code.
ConfigurationManager.AppSettings["CorrectAppSettingKey"]
Note: if you plan on using any of the web.config inheritance features you should WebConfiguratonManger.AppSettings instead of ConfigurationManager.AppSettings. See the difference between the two here: What's the difference between the WebConfigurationManager and the ConfigurationManager?