How to implement like post functionality of facebook

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C#

ASP.NET

I have used https://developers.facebook.com/docs/plugins/like-button for generating like button. But like button provided by developer facebook is for only page. I want to implement like functionality for particular post using facebook c# sdk.

I write below code -

dynamic userTokenResult = client.Get("oauth/access_token", new
{
    client_id = strAppID,
    client_secret = strSecret,
    grant_type = "client_credentials"
});
dynamic res = client.Post("me/og.likes", new
{
    @object = "https://www.facebook.com/yourpagename/photos/photoid/?type=3&theater"
});

I am getting below error -
(OAuthException - #2500) An active access token must be used to query information about the current user.

Can you please help me on this?