Example: Create visitor group criteria

10 min

(Thanks to Ted & Gustaf for this example.)

One usage scenario could be to check for a cookie that says that the visitor has previously completed a purchase on the website and is a returning customer.

Create the settings and criterion classes

Visitor group criteria require a settings class and a criterion class.

The settings class is used to persist any settings available to editors when creating visitor groups.

The criterion class contains the logic to determine whether or not a visitor belongs to the visitor group.

You should create the two classes in a suitable folder structure:

create_classes.png

Implement the settings class

The only setting required for this visitor group criterion is the cookie name you should look for.

First, make the CookieExistsCriterionSettings class inherits the CriterionModelBase class:

public class CookieExistsCriterionSettings : CriterionModelBase

Add a public property to let editors specify the cookie name:

[Required]
public string CookieName { 
  get; 
  set; 
}

If you need custom validation logic when you save a criterion, you can make your settings class implement the IValidateCriterionModel interface (this is optional). By implementing that interface’s Validate method, you can customize how you validate settings before saving a criterion for a visitor group. The abstract CriterionModelBase class requires you to implement the Copy() method. Because you are not using complex reference types, you can implement it by returning a shallow copy as shown (see Create custom visitor group criteria):

public override ICriterionModel Copy() {
  return ShallowCopy();
}

The following code shows the complete CookieExistsCriterionSettings class:

public class CookieExistsCriterionSettings: CriterionModelBase {
  [Required]
  public string CookieName {
    get;
    set;
  }

  public override ICriterionModel Copy() {
    return ShallowCopy();
  }
}

Implement the criterion class

Make the CookieExistsCriterionclass inherit the abstract CriterionBaseclass with the settings class as the type parameter:

public class CookieExistsCriterion : CriterionBase<CookieExistsCriterionSettings>

Add a VisitorGroupCriterion attribute to set the category, name, and description of your criterion (for more available VisitorGroupCriterion properties, see Create custom visitor group criteria:

[VisitorGroupCriterion(   
   Category = "Technical",
   DisplayName = "Cookie Exists",
   Description = "Checks if a specific cookie exists")]

The abstract CriterionBase class requires you to implement an IsMatch() method, which determines whether the current user matches this visitor group criterion. You should check if a specific cookie exists based on the criterion settings:

public override bool IsMatch(IPrincipal principal, HttpContextBase httpContext) {
  return httpContext.Request.Cookies[Model.CookieName] != null;
}

The criterion class displays as follows:

[VisitorGroupCriterion(
  Category = "Technical",
  DisplayName = "Cookie Exists",
  Description = "Checks if a specific cookie exists")]

public class CookieExistsCriterion: CriterionBase<CookieExistsCriterionSettings> {
  public override bool IsMatch(IPrincipal principal, HttpContextBase httpContext) {
    return httpContext.Request.Cookies[Model.CookieName] != null;
  }
}

Note You access the criterion settings instance through the Modelproperty.