yield keyword
Thursday, October 29th, 2009近期因為睇 ASP.net MVC 既 example, 中途見到 yield keyword 既 usage, 感覺上幾好用, 以學多個 keyword 既原則黎講, 我當然會在 project 中試用, 當中既 validation 用法我覺得幾好.
public partial class Dinner {
public bool IsHostedBy(string userName) {
return HostedBy.Equals(userName, StringComparison.InvariantCultureIgnoreCase);
}
public bool IsValid {
get { return (GetRuleViolations().Count() == 0); }
}
public IEnumerable<RuleViolation> GetRuleViolations() {
if (String.IsNullOrEmpty(Title))
yield return new RuleViolation("Title is required", "Title");
if (String.IsNullOrEmpty(Description))
yield return new RuleViolation("Description is required", "Description");
if (String.IsNullOrEmpty(HostedBy))
yield return new RuleViolation("HostedBy is required", "HostedBy");
if (String.IsNullOrEmpty(Address))
yield return new RuleViolation("Address is required", "Address");
if (String.IsNullOrEmpty(Country))
yield return new RuleViolation("Country is required", "Address");
if (String.IsNullOrEmpty(ContactPhone))
yield return new RuleViolation("Phone# is required", "ContactPhone");
if (!PhoneValidator.IsValidNumber(ContactPhone, Country))
yield return new RuleViolation("Phone# does not match country", "ContactPhone");
yield break;
}
}
但當我想在 project 度用果時, 開始感覺到麻煩, 因為本身個 project 係要在 .net 2.0 既環境下運作, 而 IEnumerable
