■ Expression 클래스를 사용해 객체 컬렉션 특정 객체 속성 값의 집합을 구하는 방법을 보여준다. (속성 1개만 지정)
▶ Program.cs
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using System; using System.ComponentModel; using System.Collections.ObjectModel; using System.Linq; using System.Linq.Expressions; namespace TestProject { /// <summary> /// 프로그램 /// </summary> public class Program { //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Static //////////////////////////////////////////////////////////////////////////////// Private #region 프로그램 시작하기 - Main() /// <summary> /// 프로그램 시작하기 /// </summary> private static void Main() { ObservableCollection<Employee> collection = Employee.GetCollection(); string propertyName = "Sex"; ParameterExpression parameterExpression = Expression.Parameter(typeof(Employee), "p"); MemberExpression memberExpression = Expression.Property(parameterExpression, propertyName); LambdaExpression lambdaExpression = Expression.Lambda(memberExpression, parameterExpression); Delegate function = lambdaExpression.Compile(); var result = ( from item in collection group item by function.DynamicInvoke(item) into group1 select group1.First().GetType().GetProperty(propertyName).GetValue(group1.First()).ToString() into group2 orderby group2 select group2 ).ToList(); foreach(var item in result) { Console.WriteLine(item); } } #endregion } } |
▶ Employee.cs
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using System.Collections.ObjectModel; namespace TestProject { /// <summary> /// 직원 /// </summary> public class Employee { //////////////////////////////////////////////////////////////////////////////////////////////////// Property ////////////////////////////////////////////////////////////////////////////////////////// Public #region ID - ID /// <summary> /// ID /// </summary> public string ID { get; set; } #endregion #region 성명 - Name /// <summary> /// 성명 /// </summary> public string Name { get; set; } #endregion #region 성별 - Sex /// <summary> /// 성별 /// </summary> public string Sex { get; set; } #endregion //////////////////////////////////////////////////////////////////////////////////////////////////// Method ////////////////////////////////////////////////////////////////////////////////////////// Static //////////////////////////////////////////////////////////////////////////////// Public #region 컬렉션 구하기 - GetCollection() /// <summary> /// 컬렉션 구하기 /// </summary> /// <returns>컬렉션</returns> public static ObservableCollection<Employee> GetCollection() { ObservableCollection<Employee> collection = new ObservableCollection<Employee>(); for(int i = 0; i < 100000; i++) { collection.Add ( new Employee() { ID = i.ToString(), Name = "직원" + i.ToString(), Sex = (i % 3 == 1 ? "남" : "여") } ); } return collection; } #endregion } } |