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EF IQueryable OrderBy string Extension

EF 에서 문자열로 정렬 컬럼 지정하고 싶을때 사용하면 됩니다.

Source

public static class IQueryableExtensions
{
    public static IQueryable<T> OrderBy<T>(this IQueryable<T> source, string ordering, params object[] values)
    {
        var resultExp = CreateMethodCallExpression(source, "OrderBy", ordering);
        return source.Provider.CreateQuery<T>(resultExp);
    }

    public static IQueryable<T> OrderByDescending<T>(this IQueryable<T> source, string ordering, params object[] values)
    {
        var resultExp = CreateMethodCallExpression(source, "OrderByDescending", ordering);
        return source.Provider.CreateQuery<T>(resultExp);
    }

    public static IQueryable<T> ThenBy<T>(this IQueryable<T> source, string ordering, params object[] values)
    {
        var resultExp = CreateMethodCallExpression(source, "ThenBy", ordering);
        return source.Provider.CreateQuery<T>(resultExp);
    }

    public static IQueryable<T> ThenByDescending<T>(this IQueryable<T> source, string ordering, params object[] values)
    {
        var resultExp = CreateMethodCallExpression(source, "ThenByDescending", ordering);
        return source.Provider.CreateQuery<T>(resultExp);
    }

    private static MethodCallExpression CreateMethodCallExpression<T>(IQueryable<T> source, string methodName, string ordering)
    {
        var strings = ordering.Split('.');

        var types = new List<Type>();
        var properties = new List<PropertyInfo>();
        var propertyAccesses = new List<MemberExpression>();

        types.Add(typeof(T));

        for (int i = 0; i < strings.Length; i++)
        {
            if (i != 0)
                types.Add(properties[i - 1].PropertyType);

            properties.Add(types[i].GetProperty(strings[i]));
        }

        var parameter = Expression.Parameter(types[0], "p");

        for (int i = 0; i < properties.Count; i++)
        {
            propertyAccesses.Add(i == 0
                ? Expression.MakeMemberAccess(parameter, properties[i])
                : Expression.MakeMemberAccess(propertyAccesses[i - 1], properties[i]));
        }

        var orderByExp = Expression.Lambda(propertyAccesses.Last(), parameter);

        return Expression.Call(typeof(Queryable), methodName,
            new Type[] { types.First(), properties.Last().PropertyType }, source.Expression, Expression.Quote(orderByExp));
    }
}

Example

_db.Entities.OrderBy("ComplexType.Property1").ThenByDescending("ComplexType.Property2");

Author: Joseph Kwon

Submitted on: 4 feb 2016

Language: C#

Type: System.Linq.IQueryable<out T>

Views: 2479