63 lines
2.2 KiB
C#
63 lines
2.2 KiB
C#
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using System;
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using System.Collections.Generic;
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using System.Linq.Expressions;
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using System.Reflection;
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using System.Text;
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namespace APT.Infrastructure.EF.Extensions
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{
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public class IQueryableSelectorExtension
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{
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public static Expression<Func<TSource, TResult>> CreateSelecter<TSource, TResult>(List<string> columns)
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{
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Expression<Func<TSource, TResult>> selector = null;
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//(rec)
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ParameterExpression param = Expression.Parameter(typeof(TSource), "rec");
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//new ParadigmSearchListData
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var v0 = Expression.New(typeof(TResult));
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var memberBindings = new List<MemberBinding>();
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foreach (var column in columns)
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{
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var left = typeof(TResult).GetProperty(column);
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var right = Expression.Property(param, typeof(TSource).GetProperty(column));
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memberBindings.Add(Expression.Bind(left, right));
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}
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Expression body = Expression.MemberInit(v0,
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//{ Number = rec.NUMBER, Name = rec.RES_NAME }
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memberBindings.ToArray());
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selector = (Expression<Func<TSource, TResult>>)Expression.Lambda(body, param);
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return selector;
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}
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private static MemberAssignment GetPropertyLambdaExpression(ParameterExpression param, string field)
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{
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string[] propertyNames = field.Split('.');
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Expression propertyAccess = param;
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Type type = param.Type;
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PropertyInfo property;
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foreach (string propertyName in propertyNames)
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{
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property = type.GetProperty(propertyName);
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if (property != null)
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{
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type = property.PropertyType;
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propertyAccess = Expression.MakeMemberAccess(propertyAccess, property);
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}
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}
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//var left = typeof(TResult).GetProperty(column);
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//return Expression.Bind(property, Expression.Lambda(propertyAccess, param));
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//return Expression.Lambda(propertyAccess, param);
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return null;
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}
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}
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}
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