Add following code in a “.cs” files and start using
//Copyright (C) Microsoft Corporation. All rights reserved.
using System;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Reflection.Emit;
using System.Threading;
using System.Collections;
namespace System.Linq.Dynamic
{
public static class DynamicQueryable
{
public static IQueryable Join(this IQueryable outer, IEnumerable inner, string outerSelector, string innerSelector, string resultsSelector, params object[] values)
{
if (inner == null) throw new ArgumentNullException("inner");
if (outerSelector == null) throw new ArgumentNullException("outerSelector");
if (innerSelector == null) throw new ArgumentNullException("innerSelector");
if (resultsSelector == null) throw new ArgumentNullException("resultsSelctor");
LambdaExpression outerSelectorLambda = DynamicExpression.ParseLambda(outer.ElementType, null, outerSelector, values);
LambdaExpression innerSelectorLambda = DynamicExpression.ParseLambda(inner.AsQueryable().ElementType, null, innerSelector, values);
ParameterExpression[] parameters = new ParameterExpression[] {
Expression.Parameter(outer.ElementType, "outer"), Expression.Parameter(inner.AsQueryable().ElementType, "inner") };
LambdaExpression resultsSelectorLambda = DynamicExpression.ParseLambda(parameters, null, resultsSelector, values);
return outer.Provider.CreateQuery(
Expression.Call(
typeof(Queryable), "Join",
new Type[] { outer.ElementType, inner.AsQueryable().ElementType, outerSelectorLambda.Body.Type, resultsSelectorLambda.Body.Type },
outer.Expression, inner.AsQueryable().Expression, Expression.Quote(outerSelectorLambda), Expression.Quote(innerSelectorLambda), Expression.Quote(resultsSelectorLambda)));
}
//The generic overload.
public static IQueryable<T> Join<T>(this IQueryable<T> outer, IEnumerable<T> inner, string outerSelector, string innerSelector, string resultsSelector, params object[] values)
{
return (IQueryable<T>)Join((IQueryable)outer, (IEnumerable)inner, outerSelector, innerSelector, resultsSelector, values);
}
public static IQueryable<T> Where<T>(this IQueryable<T> source, string predicate, params object[] values)
{
return (IQueryable<T>)Where((IQueryable)source, predicate, values);
}
public static IQueryable Where(this IQueryable source, string predicate, params object[] values)
{
if (source == null) throw new ArgumentNullException("source");
if (predicate == null) throw new ArgumentNullException("predicate");
LambdaExpression lambda = DynamicExpression.ParseLambda(source.ElementType, typeof(bool), predicate, values);
return source.Provider.CreateQuery(
Expression.Call(
typeof(Queryable), "Where",
new Type[] { source.ElementType },
source.Expression, Expression.Quote(lambda)));
}
public static IQueryable Select(this IQueryable source, string selector, params object[] values)
{
if (source == null) throw new ArgumentNullException("source");
if (selector == null) throw new ArgumentNullException("selector");
LambdaExpression lambda = DynamicExpression.ParseLambda(source.ElementType, null, selector, values);
return source.Provider.CreateQuery(
Expression.Call(
typeof(Queryable), "Select",
new Type[] { source.ElementType, lambda.Body.Type },
source.Expression, Expression.Quote(lambda)));
}
public static IQueryable<T> OrderBy<T>(this IQueryable<T> source, string ordering, params object[] values)
{
return (IQueryable<T>)OrderBy((IQueryable)source, ordering, values);
}
public static IQueryable OrderBy(this IQueryable source, string ordering, params object[] values)
{
if (source == null) throw new ArgumentNullException("source");
if (ordering == null) throw new ArgumentNullException("ordering");
ParameterExpression[] parameters = new ParameterExpression[] {
Expression.Parameter(source.ElementType, "") };
ExpressionParser parser = new ExpressionParser(parameters, ordering, values);
IEnumerable<DynamicOrdering> orderings = parser.ParseOrdering();
Expression queryExpr = source.Expression;
string methodAsc = "OrderBy";
string methodDesc = "OrderByDescending";
foreach (DynamicOrdering o in orderings)
{
queryExpr = Expression.Call(
typeof(Queryable), o.Ascending ? methodAsc : methodDesc,
new Type[] { source.ElementType, o.Selector.Type },
queryExpr, Expression.Quote(Expression.Lambda(o.Selector, parameters)));
methodAsc = "ThenBy";
methodDesc = "ThenByDescending";
}
return source.Provider.CreateQuery(queryExpr);
}
public static IQueryable Take(this IQueryable source, int count)
{
if (source == null) throw new ArgumentNullException("source");
return source.Provider.CreateQuery(
Expression.Call(
typeof(Queryable), "Take",
new Type[] { source.ElementType },
source.Expression, Expression.Constant(count)));
}
public static IQueryable Skip(this IQueryable source, int count)
{
if (source == null) throw new ArgumentNullException("source");
return source.Provider.CreateQuery(
Expression.Call(
typeof(Queryable), "Skip",
new Type[] { source.ElementType },
source.Expression, Expression.Constant(count)));
}
public static IQueryable<T> GroupBy<T>(this IQueryable source, string keySelector, string elementSelector, params object[] values)
{
if (source == null) throw new ArgumentNullException("source");
if (keySelector == null) throw new ArgumentNullException("keySelector");
if (elementSelector == null) throw new ArgumentNullException("elementSelector");
LambdaExpression keyLambda = DynamicExpression.ParseLambda(source.ElementType, null, keySelector, values);
LambdaExpression elementLambda = DynamicExpression.ParseLambda(source.ElementType, null, elementSelector, values);
return source.Provider.CreateQuery<T>(
Expression.Call(
typeof(Queryable), "GroupBy",
new Type[] { source.ElementType, keyLambda.Body.Type, elementLambda.Body.Type },
source.Expression, Expression.Quote(keyLambda), Expression.Quote(elementLambda)));
}
public static IQueryable GroupBy(this IQueryable source, string keySelector, string elementSelector, params object[] values)
{
if (source == null) throw new ArgumentNullException("source");
if (keySelector == null) throw new ArgumentNullException("keySelector");
if (elementSelector == null) throw new ArgumentNullException("elementSelector");
LambdaExpression keyLambda = DynamicExpression.ParseLambda(source.ElementType, null, keySelector, values);
LambdaExpression elementLambda = DynamicExpression.ParseLambda(source.ElementType, null, elementSelector, values);
return source.Provider.CreateQuery(
Expression.Call(
typeof(Queryable), "GroupBy",
new Type[] { source.ElementType, keyLambda.Body.Type, elementLambda.Body.Type },
source.Expression, Expression.Quote(keyLambda), Expression.Quote(elementLambda)));
}
public static bool Any(this IQueryable source)
{
if (source == null) throw new ArgumentNullException("source");
return (bool)source.Provider.Execute(
Expression.Call(
typeof(Queryable), "Any",
new Type[] { source.ElementType }, source.Expression));
}
public static int Count(this IQueryable source)
{
if (source == null) throw new ArgumentNullException("source");
return (int)source.Provider.Execute(
Expression.Call(
typeof(Queryable), "Count",
new Type[] { source.ElementType }, source.Expression));
}
}
public abstract class DynamicClass
{
public override string ToString()
{
PropertyInfo[] props = this.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public);
StringBuilder sb = new StringBuilder();
sb.Append("{");
for (int i = 0; i < props.Length; i++)
{
if (i > 0) sb.Append(", ");
sb.Append(props[i].Name);
sb.Append("=");
sb.Append(props[i].GetValue(this, null));
}
sb.Append("}");
return sb.ToString();
}
}
public class DynamicProperty
{
string name;
Type type;
public DynamicProperty(string name, Type type)
{
if (name == null) throw new ArgumentNullException("name");
if (type == null) throw new ArgumentNullException("type");
this.name = name;
this.type = type;
}
public string Name
{
get { return name; }
}
public Type Type
{
get { return type; }
}
}
public static class DynamicExpression
{
public static Expression Parse(Type resultType, string expression, params object[] values)
{
ExpressionParser parser = new ExpressionParser(null, expression, values);
return parser.Parse(resultType);
}
public static LambdaExpression ParseLambda(Type itType, Type resultType, string expression, params object[] values)
{
return ParseLambda(new ParameterExpression[] { Expression.Parameter(itType, "") }, resultType, expression, values);
}
public static LambdaExpression ParseLambda(ParameterExpression[] parameters, Type resultType, string expression, params object[] values)
{
ExpressionParser parser = new ExpressionParser(parameters, expression, values);
return Expression.Lambda(parser.Parse(resultType), parameters);
}
public static Expression<Func<T, S>> ParseLambda<T, S>(string expression, params object[] values)
{
return (Expression<Func<T, S>>)ParseLambda(typeof(T), typeof(S), expression, values);
}
public static Type CreateClass(params DynamicProperty[] properties)
{
return ClassFactory.Instance.GetDynamicClass(properties);
}
public static Type CreateClass(IEnumerable<DynamicProperty> properties)
{
return ClassFactory.Instance.GetDynamicClass(properties);
}
}
internal class DynamicOrdering
{
public Expression Selector;
public bool Ascending;
}
internal class Signature : IEquatable<Signature>
{
public DynamicProperty[] properties;
public int hashCode;
public Signature(IEnumerable<DynamicProperty> properties)
{
this.properties = properties.ToArray();
hashCode = 0;
foreach (DynamicProperty p in properties)
{
hashCode ^= p.Name.GetHashCode() ^ p.Type.GetHashCode();
}
}
public override int GetHashCode()
{
return hashCode;
}
public override bool Equals(object obj)
{
return obj is Signature ? Equals((Signature)obj) : false;
}
public bool Equals(Signature other)
{
if (properties.Length != other.properties.Length) return false;
for (int i = 0; i < properties.Length; i++)
{
if (properties[i].Name != other.properties[i].Name ||
properties[i].Type != other.properties[i].Type) return false;
}
return true;
}
}
internal class ClassFactory
{
public static readonly ClassFactory Instance = new ClassFactory();
static ClassFactory() { } // Trigger lazy initialization of static fields
ModuleBuilder module;
Dictionary<Signature, Type> classes;
int classCount;
ReaderWriterLock rwLock;
private ClassFactory()
{
AssemblyName name = new AssemblyName("DynamicClasses");
AssemblyBuilder assembly = AppDomain.CurrentDomain.DefineDynamicAssembly(name, AssemblyBuilderAccess.Run);
#if ENABLE_LINQ_PARTIAL_TRUST
new ReflectionPermission(PermissionState.Unrestricted).Assert();
