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/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Apache License, Version 2.0. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Apache License, Version 2.0, please send an email to
* dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
* by the terms of the Apache License, Version 2.0.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Dynamic.Utils;
using System.Reflection;
using System.Runtime.CompilerServices;
#if SILVERLIGHT
using System.Core;
#endif
#if CLR2
namespace Microsoft.Scripting.Ast {
#else
namespace System.Linq.Expressions {
#endif
/// <summary>
/// Represents a constructor call that has a collection initializer.
/// </summary>
/// <remarks>
/// Use the <see cref="M:ListInit"/> factory methods to create a ListInitExpression.
/// The value of the NodeType property of a ListInitExpression is ListInit.
/// </remarks>
#if !SILVERLIGHT
[DebuggerTypeProxy(typeof(Expression.ListInitExpressionProxy))]
#endif
public sealed class ListInitExpression : Expression {
private readonly NewExpression _newExpression;
private readonly ReadOnlyCollection<ElementInit> _initializers;
internal ListInitExpression(NewExpression newExpression, ReadOnlyCollection<ElementInit> initializers) {
_newExpression = newExpression;
_initializers = initializers;
}
/// <summary>
/// Returns the node type of this <see cref="Expression"/>. (Inherited from <see cref="Expression" />.)
/// </summary>
/// <returns>The <see cref="ExpressionType"/> that represents this expression.</returns>
public sealed override ExpressionType NodeType {
get { return ExpressionType.ListInit; }
}
/// <summary>
/// Gets the static type of the expression that this <see cref="Expression" /> represents. (Inherited from <see cref="Expression"/>.)
/// </summary>
/// <returns>The <see cref="Type"/> that represents the static type of the expression.</returns>
public sealed override Type Type {
get { return _newExpression.Type; }
}
/// <summary>
/// Gets a value that indicates whether the expression tree node can be reduced.
/// </summary>
public override bool CanReduce {
get {
return true;
}
}
/// <summary>
/// Gets the expression that contains a call to the constructor of a collection type.
/// </summary>
public NewExpression NewExpression {
get { return _newExpression; }
}
/// <summary>
/// Gets the element initializers that are used to initialize a collection.
/// </summary>
public ReadOnlyCollection<ElementInit> Initializers {
get { return _initializers; }
}
/// <summary>
/// Dispatches to the specific visit method for this node type.
/// </summary>
protected internal override Expression Accept(ExpressionVisitor visitor) {
return visitor.VisitListInit(this);
}
/// <summary>
/// Reduces the binary expression node to a simpler expression.
/// If CanReduce returns true, this should return a valid expression.
/// This method is allowed to return another node which itself
/// must be reduced.
/// </summary>
/// <returns>The reduced expression.</returns>
public override Expression Reduce() {
return MemberInitExpression.ReduceListInit(_newExpression, _initializers, true);
}
/// <summary>
/// Creates a new expression that is like this one, but using the
/// supplied children. If all of the children are the same, it will
/// return this expression.
/// </summary>
/// <param name="newExpression">The <see cref="NewExpression" /> property of the result.</param>
/// <param name="initializers">The <see cref="Initializers" /> property of the result.</param>
/// <returns>This expression if no children changed, or an expression with the updated children.</returns>
public ListInitExpression Update(NewExpression newExpression, IEnumerable<ElementInit> initializers) {
if (newExpression == NewExpression && initializers == Initializers) {
return this;
}
return Expression.ListInit(newExpression, initializers);
}
}
public partial class Expression {
/// <summary>
/// Creates a <see cref="ListInitExpression"/> that uses a method named "Add" to add elements to a collection.
/// </summary>
/// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>
/// <param name="initializers">An array of <see cref="Expression"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>
/// <returns>A <see cref="ListInitExpression"/> that has the <see cref="P:ListInitExpression.NodeType"/> property equal to ListInit and the <see cref="P:ListInitExpression.NewExpression"/> property set to the specified value.</returns>
public static ListInitExpression ListInit(NewExpression newExpression, params Expression[] initializers) {
ContractUtils.RequiresNotNull(newExpression, "newExpression");
ContractUtils.RequiresNotNull(initializers, "initializers");
return ListInit(newExpression, initializers as IEnumerable<Expression>);
}
/// <summary>
/// Creates a <see cref="ListInitExpression"/> that uses a method named "Add" to add elements to a collection.
/// </summary>
/// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>
/// <param name="initializers">An <see cref="IEnumerable{T}"/> that contains <see cref="M:ElementInit"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>
/// <returns>A <see cref="ListInitExpression"/> that has the <see cref="P:ListInitExpression.NodeType"/> property equal to ListInit and the <see cref="P:ListInitExpression.NewExpression"/> property set to the specified value.</returns>
public static ListInitExpression ListInit(NewExpression newExpression, IEnumerable<Expression> initializers) {
ContractUtils.RequiresNotNull(newExpression, "newExpression");
ContractUtils.RequiresNotNull(initializers, "initializers");
var initializerlist = initializers.ToReadOnly();
if (initializerlist.Count == 0) {
throw Error.ListInitializerWithZeroMembers();
}
MethodInfo addMethod = FindMethod(newExpression.Type, "Add", null, new Expression[] { initializerlist[0] }, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic);
return ListInit(newExpression, addMethod, initializers);
}
/// <summary>
/// Creates a <see cref="ListInitExpression"/> that uses a specified method to add elements to a collection.
/// </summary>
/// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>
/// <param name="addMethod">A <see cref="MethodInfo"/> that represents an instance method named "Add" (case insensitive), that adds an element to a collection. </param>
/// <param name="initializers">An array of <see cref="Expression"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>
/// <returns>A <see cref="ListInitExpression"/> that has the <see cref="P:ListInitExpression.NodeType"/> property equal to ListInit and the <see cref="P:ListInitExpression.NewExpression"/> property set to the specified value.</returns>
public static ListInitExpression ListInit(NewExpression newExpression, MethodInfo addMethod, params Expression[] initializers) {
if (addMethod == null) {
return ListInit(newExpression, initializers as IEnumerable<Expression>);
}
ContractUtils.RequiresNotNull(newExpression, "newExpression");
ContractUtils.RequiresNotNull(initializers, "initializers");
return ListInit(newExpression, addMethod, initializers as IEnumerable<Expression>);
}
/// <summary>
/// Creates a <see cref="ListInitExpression"/> that uses a specified method to add elements to a collection.
/// </summary>
/// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>
/// <param name="addMethod">A <see cref="MethodInfo"/> that represents an instance method named "Add" (case insensitive), that adds an element to a collection. </param>
/// <param name="initializers">An <see cref="IEnumerable{T}"/> that contains <see cref="Expression"/> objects to use to populate the Initializers collection.</param>
/// <returns>A <see cref="ListInitExpression"/> that has the <see cref="P:ListInitExpression.NodeType"/> property equal to ListInit and the <see cref="P:ListInitExpression.NewExpression"/> property set to the specified value.</returns>
public static ListInitExpression ListInit(NewExpression newExpression, MethodInfo addMethod, IEnumerable<Expression> initializers) {
if (addMethod == null) {
return ListInit(newExpression, initializers);
}
ContractUtils.RequiresNotNull(newExpression, "newExpression");
ContractUtils.RequiresNotNull(initializers, "initializers");
var initializerlist = initializers.ToReadOnly();
if (initializerlist.Count == 0) {
throw Error.ListInitializerWithZeroMembers();
}
ElementInit[] initList = new ElementInit[initializerlist.Count];
for (int i = 0; i < initializerlist.Count; i++) {
initList[i] = ElementInit(addMethod, initializerlist[i]);
}
return ListInit(newExpression, new TrueReadOnlyCollection<ElementInit>(initList));
}
/// <summary>
/// Creates a <see cref="ListInitExpression"/> that uses specified <see cref="M:ElementInit"/> objects to initialize a collection.
/// </summary>
/// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>
/// <param name="initializers">An array that contains <see cref="M:ElementInit"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>
/// <returns>
/// A <see cref="ListInitExpression"/> that has the <see cref="P:Expressions.NodeType"/> property equal to ListInit
/// and the <see cref="P:ListInitExpression.NewExpression"/> and <see cref="P:ListInitExpression.Initializers"/> properties set to the specified values.
/// </returns>
/// <remarks>
/// The <see cref="P:Expressions.Type"/> property of <paramref name="newExpression"/> must represent a type that implements <see cref="System.Collections.IEnumerable"/>.
/// The <see cref="P:Expressions.Type"/> property of the resulting <see cref="ListInitExpression"/> is equal to newExpression.Type.
/// </remarks>
public static ListInitExpression ListInit(NewExpression newExpression, params ElementInit[] initializers) {
return ListInit(newExpression, (IEnumerable<ElementInit>)initializers);
}
/// <summary>
/// Creates a <see cref="ListInitExpression"/> that uses specified <see cref="M:ElementInit"/> objects to initialize a collection.
/// </summary>
/// <param name="newExpression">A <see cref="NewExpression"/> to set the <see cref="P:ListInitExpression.NewExpression"/> property equal to.</param>
/// <param name="initializers">An <see cref="IEnumerable{T}"/> that contains <see cref="M:ElementInit"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</param>
/// <returns>An <see cref="IEnumerable{T}"/> that contains <see cref="M:ElementInit"/> objects to use to populate the <see cref="ListInitExpression.Initializers"/> collection.</returns>
/// <remarks>
/// The <see cref="P:Expressions.Type"/> property of <paramref name="newExpression"/> must represent a type that implements <see cref="System.Collections.IEnumerable"/>.
/// The <see cref="P:Expressions.Type"/> property of the resulting <see cref="ListInitExpression"/> is equal to newExpression.Type.
/// </remarks>
public static ListInitExpression ListInit(NewExpression newExpression, IEnumerable<ElementInit> initializers) {
ContractUtils.RequiresNotNull(newExpression, "newExpression");
ContractUtils.RequiresNotNull(initializers, "initializers");
var initializerlist = initializers.ToReadOnly();
if (initializerlist.Count == 0) {
throw Error.ListInitializerWithZeroMembers();
}
ValidateListInitArgs(newExpression.Type, initializerlist);
return new ListInitExpression(newExpression, initializerlist);
}
}
}
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