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/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Microsoft Public License. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Microsoft Public License, 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 Microsoft Public License.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System;
using System.Dynamic.Utils;
using System.Reflection;
#if SILVERLIGHT
using System.Core;
#endif
#if CLR2
namespace Microsoft.Scripting.Ast {
#else
namespace System.Linq.Expressions {
#endif
/// <summary>
/// Represents assignment to a member of an object.
/// </summary>
public sealed class MemberAssignment : MemberBinding {
Expression _expression;
internal MemberAssignment(MemberInfo member, Expression expression)
#pragma warning disable 618
: base(MemberBindingType.Assignment, member) {
#pragma warning restore 618
_expression = expression;
}
/// <summary>
/// Gets the <see cref="Expression"/> which represents the object whose member is being assigned to.
/// </summary>
public Expression Expression {
get { return _expression; }
}
/// <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="expression">The <see cref="Expression" /> property of the result.</param>
/// <returns>This expression if no children changed, or an expression with the updated children.</returns>
public MemberAssignment Update(Expression expression) {
if (expression == Expression) {
return this;
}
return Expression.Bind(Member, expression);
}
}
public partial class Expression {
/// <summary>
/// Creates a <see cref="MemberAssignment"/> binding the specified value to the given member.
/// </summary>
/// <param name="member">The <see cref="MemberInfo"/> for the member which is being assigned to.</param>
/// <param name="expression">The value to be assigned to <paramref name="member"/>.</param>
/// <returns>The created <see cref="MemberAssignment"/>.</returns>
public static MemberAssignment Bind(MemberInfo member, Expression expression) {
ContractUtils.RequiresNotNull(member, "member");
RequiresCanRead(expression, "expression");
Type memberType;
ValidateSettableFieldOrPropertyMember(member, out memberType);
if (!memberType.IsAssignableFrom(expression.Type)) {
throw Error.ArgumentTypesMustMatch();
}
return new MemberAssignment(member, expression);
}
/// <summary>
/// Creates a <see cref="MemberAssignment"/> binding the specified value to the given property.
/// </summary>
/// <param name="propertyAccessor">The <see cref="PropertyInfo"/> for the property which is being assigned to.</param>
/// <param name="expression">The value to be assigned to <paramref name="propertyAccessor"/>.</param>
/// <returns>The created <see cref="MemberAssignment"/>.</returns>
public static MemberAssignment Bind(MethodInfo propertyAccessor, Expression expression) {
ContractUtils.RequiresNotNull(propertyAccessor, "propertyAccessor");
ContractUtils.RequiresNotNull(expression, "expression");
ValidateMethodInfo(propertyAccessor);
return Bind(GetProperty(propertyAccessor), expression);
}
private static void ValidateSettableFieldOrPropertyMember(MemberInfo member, out Type memberType) {
FieldInfo fi = member as FieldInfo;
if (fi == null) {
PropertyInfo pi = member as PropertyInfo;
if (pi == null) {
throw Error.ArgumentMustBeFieldInfoOrPropertInfo();
}
if (!pi.CanWrite) {
throw Error.PropertyDoesNotHaveSetter(pi);
}
memberType = pi.PropertyType;
} else {
memberType = fi.FieldType;
}
}
}
}
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