LabelExpression.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / Microsoft / Scripting / Ast / LabelExpression.cs / 1305376 / LabelExpression.cs
                        

                        
                            /* **************************************************************************** 
 *
 * 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.Diagnostics; 
 
namespace System.Linq.Expressions {
    ///  
    /// Represents a label, which can be placed in any  context. If
    /// it is jumped to, it will get the value provided by the corresponding
    /// . Otherwise, it gets the value in . If the
    ///  equals System.Void, no value should be provided. 
    /// 
#if !SILVERLIGHT 
    [DebuggerTypeProxy(typeof(Expression.LabelExpressionProxy))] 
#endif
    public sealed class LabelExpression : Expression { 
        private readonly Expression _defaultValue;
        private readonly LabelTarget _target;

        internal LabelExpression(LabelTarget label, Expression defaultValue) { 
            _target = label;
            _defaultValue = defaultValue; 
        } 

        ///  
        /// Gets the static type of the expression that this  represents. (Inherited from .)
        /// 
        /// The  that represents the static type of the expression.
        public sealed override Type Type { 
            get { return _target.Type; }
        } 
 
        /// 
        /// Returns the node type of this . (Inherited from .) 
        /// 
        /// The  that represents this expression.
        public sealed override ExpressionType NodeType {
            get { return ExpressionType.Label; } 
        }
 
        ///  
        /// The  which this label is associated with.
        ///  
        public LabelTarget Target {
            get { return _target; }
        }
 
        /// 
        /// The value of the  when the label is reached through 
        /// normal control flow (e.g. is not jumped to). 
        /// 
        public Expression DefaultValue { 
            get { return _defaultValue; }
        }

        ///  
        /// Dispatches to the specific visit method for this node type.
        ///  
        protected internal override Expression Accept(ExpressionVisitor visitor) { 
            return visitor.VisitLabel(this);
        } 

        /// 
        /// 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.
        ///  
        /// The  property of the result. 
        /// The  property of the result.
        /// This expression if no children changed, or an expression with the updated children. 
        public LabelExpression Update(LabelTarget target, Expression defaultValue) {
            if (target == Target && defaultValue == DefaultValue) {
                return this;
            } 
            return Expression.Label(target, defaultValue);
        } 
    } 

    public partial class Expression { 
        /// 
        /// Creates a  representing a label with no default value.
        /// 
        /// The  which this  will be associated with. 
        /// A  with no default value.
        public static LabelExpression Label(LabelTarget target) { 
            return Label(target, null); 
        }
 
        /// 
        /// Creates a  representing a label with the given default value.
        /// 
        /// The  which this  will be associated with. 
        /// The value of this  when the label is reached through normal control flow.
        /// A  with the given default value. 
        public static LabelExpression Label(LabelTarget target, Expression defaultValue) { 
            ValidateGoto(target, ref defaultValue, "label", "defaultValue");
            return new LabelExpression(target, defaultValue); 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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