VariableReference.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 / cdf / src / NetFx40 / System.Activities / System / Activities / Expressions / VariableReference.cs / 1305376 / VariableReference.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------

namespace System.Activities.Expressions 
{
    using System.Linq.Expressions; 
    using System.Runtime; 

    public sealed class VariableReference : CodeActivity>, IExpressionContainer 
    {
        public VariableReference()
            : base()
        { 
        }
 
        public VariableReference(Variable variable) 
            : base()
        { 
            this.Variable = variable;
        }

        public Variable Variable 
        {
            get; 
            set; 
        }
 
        Expression IExpressionContainer.Expression
        {
            get
            { 
                return ExpressionUtilities.CreateIdentifierExpression(this.Variable);
            } 
        } 

        protected override void CacheMetadata(CodeActivityMetadata metadata) 
        {
            if (this.Variable == null)
            {
                metadata.AddValidationError(SR.VariableMustBeSet); 
            }
            else 
            { 
                if (!(this.Variable is Variable))
                { 
                    metadata.AddValidationError(SR.VariableTypeInvalid(this.Variable, typeof(T), this.Variable.Type));
                }

                if (!this.Variable.IsInTree) 
                {
                    metadata.AddValidationError(SR.VariableShouldBeOpen(this.Variable.Name)); 
                } 

                if (!metadata.Environment.IsVisible(this.Variable)) 
                {
                    metadata.AddValidationError(SR.VariableNotVisible(this.Variable.Name));
                }
 
                if (VariableModifiersHelper.IsReadOnly(Variable.Modifiers))
                { 
                    metadata.AddValidationError(SR.VariableIsReadOnly(this.Variable.Name)); 
                }
            } 
        }

        public override string ToString()
        { 
            if (Variable != null && !string.IsNullOrEmpty(Variable.Name))
            { 
                return Variable.Name; 
            }
 
            return base.ToString();
        }

        internal override bool TryGetValue(ActivityContext context, out Location value) 
        {
            try 
            { 
                context.AllowChainedEnvironmentAccess = true;
                value = context.GetLocation(this.Variable); 
            }
            finally
            {
                context.AllowChainedEnvironmentAccess = false; 
            }
 
            return true; 
        }
 
        protected override Location Execute(CodeActivityContext context)
        {
            return ExecuteWithTryGetValue(context);
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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