IndexerReference.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / System.Activities / System / Activities / Expressions / IndexerReference.cs / 1305376 / IndexerReference.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------

namespace System.Activities.Expressions 
{
    using System.Collections.ObjectModel; 
    using System.ComponentModel; 
    using System.Reflection;
    using System.Runtime; 
    using System.Runtime.Collections;
    using System.Runtime.Serialization;
    using System.Windows.Markup;
 
    [ContentProperty("Indices")]
    public sealed class IndexerReference : CodeActivity> 
    { 
        Collection indices;
        MethodInfo getMethod; 
        MethodInfo setMethod;

        [RequiredArgument]
        [DefaultValue(null)] 
        public InArgument Operand
        { 
            get; 
            set;
        } 

        [RequiredArgument]
        [DefaultValue(null)]
        public Collection Indices 
        {
            get 
            { 
                if (this.indices == null)
                { 
                    this.indices = new ValidatingCollection
                    {
                        // disallow null values
                        OnAddValidationCallback = item => 
                        {
                            if (item == null) 
                            { 
                                throw FxTrace.Exception.ArgumentNull("item");
                            } 
                        },
                    };
                }
                return this.indices; 
            }
        } 
 
        protected override void CacheMetadata(CodeActivityMetadata metadata)
        { 
            if (typeof(TOperand).IsValueType)
            {
                metadata.AddValidationError(SR.TargetTypeIsValueType(this.GetType().Name, this.DisplayName));
            } 
            if (this.Indices.Count == 0)
            { 
                metadata.AddValidationError(SR.IndicesAreNeeded(this.GetType().Name, this.DisplayName)); 
            }
            else 
            {
                IndexerHelper.CacheMethod(this.Indices, ref getMethod, ref setMethod);
                if (this.setMethod == null)
                { 
                    metadata.AddValidationError(SR.SpecialMethodNotFound("set_Item", typeof(TOperand).Name));
                } 
            } 

            RuntimeArgument operandArgument = new RuntimeArgument("Operand", typeof(TOperand), ArgumentDirection.In, true); 
            metadata.Bind(this.Operand, operandArgument);
            metadata.AddArgument(operandArgument);

            IndexerHelper.OnGetArguments(this.Indices, this.Result, metadata); 
        }
 
        protected override Location Execute(CodeActivityContext context) 
        {
            object[] indicesValue = new object[this.Indices.Count]; 

            for (int i = 0; i < this.Indices.Count; i++)
            {
                indicesValue[i] = this.Indices[i].Get(context); 
            }
 
            TOperand operandValue = this.Operand.Get(context); 
            if (operandValue == null)
            { 
                throw FxTrace.Exception.AsError(new InvalidOperationException(SR.MemberCannotBeNull("Operand", this.GetType().Name, this.DisplayName)));
            }

            return new IndexerLocation(operandValue, indicesValue, getMethod, setMethod); 
        }
 
 
        [DataContract]
        class IndexerLocation : Location 
        {
            [DataMember(EmitDefaultValue = false)]
            TOperand operand;
 
            [DataMember(EmitDefaultValue = false)]
            object[] indices; 
 
            [DataMember(EmitDefaultValue = false)]
            object[] parameters; 

            [DataMember(EmitDefaultValue = false)]
            MethodInfo getMethod;
 
            [DataMember(EmitDefaultValue = false)]
            MethodInfo setMethod; 
 
            public IndexerLocation(TOperand operand, object[] indices, MethodInfo getMethod, MethodInfo setMethod)
                : base() 
            {
                this.operand = operand;
                this.indices = indices;
                this.getMethod = getMethod; 
                this.setMethod = setMethod;
            } 
 
            public override TItem Value
            { 
                get
                {
                    Fx.Assert(this.operand != null, "operand must not be null");
                    Fx.Assert(this.indices != null, "indices must not be null"); 
                    if (this.getMethod == null)
                    { 
                        throw FxTrace.Exception.AsError(new InvalidOperationException(SR.SpecialMethodNotFound("get_Item", typeof(TOperand).Name))); 
                    }
                    return (TItem)this.getMethod.Invoke(this.operand, indices); 
                }
                set
                {
                    Fx.Assert(this.setMethod != null, "setMethod must not be null"); 
                    Fx.Assert(this.operand != null, "operand must not be null");
                    Fx.Assert(this.indices != null, "indices must not be null"); 
                    if (this.parameters == null) 
                    {
                        this.parameters = new object[this.indices.Length + 1]; 
                        for (int i = 0; i < this.indices.Length; i++)
                        {
                            parameters[i] = this.indices[i];
                        } 
                        parameters[parameters.Length - 1] = value;
                    } 
                    this.setMethod.Invoke(operand, parameters); 
                }
            } 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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IndexerReference.cs source code in C# .NET

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