ExpressionLink.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / Orcas / SP / ndp / fx / src / DataEntity / System / Data / Common / CommandTrees / Internal / ExpressionLink.cs / 3 / ExpressionLink.cs
                        

                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner  [....], [....]
//--------------------------------------------------------------------- 
 
using System;
using System.Collections.Generic; 
using System.Data.Common;
using System.Diagnostics;
using System.Globalization;
using System.Data.Metadata.Edm; 
using System.Data.Common.CommandTrees;
 
namespace System.Data.Common.CommandTrees.Internal 
{
    internal delegate void ExpressionLinkConstraint(ExpressionLink link, DbExpression newValue); 

    internal class ExpressionLink
    {
        private string _name; 
        private DbCommandTree _tree;
        private DbExpression _expression; 
        private TypeUsage _expectedType; 

        ///  
        /// Creates a new ExpressionLink. The Expected Type and inital value are not set.
        /// 
        /// The name of the DbExpression property that this ExpressionLink implements
        /// The command tree that owns this ExpressionLink 
        internal ExpressionLink(string name, DbCommandTree commandTree)
        { 
            _name = name; 
            _tree = EntityUtil.CheckArgumentNull(commandTree, "commandTree");
        } 

        /// 
        /// Creates a new ExpressionLink with the specified initial value. The Expected Type of the ExpressionLink is fixed as the Type of the initial value
        ///  
        /// The name of the DbExpression property that this ExpressionLink implements
        /// The command tree that owns this ExpressionLink 
        /// An expression that provides the initial value of the ExpressionLink 
        internal ExpressionLink(string strName, DbCommandTree commandTree, DbExpression initialValue)
            : this(strName, commandTree) 
        {
            //
            // Attempt to set the DbExpression property to the specified initial value
            // 
            this.InitializeValue(initialValue);
 
            // 
            // If initialization was successful then fix the type of the initial value as the type to which subsequent expressions values must be promotable
            // 
            this.SetExpectedType(initialValue.ResultType);
        }

        ///  
        /// Creates a new ExpressionLink with the specified expected type.
        ///  
        /// The name of the DbExpression property that this ExpressionLink implements 
        /// The command tree that owns this ExpressionLink
        /// A description of the type to which the types of values assigned to this ExpressionLink must be promotable 
        internal ExpressionLink(string name, DbCommandTree commandTree, TypeUsage expectedType)
            : this(name, commandTree)
        {
            // 
            // Fix the specified type as the type to which future values must be promotable
            // 
            this.SetExpectedType(expectedType); 
        }
 
        /// 
        /// Creates a new ExpressionLink with the specified expected type and initial value. If the specified value is not promotable to the expected type an exception is thrown.
        /// 
        /// The name of the DbExpression property that this ExpressionLink implements 
        /// The command tree that owns this ExpressionLink
        /// A description of the type to which the types of values assigned to this ExpressionLink must be promotable 
        /// A DbExpression that provides the initial value of the ExpressionLink 
        /// If the Type of the inital value is not promotable to the expected type
        internal ExpressionLink(string name, DbCommandTree commandTree, TypeUsage expectedType, DbExpression initialValue) 
            : this(name, commandTree)
        {
            //
            // Fix the specified type as the type to which future values must be promotable 
            //
            this.SetExpectedType(expectedType); 
 
            //
            // Attempt to set the DbExpression property to the specified initial value 
            //
            this.InitializeValue(initialValue);
        }
 
        /// 
        /// Creates a new ExpressionLink with the specified expected primitive type and initial value. If the specified value is not promotable to the expected ModelType an exception is thrown. 
        ///  
        /// The name of the DbExpression property that this ExpressionLink implements
        /// The command tree that owns this ExpressionLink 
        /// The primitive type to which the types of values assigned to this ExpressionLink must be promotable
        /// A DbExpression that provides the initial value of the ExpressionLink
        /// If the Type of the inital value is not promotable to the expected primitive type
        internal ExpressionLink(string name, DbCommandTree commandTree, PrimitiveTypeKind expectedPrimitiveType, DbExpression initialValue) 
            : this(name, commandTree)
        { 
            // initialValue cannot be null 
            EntityUtil.CheckArgumentNull(initialValue, this.Name);
 
            //
            // Ensure initialValue is the expected primitive type
            //
            PrimitiveTypeKind valueTypeKind; 
            bool valueIsPrimitive = TypeHelpers.TryGetPrimitiveTypeKind(initialValue.ResultType, out valueTypeKind);
            if( !valueIsPrimitive || 
                valueTypeKind != expectedPrimitiveType) 
            {
                throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_ExpressionLink_TypeMismatch(Enum.GetName(typeof(PrimitiveTypeKind), expectedPrimitiveType), valueIsPrimitive ? Enum.GetName(typeof(PrimitiveTypeKind), valueTypeKind) : TypeHelpers.GetFullName(initialValue.ResultType)), this.Name); 
            }

            //
            // Fix the specified type as the type to which future values must be promotable 
            //
            this.SetExpectedType(initialValue.ResultType); 
 
            //
            // Attempt to set the DbExpression property to the specified initial value 
            //
            this.InitializeValue(initialValue);
        }
 

        internal string Name { get { return _name; } } 
 
        public DbExpression Expression
        { 
            get { return _expression; }
            set
            {
                // 
                // Verify that the expression satisifes the constraints of this ExpressionLink
                // 
                if (this.CheckValue(value)) 
                {
                    // Update the DbExpression property and inform the owner tree that it should be considered 'modified' 
                    this.UpdateValue(value);
                    _tree.SetModified();
                }
            } 
        }
 
        ///  
        /// Sets the DbExpression value of this ExpressionLink without instructing the owning command tree to consider itself 'modified'.
        /// Should only be used when setting the initial value of the ExpressionLink. 
        /// 
        /// 
        internal void InitializeValue(DbExpression initialValue)
        { 
            this.CheckValue(initialValue);
            this.UpdateValue(initialValue); 
        } 

        ///  
        /// Sets the type to which the types of values assigned to this ExpressionLink must be promotable.
        /// Can only be set once. Subsequent attempts to set the expected type will result in an exception.
        /// 
        /// A TypeUsage instance that describes the expected type 
        /// If the expected type has already been set
        internal void SetExpectedType(TypeUsage expectedType) 
        { 
            Debug.Assert(null == _expectedType, "ExpressionLink.SetExpectedType should only be called once");
            Debug.Assert(expectedType.IsReadOnly, "Editable type used as ExpressionLink expected type"); 
            _expectedType = expectedType;
        }

        internal event ExpressionLinkConstraint ValueChanging; 
#if EXPRESSIONLINK_FIRE_CHANGED
        internal event ExpressionLinkConstraint ValueChanged; 
#endif 

        private bool CheckValue(DbExpression newValue) 
        {
            //
            // Is the DbExpression null?
            // 
            EntityUtil.CheckArgumentNull(newValue, this.Name);
 
            if (object.ReferenceEquals(newValue, _expression)) 
            {
                return false; 
            }

            // Does the DbExpression belong to the expected command tree?
            if (!object.ReferenceEquals(_tree, newValue.CommandTree)) 
            {
                throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_General_TreeMismatch, this.Name); 
            } 

            // Is the Type of the new value promotable to the Type of the old value? 
            if (_expectedType != null)
            {
                if (!TypeSemantics.IsEquivalentOrPromotableTo(newValue.ResultType, _expectedType))
                { 
                    throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_ExpressionLink_TypeMismatch(
                            TypeHelpers.GetFullName(_expectedType), 
                            TypeHelpers.GetFullName(newValue.ResultType) 
                        ),
                        this.Name 
                    );
                }
            }
 
            // If the Type of the new value is NullType, throw if NullType is not allowed
            if (TypeSemantics.IsNullType(newValue.ResultType)) 
            { 
                throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_ExpressionLink_NullTypeInvalid(this.Name), this.Name);
            } 

            //
            // All invariant constraints have been satisfied, so raise the Changing event to allow dynamic constraints to be tested
            // 
            if (this.ValueChanging != null)
            { 
                this.ValueChanging(this, newValue); 
            }
 
            return true;
        }

        private void UpdateValue(DbExpression newValue) 
        {
            _expression = newValue; 
#if EXPRESSIONLINK_FIRECHANGED 
            if (this.ValueChanged != null)
            { 
                this.ValueChanged(this, newValue);
            }
#endif
        } 
    } // End of class ExpressionLink
} // End of namespace System.Data.Common.CommandTrees.Internal 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner  [....], [....]
//--------------------------------------------------------------------- 
 
using System;
using System.Collections.Generic; 
using System.Data.Common;
using System.Diagnostics;
using System.Globalization;
using System.Data.Metadata.Edm; 
using System.Data.Common.CommandTrees;
 
namespace System.Data.Common.CommandTrees.Internal 
{
    internal delegate void ExpressionLinkConstraint(ExpressionLink link, DbExpression newValue); 

    internal class ExpressionLink
    {
        private string _name; 
        private DbCommandTree _tree;
        private DbExpression _expression; 
        private TypeUsage _expectedType; 

        ///  
        /// Creates a new ExpressionLink. The Expected Type and inital value are not set.
        /// 
        /// The name of the DbExpression property that this ExpressionLink implements
        /// The command tree that owns this ExpressionLink 
        internal ExpressionLink(string name, DbCommandTree commandTree)
        { 
            _name = name; 
            _tree = EntityUtil.CheckArgumentNull(commandTree, "commandTree");
        } 

        /// 
        /// Creates a new ExpressionLink with the specified initial value. The Expected Type of the ExpressionLink is fixed as the Type of the initial value
        ///  
        /// The name of the DbExpression property that this ExpressionLink implements
        /// The command tree that owns this ExpressionLink 
        /// An expression that provides the initial value of the ExpressionLink 
        internal ExpressionLink(string strName, DbCommandTree commandTree, DbExpression initialValue)
            : this(strName, commandTree) 
        {
            //
            // Attempt to set the DbExpression property to the specified initial value
            // 
            this.InitializeValue(initialValue);
 
            // 
            // If initialization was successful then fix the type of the initial value as the type to which subsequent expressions values must be promotable
            // 
            this.SetExpectedType(initialValue.ResultType);
        }

        ///  
        /// Creates a new ExpressionLink with the specified expected type.
        ///  
        /// The name of the DbExpression property that this ExpressionLink implements 
        /// The command tree that owns this ExpressionLink
        /// A description of the type to which the types of values assigned to this ExpressionLink must be promotable 
        internal ExpressionLink(string name, DbCommandTree commandTree, TypeUsage expectedType)
            : this(name, commandTree)
        {
            // 
            // Fix the specified type as the type to which future values must be promotable
            // 
            this.SetExpectedType(expectedType); 
        }
 
        /// 
        /// Creates a new ExpressionLink with the specified expected type and initial value. If the specified value is not promotable to the expected type an exception is thrown.
        /// 
        /// The name of the DbExpression property that this ExpressionLink implements 
        /// The command tree that owns this ExpressionLink
        /// A description of the type to which the types of values assigned to this ExpressionLink must be promotable 
        /// A DbExpression that provides the initial value of the ExpressionLink 
        /// If the Type of the inital value is not promotable to the expected type
        internal ExpressionLink(string name, DbCommandTree commandTree, TypeUsage expectedType, DbExpression initialValue) 
            : this(name, commandTree)
        {
            //
            // Fix the specified type as the type to which future values must be promotable 
            //
            this.SetExpectedType(expectedType); 
 
            //
            // Attempt to set the DbExpression property to the specified initial value 
            //
            this.InitializeValue(initialValue);
        }
 
        /// 
        /// Creates a new ExpressionLink with the specified expected primitive type and initial value. If the specified value is not promotable to the expected ModelType an exception is thrown. 
        ///  
        /// The name of the DbExpression property that this ExpressionLink implements
        /// The command tree that owns this ExpressionLink 
        /// The primitive type to which the types of values assigned to this ExpressionLink must be promotable
        /// A DbExpression that provides the initial value of the ExpressionLink
        /// If the Type of the inital value is not promotable to the expected primitive type
        internal ExpressionLink(string name, DbCommandTree commandTree, PrimitiveTypeKind expectedPrimitiveType, DbExpression initialValue) 
            : this(name, commandTree)
        { 
            // initialValue cannot be null 
            EntityUtil.CheckArgumentNull(initialValue, this.Name);
 
            //
            // Ensure initialValue is the expected primitive type
            //
            PrimitiveTypeKind valueTypeKind; 
            bool valueIsPrimitive = TypeHelpers.TryGetPrimitiveTypeKind(initialValue.ResultType, out valueTypeKind);
            if( !valueIsPrimitive || 
                valueTypeKind != expectedPrimitiveType) 
            {
                throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_ExpressionLink_TypeMismatch(Enum.GetName(typeof(PrimitiveTypeKind), expectedPrimitiveType), valueIsPrimitive ? Enum.GetName(typeof(PrimitiveTypeKind), valueTypeKind) : TypeHelpers.GetFullName(initialValue.ResultType)), this.Name); 
            }

            //
            // Fix the specified type as the type to which future values must be promotable 
            //
            this.SetExpectedType(initialValue.ResultType); 
 
            //
            // Attempt to set the DbExpression property to the specified initial value 
            //
            this.InitializeValue(initialValue);
        }
 

        internal string Name { get { return _name; } } 
 
        public DbExpression Expression
        { 
            get { return _expression; }
            set
            {
                // 
                // Verify that the expression satisifes the constraints of this ExpressionLink
                // 
                if (this.CheckValue(value)) 
                {
                    // Update the DbExpression property and inform the owner tree that it should be considered 'modified' 
                    this.UpdateValue(value);
                    _tree.SetModified();
                }
            } 
        }
 
        ///  
        /// Sets the DbExpression value of this ExpressionLink without instructing the owning command tree to consider itself 'modified'.
        /// Should only be used when setting the initial value of the ExpressionLink. 
        /// 
        /// 
        internal void InitializeValue(DbExpression initialValue)
        { 
            this.CheckValue(initialValue);
            this.UpdateValue(initialValue); 
        } 

        ///  
        /// Sets the type to which the types of values assigned to this ExpressionLink must be promotable.
        /// Can only be set once. Subsequent attempts to set the expected type will result in an exception.
        /// 
        /// A TypeUsage instance that describes the expected type 
        /// If the expected type has already been set
        internal void SetExpectedType(TypeUsage expectedType) 
        { 
            Debug.Assert(null == _expectedType, "ExpressionLink.SetExpectedType should only be called once");
            Debug.Assert(expectedType.IsReadOnly, "Editable type used as ExpressionLink expected type"); 
            _expectedType = expectedType;
        }

        internal event ExpressionLinkConstraint ValueChanging; 
#if EXPRESSIONLINK_FIRE_CHANGED
        internal event ExpressionLinkConstraint ValueChanged; 
#endif 

        private bool CheckValue(DbExpression newValue) 
        {
            //
            // Is the DbExpression null?
            // 
            EntityUtil.CheckArgumentNull(newValue, this.Name);
 
            if (object.ReferenceEquals(newValue, _expression)) 
            {
                return false; 
            }

            // Does the DbExpression belong to the expected command tree?
            if (!object.ReferenceEquals(_tree, newValue.CommandTree)) 
            {
                throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_General_TreeMismatch, this.Name); 
            } 

            // Is the Type of the new value promotable to the Type of the old value? 
            if (_expectedType != null)
            {
                if (!TypeSemantics.IsEquivalentOrPromotableTo(newValue.ResultType, _expectedType))
                { 
                    throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_ExpressionLink_TypeMismatch(
                            TypeHelpers.GetFullName(_expectedType), 
                            TypeHelpers.GetFullName(newValue.ResultType) 
                        ),
                        this.Name 
                    );
                }
            }
 
            // If the Type of the new value is NullType, throw if NullType is not allowed
            if (TypeSemantics.IsNullType(newValue.ResultType)) 
            { 
                throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_ExpressionLink_NullTypeInvalid(this.Name), this.Name);
            } 

            //
            // All invariant constraints have been satisfied, so raise the Changing event to allow dynamic constraints to be tested
            // 
            if (this.ValueChanging != null)
            { 
                this.ValueChanging(this, newValue); 
            }
 
            return true;
        }

        private void UpdateValue(DbExpression newValue) 
        {
            _expression = newValue; 
#if EXPRESSIONLINK_FIRECHANGED 
            if (this.ValueChanged != null)
            { 
                this.ValueChanged(this, newValue);
            }
#endif
        } 
    } // End of class ExpressionLink
} // End of namespace System.Data.Common.CommandTrees.Internal 

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

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