FieldDescriptor.cs source code in C# .NET

                        Code:
                         / Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / Orcas / SP / ndp / fx / src / DataEntity / System / Data / Objects / FieldDescriptor.cs / 3 / FieldDescriptor.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 
using System;
using System.Collections; 
using System.Collections.Generic;
using System.ComponentModel;
using System.Data.Common;
using System.Data.Objects.DataClasses; 
using System.Data.Metadata.Edm;
 
namespace System.Data.Objects 
{
    internal sealed class FieldDescriptor : PropertyDescriptor 
    {
        private readonly EdmProperty _property;
        private readonly Type _fieldType;
        private readonly Type _componentType; 
        private readonly bool _isReadOnly;
 
        ///  
        /// Construct a new instance of the FieldDescriptor class that describes a property
        /// on components of the supplied type. 
        /// 
        /// Type of object whose property is described by this FieldDescriptor.
        /// 
        /// True if property value on component can be modified; otherwise false. 
        /// 
        ///  
        /// EdmProperty that describes the property on the component. 
        /// 
        internal FieldDescriptor(Type componentType, bool isReadOnly, EdmProperty property) 
            : base(property.Name, null)
        {
            _componentType = componentType;
            _property = property; 
            _isReadOnly = isReadOnly;
            _fieldType = DetermineClrType(_property.TypeUsage); 
            System.Diagnostics.Debug.Assert(_fieldType != null, "FieldDescriptor's CLR type has unexpected value of null."); 
        }
 
        /// 
        /// Determine a CLR Type to use a property descriptro form an EDM TypeUsage
        /// 
        /// The EDM TypeUsage containing metadata about the type 
        /// A CLR type that represents that EDM type
        private Type DetermineClrType(TypeUsage typeUsage) 
        { 
            Type result = null;
            EdmType edmType = typeUsage.EdmType; 

            switch (edmType.BuiltInTypeKind)
            {
                case BuiltInTypeKind.EntityType: 
                case BuiltInTypeKind.ComplexType:
                    result = edmType.ClrType; 
                    break; 

                case BuiltInTypeKind.RefType: 
                    result = typeof(EntityKey);
                    break;

                case BuiltInTypeKind.CollectionType: 
                    TypeUsage elementTypeUse = ((CollectionType)edmType).TypeUsage;
                    result = DetermineClrType(elementTypeUse); 
                    result = typeof(IEnumerable<>).MakeGenericType(result); 
                    break;
 
                case BuiltInTypeKind.PrimitiveType:
                    result = edmType.ClrType;
                    Facet nullable;
                    if (result.IsValueType && 
                        typeUsage.Facets.TryGetValue(DbProviderManifest.NullableFacetName, false, out nullable) &&
                        ((bool)nullable.Value)) 
                    { 
                        result = typeof(Nullable<>).MakeGenericType(result);
                    } 
                    break;

                case BuiltInTypeKind.RowType:
                    result = typeof(IDataRecord); 
                    break;
 
                default: 
                    throw EntityUtil.UnexpectedMetadataType(edmType);
            } 

            return result;
        }
 
        /// 
        /// Get  instance associated with this field descriptor. 
        ///  
        /// 
        /// The  instance associated with this field descriptor, 
        /// or null if there is no EDM property association.
        /// 
        internal EdmProperty EdmProperty
        { 
            get { return _property; }
        } 
 
        public override Type ComponentType
        { 
            get { return _componentType; }
        }
        public override bool IsReadOnly
        { 
            get { return _isReadOnly; }
        } 
        public override Type PropertyType 
        {
            get { return _fieldType; } 
        }
        public override bool CanResetValue(object component)
        {
            return false; 
        }
 
        public override object GetValue(object component) 
        {
            EntityUtil.CheckArgumentNull(component, "component"); 

            if (!_componentType.IsAssignableFrom(component.GetType()))
            {
                throw EntityUtil.IncompatibleArgument(); 
            }
 
            object propertyValue; 

            if (component is IEntityWithChangeTracker) //POCO will relax this requirement. 
            {
                propertyValue = LightweightCodeGenerator.GetValue(_property, component);
            }
            else 
            {
                DbDataRecord dbDataRecord = component as DbDataRecord; 
                if (dbDataRecord != null) 
                {
                    propertyValue = (dbDataRecord.GetValue(dbDataRecord.GetOrdinal(_property.Name))); 
                }
                else
                {
                    throw EntityUtil.NotSupported(); 
                }
            } 
 
            return propertyValue;
        } 
        public override void ResetValue(object component)
        {
            throw EntityUtil.NotSupported();
        } 

        public override void SetValue(object component, object value) 
        { 
            EntityUtil.CheckArgumentNull(component, "component");
            if (!_componentType.IsAssignableFrom(component.GetType())) 
            {
                throw EntityUtil.IncompatibleArgument();
            }
            if (!_isReadOnly && component is IEntityWithChangeTracker) //POCO will relax this requirement 
            {
                LightweightCodeGenerator.SetValue(_property, component, value); 
            } // if not entity it must be readonly 
            else
            { 
                throw EntityUtil.WriteOperationNotAllowedOnReadOnlyBindingList();
            }
        }
        public override bool ShouldSerializeValue(object component) 
        {
            return false; 
        } 
        public override bool IsBrowsable
        { 
            get { return true; }
        }
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner       [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 
using System;
using System.Collections; 
using System.Collections.Generic;
using System.ComponentModel;
using System.Data.Common;
using System.Data.Objects.DataClasses; 
using System.Data.Metadata.Edm;
 
namespace System.Data.Objects 
{
    internal sealed class FieldDescriptor : PropertyDescriptor 
    {
        private readonly EdmProperty _property;
        private readonly Type _fieldType;
        private readonly Type _componentType; 
        private readonly bool _isReadOnly;
 
        ///  
        /// Construct a new instance of the FieldDescriptor class that describes a property
        /// on components of the supplied type. 
        /// 
        /// Type of object whose property is described by this FieldDescriptor.
        /// 
        /// True if property value on component can be modified; otherwise false. 
        /// 
        ///  
        /// EdmProperty that describes the property on the component. 
        /// 
        internal FieldDescriptor(Type componentType, bool isReadOnly, EdmProperty property) 
            : base(property.Name, null)
        {
            _componentType = componentType;
            _property = property; 
            _isReadOnly = isReadOnly;
            _fieldType = DetermineClrType(_property.TypeUsage); 
            System.Diagnostics.Debug.Assert(_fieldType != null, "FieldDescriptor's CLR type has unexpected value of null."); 
        }
 
        /// 
        /// Determine a CLR Type to use a property descriptro form an EDM TypeUsage
        /// 
        /// The EDM TypeUsage containing metadata about the type 
        /// A CLR type that represents that EDM type
        private Type DetermineClrType(TypeUsage typeUsage) 
        { 
            Type result = null;
            EdmType edmType = typeUsage.EdmType; 

            switch (edmType.BuiltInTypeKind)
            {
                case BuiltInTypeKind.EntityType: 
                case BuiltInTypeKind.ComplexType:
                    result = edmType.ClrType; 
                    break; 

                case BuiltInTypeKind.RefType: 
                    result = typeof(EntityKey);
                    break;

                case BuiltInTypeKind.CollectionType: 
                    TypeUsage elementTypeUse = ((CollectionType)edmType).TypeUsage;
                    result = DetermineClrType(elementTypeUse); 
                    result = typeof(IEnumerable<>).MakeGenericType(result); 
                    break;
 
                case BuiltInTypeKind.PrimitiveType:
                    result = edmType.ClrType;
                    Facet nullable;
                    if (result.IsValueType && 
                        typeUsage.Facets.TryGetValue(DbProviderManifest.NullableFacetName, false, out nullable) &&
                        ((bool)nullable.Value)) 
                    { 
                        result = typeof(Nullable<>).MakeGenericType(result);
                    } 
                    break;

                case BuiltInTypeKind.RowType:
                    result = typeof(IDataRecord); 
                    break;
 
                default: 
                    throw EntityUtil.UnexpectedMetadataType(edmType);
            } 

            return result;
        }
 
        /// 
        /// Get  instance associated with this field descriptor. 
        ///  
        /// 
        /// The  instance associated with this field descriptor, 
        /// or null if there is no EDM property association.
        /// 
        internal EdmProperty EdmProperty
        { 
            get { return _property; }
        } 
 
        public override Type ComponentType
        { 
            get { return _componentType; }
        }
        public override bool IsReadOnly
        { 
            get { return _isReadOnly; }
        } 
        public override Type PropertyType 
        {
            get { return _fieldType; } 
        }
        public override bool CanResetValue(object component)
        {
            return false; 
        }
 
        public override object GetValue(object component) 
        {
            EntityUtil.CheckArgumentNull(component, "component"); 

            if (!_componentType.IsAssignableFrom(component.GetType()))
            {
                throw EntityUtil.IncompatibleArgument(); 
            }
 
            object propertyValue; 

            if (component is IEntityWithChangeTracker) //POCO will relax this requirement. 
            {
                propertyValue = LightweightCodeGenerator.GetValue(_property, component);
            }
            else 
            {
                DbDataRecord dbDataRecord = component as DbDataRecord; 
                if (dbDataRecord != null) 
                {
                    propertyValue = (dbDataRecord.GetValue(dbDataRecord.GetOrdinal(_property.Name))); 
                }
                else
                {
                    throw EntityUtil.NotSupported(); 
                }
            } 
 
            return propertyValue;
        } 
        public override void ResetValue(object component)
        {
            throw EntityUtil.NotSupported();
        } 

        public override void SetValue(object component, object value) 
        { 
            EntityUtil.CheckArgumentNull(component, "component");
            if (!_componentType.IsAssignableFrom(component.GetType())) 
            {
                throw EntityUtil.IncompatibleArgument();
            }
            if (!_isReadOnly && component is IEntityWithChangeTracker) //POCO will relax this requirement 
            {
                LightweightCodeGenerator.SetValue(_property, component, value); 
            } // if not entity it must be readonly 
            else
            { 
                throw EntityUtil.WriteOperationNotAllowedOnReadOnlyBindingList();
            }
        }
        public override bool ShouldSerializeValue(object component) 
        {
            return false; 
        } 
        public override bool IsBrowsable
        { 
            get { return true; }
        }
    }
} 

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

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