DataRowView.cs source code in C# .NET

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Code:

                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / Data / System / Data / DataRowView.cs / 4 / DataRowView.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// [....] 
// [....]
//----------------------------------------------------------------------------- 
 
namespace System.Data {
    using System.Diagnostics; 
    using System.ComponentModel;

#if WINFSInternalOnly
    internal 
#else
    public 
#endif 
    class DataRowView : ICustomTypeDescriptor, System.ComponentModel.IEditableObject, System.ComponentModel.IDataErrorInfo, System.ComponentModel.INotifyPropertyChanged {
 
        private readonly DataView dataView;
        private readonly DataRow _row;
        private bool delayBeginEdit;
 
        private static PropertyDescriptorCollection zeroPropertyDescriptorCollection = new PropertyDescriptorCollection(null);
 
        ///  
        /// When the PropertyChanged event happens, it must happen on the same DataRowView reference.
        /// This is so a generic event handler like Windows Presentation Foundation can redirect as appropriate. 
        /// Having DataView.Equals is not sufficient for WPF, because two different instances may be equal but not equivalent.
        /// For DataRowView, if two instances are equal then they are equivalent.
        /// 
        private System.ComponentModel.PropertyChangedEventHandler  onPropertyChanged; 

        internal DataRowView(DataView dataView, DataRow row) 
        { 
            this.dataView = dataView;
            this._row = row; 
        }

        /// 
        /// Checks for same reference instead of equivalent  or . 
        ///
        /// Necessary for ListChanged event handlers to use data structures that use the default to 
        ///  instead of  
        /// to understand if they need to add a  event handler.
        ///  
        /// 
        public override bool Equals(object other) {
            return Object.ReferenceEquals(this, other);
        } 

        /// Hashcode of  
        public override Int32 GetHashCode() { 
            // Everett compatability, must return hashcode for DataRow
            // this does prevent using this object in collections like Hashtable 
            // which use the hashcode as an immutable value to identify this object
            // user could/should have used the DataRow property instead of the hashcode
            return Row.GetHashCode();
        } 

        public DataView DataView { 
            get { 
                return dataView;
            } 
        }

        internal int ObjectID {
            get { return _row.ObjectID; } 
        }
 
        /// Gets or sets a value in specified column. 
        /// Specified column index.
        /// Uses either  or  to access  
        ///  when setting a value.
        /// 
        public object this[int ndx] {
            get { 
                return Row[ndx, RowVersionDefault];
            } 
            set { 
                if (!dataView.AllowEdit && !IsNew) {
                    throw ExceptionBuilder.CanNotEdit(); 
                }
                SetColumnValue(dataView.Table.Columns[ndx], value);
            }
        } 

        /// Gets the specified column value or related child view or sets a value in specified column. 
        /// Specified column or relation name when getting.  Specified column name when setting. 
        ///  when  is ambigous.
        /// Unmatched  when getting a value. 
        /// Unmatched  when setting a value.
        ///  when setting a value.
        public object this[string property] {
            get { 
                DataColumn column = dataView.Table.Columns[property];
                if (null != column) { 
                    return Row[column, RowVersionDefault]; 
                }
                else if (dataView.Table.DataSet != null && dataView.Table.DataSet.Relations.Contains(property)) { 
                    return CreateChildView(property);
                }
                throw ExceptionBuilder.PropertyNotFound(property, dataView.Table.TableName);
            } 
            set {
                DataColumn column = dataView.Table.Columns[property]; 
                if (null == column) { 
                    throw ExceptionBuilder.SetFailed(property);
                } 
                if (!dataView.AllowEdit && !IsNew) {
                    throw ExceptionBuilder.CanNotEdit();
                }
                SetColumnValue(column, value); 
            }
        } 
 
        // IDataErrorInfo stuff
        string System.ComponentModel.IDataErrorInfo.this[string colName] { 
            get {
                return Row.GetColumnError(colName);
            }
        } 

        string System.ComponentModel.IDataErrorInfo.Error { 
            get { 
                return Row.RowError;
            } 
        }

        /// 
        /// Gets the current version description of the  
        /// in relation to 
        ///  
        /// Either  or  
        public DataRowVersion RowVersion {
            get { 
                return (RowVersionDefault & ~DataRowVersion.Proposed);
            }
        }
 
        /// Either  or 
        private DataRowVersion RowVersionDefault { 
            get { 
                return Row.GetDefaultRowVersion(dataView.RowStateFilter);
            } 
        }

        internal int GetRecord() {
            return Row.GetRecordFromVersion(RowVersionDefault); 
        }
 
        internal object GetColumnValue(DataColumn column) { 
            return Row[column, RowVersionDefault];
        } 

        internal void SetColumnValue(DataColumn column, object value) {
            if (delayBeginEdit) {
                delayBeginEdit = false; 
                Row.BeginEdit();
            } 
            if (DataRowVersion.Original == RowVersionDefault) { 
                throw ExceptionBuilder.SetFailed(column.ColumnName);
            } 
            Row[column] = value;
        }

        ///  
        /// Returns a 
        /// for the child  
        /// with the specified . 
        /// 
        /// Specified . 
        /// null or mismatch between  and .
        public DataView CreateChildView(DataRelation relation) {
            if (relation == null || relation.ParentKey.Table != DataView.Table) {
                throw ExceptionBuilder.CreateChildView(); 
            }
            int record = GetRecord(); 
            object[] values = relation.ParentKey.GetKeyValues(record); 
            RelatedView childView = new RelatedView(relation.ChildColumnsReference, values);
            childView.SetIndex("", DataViewRowState.CurrentRows, null); // finish construction via RelatedView.SetIndex 
            childView.SetDataViewManager(DataView.DataViewManager);
            return childView;
        }
 
        /// 
        /// Specified  name. 
        /// Unmatched . 
        public DataView CreateChildView(string relationName) {
            return CreateChildView(DataView.Table.ChildRelations[relationName]); 
        }

        public DataRow Row {
            get { 
                return _row;
            } 
        } 

        public void BeginEdit() { 
            delayBeginEdit = true;
        }

        public void CancelEdit() { 
            DataRow tmpRow = Row;
            if (IsNew) { 
                dataView.FinishAddNew(false); 
            }
            else { 
                tmpRow.CancelEdit();
            }
            delayBeginEdit = false;
        } 

        public void EndEdit() { 
            if (IsNew) { 
                dataView.FinishAddNew(true);
            } 
            else {
                Row.EndEdit();
            }
            delayBeginEdit = false; 
        }
 
        public bool IsNew { 
            get {
                return (_row == dataView.addNewRow); 
            }
        }

        public bool IsEdit { 
            get {
                return ( 
                    Row.HasVersion(DataRowVersion.Proposed) ||  // It was edited or 
                    delayBeginEdit);                            // DataRowView.BegingEdit() was called, but not edited yet.
            } 
        }

        public void Delete() {
            dataView.Delete(Row); 
        }
 
        #region ICustomTypeDescriptor 

        AttributeCollection ICustomTypeDescriptor.GetAttributes() { 
            return new AttributeCollection((Attribute[])null);
        }

        string ICustomTypeDescriptor.GetClassName() { 
            return null;
        } 
 
        string ICustomTypeDescriptor.GetComponentName() {
            return null; 
        }

        TypeConverter ICustomTypeDescriptor.GetConverter() {
            return null; 
        }
 
        EventDescriptor ICustomTypeDescriptor.GetDefaultEvent() { 
            return null;
        } 

        PropertyDescriptor ICustomTypeDescriptor.GetDefaultProperty() {
            return null;
        } 

        object ICustomTypeDescriptor.GetEditor(Type editorBaseType) { 
            return null; 
        }
 
        EventDescriptorCollection ICustomTypeDescriptor.GetEvents() {
            return new EventDescriptorCollection(null);
        }
 
        EventDescriptorCollection ICustomTypeDescriptor.GetEvents(Attribute[] attributes) {
            return new EventDescriptorCollection(null); 
        } 

        PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties() { 
            return((ICustomTypeDescriptor)this).GetProperties(null);
        }

        PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties(Attribute[] attributes) { 
            return (dataView.Table != null ? dataView.Table.GetPropertyDescriptorCollection(attributes) : zeroPropertyDescriptorCollection);
        } 
 
        object ICustomTypeDescriptor.GetPropertyOwner(PropertyDescriptor pd) {
            return this; 
        }

        #endregion
 
        public event PropertyChangedEventHandler PropertyChanged {
            add { 
                onPropertyChanged += value; 
            }
            remove { 
                onPropertyChanged -= value;
            }

        } 

        internal void RaisePropertyChangedEvent (string propName){ 
            // Do not try catch, we would mask users bugs. if they throw we would catch 
            if (onPropertyChanged != null) {
                onPropertyChanged (this, new PropertyChangedEventArgs(propName)); 
            }
        }
    }
} 

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

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