DataGridState.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / WinForms / Managed / System / WinForms / DataGridState.cs / 1 / DataGridState.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

 
namespace System.Windows.Forms { 

    using System.Diagnostics; 

    using System;
    using System.Text;
    using System.Runtime.InteropServices; 
    using System.Windows.Forms;
    using System.ComponentModel; 
    using System.Drawing; 
    using Microsoft.Win32;
    using System.Security.Permissions; 

    /// 
    /// 
    ///      Encapsulates the state of a DataGrid that changes when the 
    ///      user navigates back and forth through ADO.NET data relations.
    ///  
    internal sealed class DataGridState : ICloneable { 
        // fields
        // 
        public object DataSource = null;
        public string DataMember = null;
        public CurrencyManager ListManager = null;
        public DataGridRow[] DataGridRows    = new DataGridRow[0]; 
        public DataGrid DataGrid;
        public int DataGridRowsLength = 0; 
        public GridColumnStylesCollection GridColumnStyles = null; 

        public int           FirstVisibleRow = 0; 
        public int           FirstVisibleCol = 0;

        public int           CurrentRow      = 0;
        public int           CurrentCol      = 0; 

        public DataGridRow   LinkingRow      = null; 
        AccessibleObject         parentRowAccessibleObject; 

        public DataGridState() { 
        }

        public DataGridState(DataGrid dataGrid) {
            PushState(dataGrid); 
        }
 
        internal AccessibleObject ParentRowAccessibleObject { 
            get {
                if (parentRowAccessibleObject == null) { 
                    parentRowAccessibleObject = new DataGridStateParentRowAccessibleObject(this);
                }
                return parentRowAccessibleObject;
            } 
        }
 
        // methods 
        //
 
        public object Clone() {
            DataGridState dgs = new DataGridState();
            dgs.DataGridRows = DataGridRows;
            dgs.DataSource = DataSource; 
            dgs.DataMember = DataMember;
            dgs.FirstVisibleRow = FirstVisibleRow; 
            dgs.FirstVisibleCol = FirstVisibleCol; 
            dgs.CurrentRow = CurrentRow;
            dgs.CurrentCol = CurrentCol; 
            dgs.GridColumnStyles = GridColumnStyles;
            dgs.ListManager = ListManager;
            dgs.DataGrid = DataGrid;
            return dgs; 
        }
 
        ///  
        /// 
        ///      Called by a DataGrid when it wishes to preserve its 
        ///      transient state in the current DataGridState object.
        /// 
        public void PushState(DataGrid dataGrid) {
            this.DataSource = dataGrid.DataSource; 
            this.DataMember = dataGrid.DataMember;
            this.DataGrid = dataGrid; 
            this.DataGridRows = dataGrid.DataGridRows; 
            this.DataGridRowsLength = dataGrid.DataGridRowsLength;
            this.FirstVisibleRow = dataGrid.firstVisibleRow; 
            this.FirstVisibleCol = dataGrid.firstVisibleCol;
            this.CurrentRow = dataGrid.currentRow;
            this.GridColumnStyles = new GridColumnStylesCollection(dataGrid.myGridTable);
 
            this.GridColumnStyles.Clear();
            foreach(DataGridColumnStyle style in dataGrid.myGridTable.GridColumnStyles) { 
                this.GridColumnStyles.Add(style); 
            }
 
            this.ListManager = dataGrid.ListManager;
            this.ListManager.ItemChanged += new ItemChangedEventHandler(DataSource_Changed);
            this.ListManager.MetaDataChanged += new EventHandler(DataSource_MetaDataChanged);
            this.CurrentCol = dataGrid.currentCol; 
        }
 
        // this is needed so that the parent rows will remove notification from the list 
        // when the datagridstate is no longer needed;
        public void RemoveChangeNotification() { 
            this.ListManager.ItemChanged -= new ItemChangedEventHandler(DataSource_Changed);
            this.ListManager.MetaDataChanged -= new EventHandler(DataSource_MetaDataChanged);
        }
 
        /// 
        ///  
        ///      Called by a grid when it wishes to match its transient 
        ///      state with the current DataGridState object.
        ///  
        public void PullState(DataGrid dataGrid, bool createColumn) {
            // dataGrid.DataSource = DataSource;
            // dataGrid.DataMember = DataMember;
            dataGrid.Set_ListManager(DataSource, DataMember, true, createColumn);   // true for forcing new listManager, 

            /* 
            if (DataSource.Table.ParentRelations.Count > 0) 
                dataGrid.PopulateColumns();
            */ 

            dataGrid.firstVisibleRow = FirstVisibleRow;
            dataGrid.firstVisibleCol = FirstVisibleCol;
            dataGrid.currentRow = CurrentRow; 
            dataGrid.currentCol = CurrentCol;
            dataGrid.SetDataGridRows(DataGridRows, DataGridRowsLength); 
        } 

        private void DataSource_Changed(object sender, ItemChangedEventArgs e) { 
            if (this.DataGrid != null && this.ListManager.Position == e.Index) {
                DataGrid.InvalidateParentRows();
                return;
            } 

            if (this.DataGrid != null) 
                DataGrid.ParentRowsDataChanged(); 
        }
 
        private void DataSource_MetaDataChanged(object sender, EventArgs e) {
            if (this.DataGrid != null)
                DataGrid.ParentRowsDataChanged();
        } 

 
        [ComVisible(true)] 
        internal class DataGridStateParentRowAccessibleObject : AccessibleObject {
            DataGridState owner = null; 

            public DataGridStateParentRowAccessibleObject(DataGridState owner) : base() {
                Debug.Assert(owner != null, "DataGridRowAccessibleObject must have a valid owner DataGridRow");
                this.owner = owner; 
            }
 
            public override Rectangle Bounds { 
                get {
                    DataGridParentRows dataGridParentRows = ((DataGridParentRows.DataGridParentRowsAccessibleObject)this.Parent).Owner; 
                    DataGrid g = owner.LinkingRow.DataGrid;
                    Rectangle r = dataGridParentRows.GetBoundsForDataGridStateAccesibility(owner);
                    r.Y += g.ParentRowsBounds.Y;
                    return g.RectangleToScreen(r); 
                }
            } 
 
            public override string Name {
                get { 
                    return SR.GetString(SR.AccDGParentRow);
                }
            }
 
            public override AccessibleObject Parent {
                [SecurityPermission(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)] 
                get { 
                    return owner.LinkingRow.DataGrid.ParentRowsAccessibleObject;
                } 
            }

            public override AccessibleRole Role {
                get { 
                    return AccessibleRole.ListItem;
                } 
            } 

            public override string Value { 
                [SecurityPermission(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]
                get {
                    StringBuilder sb = new StringBuilder();
 
                    CurrencyManager source = (CurrencyManager)owner.LinkingRow.DataGrid.BindingContext[owner.DataSource, owner.DataMember];
 
                    sb.Append(owner.ListManager.GetListName()); 
                    sb.Append(": ");
 
                    bool needComma = false;
                    foreach (DataGridColumnStyle col in owner.GridColumnStyles) {
                        if (needComma) {
                            sb.Append(", "); 
                        }
 
                        string colName = col.HeaderText; 
                        string cellValue = col.PropertyDescriptor.Converter.ConvertToString(col.PropertyDescriptor.GetValue(source.Current));
                        sb.Append(colName); 
                        sb.Append(": ");
                        sb.Append(cellValue);
                        needComma = true;
                    } 

                    return sb.ToString(); 
                } 
            }
 
            /// 
            /// 
            ///      Navigate to the next or previous grid entry.
            ///  
            [SecurityPermission(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]
            public override AccessibleObject Navigate(AccessibleNavigation navdir) { 
                DataGridParentRows.DataGridParentRowsAccessibleObject parentAcc = (DataGridParentRows.DataGridParentRowsAccessibleObject)Parent; 

                switch (navdir) { 
                    case AccessibleNavigation.Down:
                    case AccessibleNavigation.Right:
                    case AccessibleNavigation.Next:
                        return parentAcc.GetNext(this); 
                    case AccessibleNavigation.Up:
                    case AccessibleNavigation.Left: 
                    case AccessibleNavigation.Previous: 
                        return parentAcc.GetPrev(this);
                } 

                return null;

            } 
        }
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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DataGridState.cs source code in C# .NET

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