wpf controls - WPF datagrid pasting

Question

I'm having trouble pasting from a csv into the wpf datagrid - I have followed the suggestions here

http://blogs.msdn.com/b/vinsibal/archive/2008/09/25/pasting-content-to-new-rows-on-the-wpf-datagrid.aspx

and the code exectues with no problem - however, it seems that all the new rows are created but only the first row gets populated with data. The data seems to be constantly overwritten so that the last item that is in the clipboard data is populated in the first row and all other rows are blank. I know this must be an index issue or something but I cannot track it down.

Also when I have a look at the objects in the grid's bindable collection none of them have any data in. Is there something in the OnPastingCellClipboardContent of the column that is going wrong (data conversion perhaps)?

Any ideas (see the code below)

protected virtual void OnExecutedPaste(object sender, ExecutedRoutedEventArgs args)
    {
        // parse the clipboard data
        List<string[]> rowData = ClipboardHelper.ParseClipboardData();
        bool hasAddedNewRow = false;

        // call OnPastingCellClipboardContent for each cell
        int minRowIndex = Math.Max(Items.IndexOf(CurrentItem), 0);
        int maxRowIndex = Items.Count - 1;
        int minColumnDisplayIndex = (SelectionUnit != DataGridSelectionUnit.FullRow) ? Columns.IndexOf(CurrentColumn) : 0;
        int maxColumnDisplayIndex = Columns.Count - 1;

        int rowDataIndex = 0;
        for (int i = minRowIndex; i <= maxRowIndex && rowDataIndex < rowData.Count; i++, rowDataIndex++)
        {
            if (CanUserAddRows && i == maxRowIndex)
            {
                // add a new row to be pasted to
                ICollectionView cv = CollectionViewSource.GetDefaultView(Items);
                IEditableCollectionView iecv = cv as IEditableCollectionView;
                if (iecv != null)
                {
                    hasAddedNewRow = true;
                    iecv.AddNew();
                    if (rowDataIndex + 1 < rowData.Count)
                    {
                        // still has more items to paste, update the maxRowIndex
                        maxRowIndex = Items.Count - 1;
                    }
                }
            }
            else if (i == maxRowIndex)
            {
                continue;
            }

            int columnDataIndex = 0;
            for (int j = minColumnDisplayIndex; j < maxColumnDisplayIndex && columnDataIndex < rowData[rowDataIndex].Length; j++, columnDataIndex++)
            {
                DataGridColumn column = ColumnFromDisplayIndex(j);
                column.OnPastingCellClipboardContent(Items[i], rowData[rowDataIndex][columnDataIndex]);
            }
        }

}

Answer 1

Thanks,

The post is very good by Vincent but KlausG Added some corrections in it that should also be considered to work with FrameWork 4.0. Very important

Original Web Site post from Vincent: http://blogs.msdn.com/b/vinsibal/archive/2008/09/25/pasting-content-to-new-rows-on-the-wpf-datagrid.aspx

Note: If you can't add row ensure that you have a default constructor for your item.

Updated 2018-03-06 (to support DataGrid with columns re-ordered by user)

Updated 2020-12-03 (according to Cesar Morigaki solution-correction and message from Antonio Rodríguez) Thanks to both!!!

Usage

<myControl:CustomDataGrid ...

CustomDataGrid

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace HQ.Wpf.Util.MyControl
{
    public class CustomDataGrid : DataGrid
    {
        public event ExecutedRoutedEventHandler ExecutePasteEvent;
        public event CanExecuteRoutedEventHandler CanExecutePasteEvent;

        // ******************************************************************
        static CustomDataGrid()
        {
            CommandManager.RegisterClassCommandBinding(
                typeof(CustomDataGrid),
                new CommandBinding(ApplicationCommands.Paste,
                    new ExecutedRoutedEventHandler(OnExecutedPasteInternal),
                    new CanExecuteRoutedEventHandler(OnCanExecutePasteInternal)));
        }

        // ******************************************************************
        #region Clipboard Paste

        // ******************************************************************
        private static void OnCanExecutePasteInternal(object target, CanExecuteRoutedEventArgs args)
        {
            ((CustomDataGrid)target).OnCanExecutePaste(target, args);
        }

        // ******************************************************************
        /// <summary>
        /// This virtual method is called when ApplicationCommands.Paste command query its state.
        /// </summary>
        /// <param name="args"></param>
        protected virtual void OnCanExecutePaste(object target, CanExecuteRoutedEventArgs args)
        {
            if (CanExecutePasteEvent != null)
            {
                CanExecutePasteEvent(target, args);
                if (args.Handled)
                {
                    return;
                }
            }

            args.CanExecute = CurrentCell != null;
            args.Handled = true;
        }

        // ******************************************************************
        private static void OnExecutedPasteInternal(object target, ExecutedRoutedEventArgs args)
        {
            ((CustomDataGrid)target).OnExecutedPaste(target, args);
        }

        // ******************************************************************
        /// <summary>
        /// This virtual method is called when ApplicationCommands.Paste command is executed.
        /// </summary>
        /// <param name="target"></param>
        /// <param name="args"></param>
        protected virtual void OnExecutedPaste(object target, ExecutedRoutedEventArgs args)
        {
            if (ExecutePasteEvent != null)
            {
                ExecutePasteEvent(target, args);
                if (args.Handled)
                {
                    return;
                }
            }

            // parse the clipboard data            [row][column]
            List<string[]> clipboardData = HQ.Util.General.Clipboard.ClipboardHelper2.ParseClipboardData();

            bool hasAddedNewRow = false;

            Debug.Print(">>> DataGrid Paste: >>>");
#if DEBUG
            StringBuilder sb = new StringBuilder();
#endif 
            int minRowIndex = Items.IndexOf(CurrentItem);
            int maxRowIndex = Items.Count - 1;
            int startIndexOfDisplayCol = (SelectionUnit != DataGridSelectionUnit.FullRow) ? CurrentColumn.DisplayIndex : 0;
            int clipboardRowIndex = 0;
            for (int i = minRowIndex; i <= maxRowIndex && clipboardRowIndex < clipboardData.Count; i++, clipboardRowIndex++)
            {
                if (i < this.Items.Count)
                {
                    CurrentItem = Items[i];

                    BeginEditCommand.Execute(null, this);

                    int clipboardColumnIndex = 0;
                    for (int j = startIndexOfDisplayCol; clipboardColumnIndex < clipboardData[clipboardRowIndex].Length; j++, clipboardColumnIndex++)
                    {
                        // DataGridColumn column = ColumnFromDisplayIndex(j);
                        DataGridColumn column = null;
                        foreach (DataGridColumn columnIter in this.Columns)
                        {
                            if (columnIter.DisplayIndex == j)
                            {
                                column = columnIter;
                                break;
                            }
                        }

                        column?.OnPastingCellClipboardContent(Items[i], clipboardData[clipboardRowIndex][clipboardColumnIndex]);

#if DEBUG
                        sb.AppendFormat("{0,-10}", clipboardData[clipboardRowIndex][clipboardColumnIndex]);
                        sb.Append(" - ");
#endif
                    }

                    CommitEditCommand.Execute(this, this);
                    if (i == maxRowIndex)
                    {
                        maxRowIndex++;
                        hasAddedNewRow = true;
                    }
                }

                Debug.Print(sb.ToString());
#if DEBUG
                sb.Clear();
#endif
            }

            // update selection
            if (hasAddedNewRow)
            {
                UnselectAll();
                UnselectAllCells();

                CurrentItem = Items[minRowIndex];

                if (SelectionUnit == DataGridSelectionUnit.FullRow)
                {
                    SelectedItem = Items[minRowIndex];
                }
                else if (SelectionUnit == DataGridSelectionUnit.CellOrRowHeader ||
                         SelectionUnit == DataGridSelectionUnit.Cell)
                {
                    SelectedCells.Add(new DataGridCellInfo(Items[minRowIndex], Columns[startIndexOfDisplayCol]));

                }
            }
        }

        // ******************************************************************
        /// <summary>
        ///     Whether the end-user can add new rows to the ItemsSource.
        /// </summary>
        public bool CanUserPasteToNewRows
        {
            get { return (bool)GetValue(CanUserPasteToNewRowsProperty); }
            set { SetValue(CanUserPasteToNewRowsProperty, value); }
        }

        // ******************************************************************
        /// <summary>
        ///     DependencyProperty for CanUserAddRows.
        /// </summary>
        public static readonly DependencyProperty CanUserPasteToNewRowsProperty =
            DependencyProperty.Register("CanUserPasteToNewRows",
                                        typeof(bool), typeof(CustomDataGrid),
                                        new FrameworkPropertyMetadata(true, null, null));

        // ******************************************************************
        #endregion Clipboard Paste

        private void SetGridToSupportManyEditEitherWhenValidationErrorExists()
        {
            this.Items.CurrentChanged += Items_CurrentChanged;


            //Type DatagridType = this.GetType().BaseType;
            //PropertyInfo HasCellValidationProperty = DatagridType.GetProperty("HasCellValidationError", BindingFlags.NonPublic | BindingFlags.Instance);
            //HasCellValidationProperty.
        }

        void Items_CurrentChanged(object sender, EventArgs e)
        {
            //this.Items[0].
            //throw new NotImplementedException();
        }

        // ******************************************************************
        private void SetGridWritable()
        {
            Type DatagridType = this.GetType().BaseType;
            PropertyInfo HasCellValidationProperty = DatagridType.GetProperty("HasCellValidationError", BindingFlags.NonPublic | BindingFlags.Instance);
            if (HasCellValidationProperty != null)
            {
                HasCellValidationProperty.SetValue(this, false, null);
            }
        }

        // ******************************************************************
        public void SetGridWritableEx()
        {
            BindingFlags bindingFlags = BindingFlags.FlattenHierarchy | BindingFlags.NonPublic | BindingFlags.Instance;
            PropertyInfo cellErrorInfo = this.GetType().BaseType.GetProperty("HasCellValidationError", bindingFlags);
            PropertyInfo rowErrorInfo = this.GetType().BaseType.GetProperty("HasRowValidationError", bindingFlags);
            cellErrorInfo.SetValue(this, false, null);
            rowErrorInfo.SetValue(this, false, null);
        }

        // ******************************************************************
    }
}

Also: Clipboard Helper:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.Windows;
using System.IO;

namespace HQ.Util.General.Clipboard
{
    public static class ClipboardHelper
    {
        public delegate string[] ParseFormat(string value);

        public static List<string[]> ParseClipboardData()
        {
            List<string[]> clipboardData = null;
            object clipboardRawData = null;
            ParseFormat parseFormat = null;

            // get the data and set the parsing method based on the format
            // currently works with CSV and Text DataFormats            
            IDataObject dataObj = System.Windows.Clipboard.GetDataObject();
            if ((clipboardRawData = dataObj.GetData(DataFormats.CommaSeparatedValue)) != null)
            {
                parseFormat = ParseCsvFormat;
            }
            else if((clipboardRawData = dataObj.GetData(DataFormats.Text)) != null)
            {
                parseFormat = ParseTextFormat;
            }

            if (parseFormat != null)
            {
                string rawDataStr = clipboardRawData as string;
                
                if (rawDataStr == null && clipboardRawData is MemoryStream)
                {
                    // cannot convert to a string so try a MemoryStream
                    MemoryStream ms = clipboardRawData as MemoryStream;
                    StreamReader sr = new StreamReader(ms);
                    rawDataStr = sr.ReadToEnd();
                }
                Debug.Assert(rawDataStr != null, string.Format("clipboardRawData: {0}, could not be converted to a string or memorystream.", clipboardRawData));

                string[] rows = rawDataStr.Split(new string[] { "
" }, StringSplitOptions.RemoveEmptyEntries);
                if (rows != null && rows.Length > 0)
                {
                    clipboardData = new L