How to paste the empty string while using cell selection in WPF DataGrid (SfDataGrid)?

public class CustomCopyPaste : GridCutCopyPaste
{
    public CustomCopyPaste(SfDataGrid sfgrid)
        : base(sfgrid)
    {
    }
 
    protected override void PasteToRow(object clipboardcontent, object selectedRecords)
    {
        if (dataGrid.SelectionUnit == GridSelectionUnit.Row)
            base.PasteToRow(clipboardcontent, selectedRecords);
        else
        {
            //Get the copied value.
            clipboardcontent = Regex.Split(clipboardcontent.ToString(), @"\t");
            var copyValue = (string[])clipboardcontent;
 
            int cellcount = copyValue.Count();
            var selectionContoller = this.dataGrid.SelectionController as GridCellSelectionController;
            var lastselectedindex = selectionContoller.CurrentCellManager.CurrentRowColumnIndex.ColumnIndex;
            //Get the PressedRowColumnIndex value using reflection from SelectionController.
            var PropertyInfo = (this.dataGrid.SelectionController as GridCellSelectionController).GetType().GetProperty("PressedRowColumnIndex", System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance);
            var pressedrowcolumnindex = PropertyInfo.GetValue(this.dataGrid.SelectionController);
            var pressedindex = ((RowColumnIndex)(pressedrowcolumnindex)).ColumnIndex;
            //Get the column index value that want to paste the first value.
            var pastecolumnindex = pressedindex < lastselectedindex ? pressedindex : lastselectedindex;
 
            int columnindex = 0;
            var columnStartIndex = this.dataGrid.ResolveToGridVisibleColumnIndex(pastecolumnindex);
            for (int i = columnStartIndex; i < cellcount + columnStartIndex; i++)
            {
                if (dataGrid.GridPasteOption.HasFlag(GridPasteOption.IncludeHiddenColumn))
                {
                    //Paste the copied value with hidden columns.
                    if (dataGrid.Columns.Count <= i)
                        break;
                    PasteToCell(selectedRecords, dataGrid.Columns[i], copyValue[columnindex]);
                    columnindex++;
                }
                else
                {
                    if (dataGrid.Columns.Count <= i)
                        break;
                    //Paste the copied value without hidden columns.
                    if (!dataGrid.Columns[i].IsHidden)
                    {
                        PasteToCell(selectedRecords, dataGrid.Columns[i], copyValue[columnindex]);
                        columnindex++;
                    }
                    else
                        cellcount++;
                }
            }
        }
    }
}