Question

我正在开发电子表格类型POINT OF SALE（POS），其中将像在excel中一样输入项目，并通过向下，向左，向右箭头键在单元格之间导航。当程序运行时，我已经在datagrid中输入了10个空项目，就像excel空表一样，这就是为什么当用户在第一个单元格中输入一些值时，项目信息会从数据库中获取并更新Datagrid。此时，程序可以正常运行10个项目。

        <DataGridTextColumn Header="Code" Width="1*" Binding="{Binding Code, Mode=TwoWay}"/>
        <DataGridTextColumn Header="Name" Width="1*" Binding="{Binding Name, Mode=TwoWay}"/>
        <DataGridTextColumn Header="Description" Width="1*" Binding="{Binding Description, Mode=TwoWay}"/>
        <DataGridTextColumn Header="Quantity" Width="1*" Binding="{Binding Quantity, Mode=TwoWay}">
            <DataGridTextColumn.EditingElementStyle>
                <Style TargetType="{x:Type TextBox}">
                    <EventSetter Event="TextChanged" Handler="CellValueChanged" />
                </Style>
            </DataGridTextColumn.EditingElementStyle>
        </DataGridTextColumn>
        <DataGridTextColumn Header="Unit Price" Width="1*" Binding="{Binding UnitPrice, Mode=TwoWay}"/>
        <DataGridTextColumn Header="Sub-Total" Width="1*" Binding="{Binding SubTotal, Mode=TwoWay}"/>

事件：

private void Datagrid_CurrentCellChanged(object sender, EventArgs e)
        {
            DataGridCellInfo cell = Datagrid.SelectedCells[0];

            var generator = Datagrid.ItemContainerGenerator;
            int columnIndex = cell.Column.DisplayIndex;
            int rowIndex = generator.IndexFromContainer(generator.ContainerFromItem(cell.Item));


            if (header == "Code")
            {
                if (Datagrid.SelectedCells.Count > 0)
                {


                    //int counts = Datagrid.Items.Count;
                    //MessageBox.Show(counts.ToString() +" index "+rowIndex);
                    //MessageBox.Show("total counts: " + counts.ToString() + "Selected index " + rowIndex.ToString() + " column index: " + columnIndex);

                    var grid = sender as DataGrid;
                    var selected = grid.SelectedItems;
                    foreach (var items in selected)
                    {
                        if (items as Item != null)
                        {
                            string code = ((Item)Datagrid.Items[rowIndex]).Code;
                            Database database = new Database();
                            database.DBOpen();

                            SQLiteDataReader sQLiteDataReader = database.GetWhere(Database.TABLE_ITEMS, Database.CODE_ITEMS, code);
                            while (sQLiteDataReader.Read())
                            {
                                string name = sQLiteDataReader.GetString(2);
                                string desc = sQLiteDataReader.GetString(6);
                                string unitPrice = sQLiteDataReader.GetInt64(8).ToString();
                                string quantity = "1";
                                //string subTotal = (double.Parse(quantity) * double.Parse(unitPrice)).ToString();
                                //grossAmount = grossAmount + Double.Parse(subTotal);

                                Item item = new Item()
                                {
                                    Code = code,
                                    Name = name,
                                    Description = desc,
                                    Quantity = quantity,
                                    UnitPrice = unitPrice,
                                    //SubTotal = subTotal
                                };
                                ((Item)Datagrid.Items[rowIndex]).Code = code;
                                ((Item)Datagrid.Items[rowIndex]).Name = name;
                                ((Item)Datagrid.Items[rowIndex]).Description = desc;
                                ((Item)Datagrid.Items[rowIndex]).Quantity = quantity;
                                ((Item)Datagrid.Items[rowIndex]).UnitPrice = unitPrice;
                            }
                            database.DBClose();
                        }
                    }
                    }

正如您在事件代码（当前单元已更改）中所看到的那样，我正在从数据库中获取选定的单元格值及其相关信息，并使用((Item)Datagrid.Items[rowIndex]).Code = code;等进行更新。

问题是用户如何输入第11、12个条目？

注意：我已经在“事件”部分写了一些代码，

 if (rowIndex > 10)
        {
            var list = (IList<Item>)Datagrid.ItemsSource;

            list.Add(new Item());
        }

但是有例外。

Exception: Information for developers (use Text Visualizer to read this):
This exception was thrown because the generator for control 'System.Windows.Controls.DataGrid Items.Count:13' with name 'Datagrid'
收到了不一致的CollectionChanged事件序列具有Items集合的当前状态。下列检测到差异：累计计数12与实际计数13不同。[累计计数为（上次复位时的计数+ #Adds-#Remove自最后一次重置）。] 在索引10：生成器的项目“ Inventory_Control.Classes.Item”与实际项目“ Inventory_Control.Classes.Item”不同。在索引11：生成器的项目“ {NewItemPlaceholder}”与实际项目“ Inventory_Control.Classes.Item”不同。
One or more of the following sources may have raised the wrong events:
     System.Windows.Controls.ItemContainerGenerator
      System.Windows.Controls.ItemCollection
       System.Windows.Data.ListCollectionView
        System.Collections.Generic.List`1[[Inventory_Control.Classes.Item,
库存控制，版本= 1.0.0.0，文化=中性， PublicKeyToken = null]] （星标来源更可能是造成此问题的原因。）
The most common causes are (a) changing the collection or its Count without raising a corresponding event, and (b) raising an event
带有错误的索引或项目参数。
The exception's stack trace describes how the inconsistencies were detected, not how they occurred.  To get a more timely exception, set
附加属性“ PresentationTraceSources.TraceLevel”位于生成器将值设置为“高”并重新运行场景。一种方法是要运行类似于以下命令： System.Diagnostics.PresentationTraceSources.SetTraceLevel（myItemsControl.ItemContainerGenerator， System.Diagnostics.PresentationTraceLevel.High）从立即窗口。这会导致检测逻辑在每个CollectionChanged事件之后运行，因此会减慢检测速度。应用。

 void AddValues()
        {
            Datagrid.ItemsSource = null;

            List<Item> list = new List<Item>();
            list.Clear();

            for(int i = 0; i<10; i++)
            {
                string number = i.ToString();
                Item item = new Item()
                {
                };
                list.Add(item);
            }


            Datagrid.ItemsSource = list;
        }

到达最后一行索引时，将新Item添加到itemsource或Datagrid中

0 个答案: