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在DataGridView中对组合框单元格进行选择是添加一个新行

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我正在学习如何在Visual Studio(Winforms)中使用datagridview并遇到此问题 .

当我运行程序,并单击第一列(包含名为Item的组合框列)并选择第一个行单元格并进行选择时,会在其下方自动添加一个我不想要的新行 .

我的代码:

// set values to combobox column cells in datagridview
DataGridViewComboBoxColumn cmbItems = (DataGridViewComboBoxColumn)GridSellProducts.Columns["Item"];

cmbItems.DataSource = productNames;
cmbItems.AutoComplete = true;

GridSellProducts.EditingControlShowing += new DataGridViewEditingControlShowingEventHandler(GridSellProducts_EditingControlShowing);

private void LastColumnComboSelectionChanged(object sender, EventArgs e)
{
      string itemValue = GridSellProducts.Rows[GridSellProducts.CurrentCell.RowIndex].Cells["Item"].FormattedValue.ToString();

      // get item price
      foreach (var item in itemListing)
      {
           if (item.name == itemValue)
           {
                    unitPrice = item.selling;
                    break;
           }
      }
}

private void GridSellProducts_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
     if (GridSellProducts.CurrentCell.ColumnIndex == 0 && e.Control is ComboBox)
     {
          ComboBox comboBox = e.Control as ComboBox;
          comboBox.SelectedIndexChanged += LastColumnComboSelectionChanged;
     }
}

我相信这是 string itemValue 总是返回“”的原因(行添加) . 我需要获取itemValue才能设置合适的价格 . 导致行添加的原因是什么?

1 回答

  • 2

    当您的用户可以向网格添加新行时,这是默认行为 . 插入的行被称为 NewRow ,等待新输入 . 要禁用此功能,您必须将 AllowUserToAddRows 设置为false,但这样您必须实现逻辑以添加新行 .

    还要注意以这种方式向内部控件添加事件:

    private void GridSellProducts_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
    {
         if (GridSellProducts.CurrentCell.ColumnIndex == 0 && e.Control is ComboBox)
         {
              ComboBox comboBox = e.Control as ComboBox;
              comboBox.SelectedIndexChanged += LastColumnComboSelectionChanged;
         }
    }
    

    起初它看起来没问题,但每次你点击组合框你都会添加新的事件处理程序,导致多次触发!正确的方式:

    private void GridSellProducts_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
    {
         if (GridSellProducts.CurrentCell.ColumnIndex == 0 && e.Control is ComboBox)
         {
              ComboBox comboBox = e.Control as ComboBox;
              comboBox.SelectedIndexChanged -= LastColumnComboSelectionChanged; //remove event if it was added before
              comboBox.SelectedIndexChanged += LastColumnComboSelectionChanged;
         }
    }
    

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