事件仅从第二次触发

Question

有一个文本框类型列'Qty'，在gridview中，只能接受数字。foll。代码工作良好，但只有从第二个输入。我只想在这里使用keydown

private void GridViewSale_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{     
  if (GridViewSale.CurrentCell.ColumnIndex == 4) //Allow only numbers for QTY column
    {
      TextBox Qty = e.Control as TextBox;
      Qty.KeyDown += new KeyEventHandler(Qty_KeyDown);
    }
}
void Qty_KeyDown(object sender, KeyEventArgs e)
{         
  if ((e.KeyValue >= 48 && e.KeyValue <= 57) || (e.KeyValue >= 96 && e.KeyValue <= 105)//Allows numerics
    e.SuppressKeyPress = false;
  else
    e.SuppressKeyPress = true;           
  }

1。我应该在其他地方调用事件处理程序，如form_load..对每个输入都有效?
2. 如果我必须禁用修饰符输入(SHIFT+1,SHIFT+2)，我应该如何在这里编写?

Answer 1

找到了这种行为的原因:任何keydown(char,num或symbol)第一次直接去' editingcontrolshow '方法而不是' keydown '。输入已经被取走了，所以问题来了。我解决了这个问题。解决方案。(用PreviewKeyDown &增加了CellBeginEdit，在单元格进入编辑模式之前检查键值:

private void GridViewSale_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
  {
    if (GridViewSale.CurrentCell.ColumnIndex == 4)//Allow only nums for QTY col.
          {
              TextBox Qty = e.Control as TextBox;
              Qty.KeyDown -= OnlyNums_KeyDown;
              Qty.KeyDown += OnlyNums_KeyDown;
          }
  }
private void GridViewSale_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
  {
     if ((e.KeyValue >= 48 && e.KeyValue <= 57) || (e.KeyValue >= 96 && e.KeyValue <= 105))
          {
              //Do Nothing
          }
          else
          {
              cancelEdit = true;
              GridViewSale.CellBeginEdit -= GridViewSale_CellBeginEdit;
              GridViewSale.CellBeginEdit += GridViewSale_CellBeginEdit;
          }
      }
private void GridViewSale_CellBeginEdit(object sender, DataGridViewCellCancelEventArgs e)
  {
      if (cancelEdit == true)
      {
          e.Cancel = true;
          cancelEdit = false;
      }
  } 

[我的第二个问题仍然没有答案]。