datatable.GetChanges（）始终显示DataGridView的第一行 [英] datatable.GetChanges() shows always first row of DataGridView

问题描述

我有一个DataGridView，其绑定源绑定到从Oracle数据库加载的数据表。 （顺便说一句，我不认为数据库连接会导致这种情况）

I have a DataGridView with a Binding-Source bound to a Data-Table loaded from an Oracle-Database. (btw. I don't think that the Database-Connection could cause this)

我还有一个绑定到一类人的DataGridViewComboBoxColumn（只有具有 ID和名称），因此我可以显示/允许编辑名称而不是ID。现在我的问题是，数据绑定完成后，c＃自动选择 DGV的第一个单元格-请参见所附图片。

I have also a DataGridViewComboBoxColumn bound to an class of persons (only "has" ID and name), so I can display / allow to edit the name instead of the ID. My problem is now that after the data-binding is completed c# automatically "selects" the first cell of the DGV - see the attached picture.

我还必须使用这段代码来确保数据完整性：

I also have to use this little piece of code to ensure data integrity:

    private void _table_ColumnChanging(object sender, DataColumnChangeEventArgs e)
    {
        if (e.Column == _table.Columns["NEEDED_ID"])
        {
            if (e.ProposedValue == null)
            {
                e.ProposedValue = System.DBNull.Value;
            }
        }
    }

现在使用此_table.GetChanges （）始终将DGV的第一行返回为已修改，但该值并未真正更改-只是 DBNull 而不是 null 。我能以某种方式避免自动选择第一个单元格或如何避免这种行为吗？

Now using this _table.GetChanges() always returns the first row of the DGV as "modified" but the value isn't really changed - it's only DBNull instead of null. Can I somehow avoid automatic selection of first cell or how to avoid this behavior?

编辑：同时，我发现将第一列更改为无法编辑的内容可以解决此问题。但这不过是一种解决方法。

Meanwhile I found out that changing the first column to something not editable fixes this problem. But this is nothing more than an workaround. I would really appreciate to get an working solution for this.

编辑2：我在ComboBox的顶部也有一个空对象-DataSource

EDIT 2: I have also an empty Object 'on top' of the ComboBox-DataSource

  DtoPerson blankPerson = new DtoPerson();
  blankPerson.Name = String.Empty;
  blankPerson.PersonRollenId = -1;
  personList.Add(blankPerson);

推荐答案

尝试在您的DataGridViewComboBoxColumn的数据源中放置一个空值。例如：

Try to put a null in your DataGridViewComboBoxColumn's DataSource. example:

SELECT id, description
FROM yourTable
UNION
SELECT NULL, NULL

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