c# - 语句与 REFERENCE 约束冲突

Question

按钮点击代码

bindingSource1.EndEdit();
            try
            {
                // Delete all the Channels for the current Folder.
                int folderID = (int)RemoveFolderBox.SelectedValue;
                deleteChannels(folderID);

                // Delete the folder itself.
                RSSDataSet1.FolderRow folder = rSSDataSet1.Folder.FindByFolderID(folderID);
                folder.Delete();

                int rowsAffected = folderTableAdapter.Update(rSSDataSet1);

                if (rowsAffected > 0)
                {
                    //statusLabel.Text = "Folder successfully deleted.";
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Problem when deleting folder:" + ex.Message);
            }

删除 channel 功能:<​​/p>

private void deleteChannels(int folderID)
{
    try
    {
       RSSDataSet1.ChannelRow[] channels = (RSSDataSet1.ChannelRow[])rSSDataSet1.Channel.Select("FolderID = " + folderID.ToString());

       foreach (RSSDataSet1.ChannelRow channel in channels)
       {
          int channelID = channel.ChannelID;
          channel.Delete();
       }
       int rowsAffected = channelTableAdapter1.Update(rSSDataSet1);
     }
     catch (Exception ex)
     {
       throw ex;
     }
}

我得到了

The DELETE statement conflicted with the REFERENCE constraint "FK_Channel_Folder". The conflict occurred in database "C:\USERS\ADMIN\DOCUMENTS\VISUAL STUDIO 2010\PROJECTS\PROJ RSS\PROJ RSS\BIN\DEBUG\RSS.MDF", table "dbo.Channel", column 'FolderID'. The statement has been terminated.

Answer 1

如果您尝试删除的项目被删除，您有一个外键引用将被违反。看起来 Channel 有依赖于它的 Folder 实体。

在删除 Channel 之前，您需要删除任何相关的 Folder 实体，或者设置级联删除。