WPF DataGrid 删除的行不会在数据库中更新(删除)

WPF DataGrid deleted rows don't get updated (deleted) in the database

我的应用中有一个DataGrid,其XML定义如下:

<DataGrid x:Name="grid"
          DockPanel.Dock="Top"
          Visibility="{Binding gridVisibility}"
          CellStyle="{StaticResource ValidationReadyCellStyle}"
          IsSynchronizedWithCurrentItem="True"
          HorizontalAlignment="Stretch"
          HorizontalContentAlignment="Stretch"
          VerticalContentAlignment="Stretch"
          ColumnWidth="*"
          ItemsSource="{Binding DBtable, ValidatesOnExceptions=False,
          NotifyOnSourceUpdated=True, TargetNullValue={x:Static system:String.Empty}, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
          AutoGenerateColumns="True" AutoGeneratingColumn="grid_OnAutoGeneratingColumn" CanUserAddRows="True"
          BeginningEdit="grid_OnBeginningEdit" PreviewKeyDown="grid_OnPreviewKeyDown" RowEditEnding="grid_OnRowEditEnding" CellEditEnding="grid_OnCellEditEnding">
          <DataGrid.RowValidationRules>
              <local:RowValidationChecker ValidationStep="UpdatedValue"/>
          </DataGrid.RowValidationRules>
</DataGrid>

可以看出,ItemsSource绑定了一个名为DBtable的table,根据它自动生成了rows/columns。以下是用于连接和更新数据库的代码片段:

public bool SaveToDB(DataTable table, string tableName)
{
    var msSqlConnectionClass = new MsSqlConnectionClass(MsSqlLogin.Default.Server,
                                                            MsSqlLogin.Default.LoremIpsumDB, MsSqlLogin.Default.UID,
                                                            MsSqlLogin.Default.Password, MsSqlLogin.Default.WinAuth);
    SqlConnection msSqlConnection = msSqlConnectionClass.getMsSqlConnection();
    msSqlConnection.Open();
    try
    {
        string strSQL = "SELECT * FROM " + tableName;
        SqlDataAdapter da = new SqlDataAdapter(strSQL, msSqlConnection);
        SqlCommandBuilder command = new SqlCommandBuilder(da);
        da.UpdateCommand = command.GetUpdateCommand();
        da.DeleteCommand = command.GetDeleteCommand();
        da.InsertCommand = command.GetInsertCommand();
        da.Update(table);
        msSqlConnection.Close();
    }
    catch (Exception e)
    {
        ServiceLog.AddLogInfo(e.ToString());
        msSqlConnection.Close();
        return false;
    }
    return true;
}

问题是,尽管在 DataGrid 中完成的任何添加或编辑操作都在数据库中得到完美更新,但不幸的是,我无法实现相同的删除操作行为。删除是在源本身中完成的,所以当我在删除操作后检查行数时(我使用 DBtable.Rows.RemoveAt()),DBtable 显示该行已被删除,但更改没有在使用上面显示的 SaveToDB() 函数进行更新尝试后反映在数据库中。我该怎么办?

我发现了问题。显然

Dbtable.Rows.RemoveAt(selectedIndex);

不让数据table知道删除命令已经发出。因此,当对数据库执行 运行 更新命令时,不会看到也不会执行任何删除操作。相反,使用

row = DBtable.Rows[selectedIndex];
row.Delete();

解决了问题。

类似的事情也让我很困惑。对于以后搜索时可能遇到此页面的人,这里有一个解决方案。

public DataTable GetMembers()
        {
            conn = new SqlCeConnection(@"Data Source = DataModel.sdf");
            dataAdapter = new SqlCeDataAdapter("Select * from Members", conn);
            commandBuilder = new SqlCeCommandBuilder(dataAdapter);
            dataTable = new DataTable();
            dataAdapter.Fill(dataTable);
            dataTable.RowChanged += new DataRowChangeEventHandler(dataTable_RowChanged);
            dataTable.RowDeleted += new DataRowChangeEventHandler(dataTable_RowDeleted);
            dataTable.DefaultView.ListChanged += DefaultView_ListChanged;
            return dataTable;
        }

        void DefaultView_ListChanged(object sender, System.ComponentModel.ListChangedEventArgs e)
        {
            if (e.ListChangedType == System.ComponentModel.ListChangedType.ItemDeleted)
            {
                try
                {
                    dataAdapter.Update(dataTable);
                }
                catch (Exception ex)
                {
                    System.Windows.MessageBox.Show(ex.Message);
                }
            }
        }