private void Button_Click(object sender, RoutedEventArgs e)        {            Popup1.PlacementTarget = TesTextBox;            Popup1.Placement = PlacementMode.Bottom;            Popup1.IsOpen = true;        }        private void TestDataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)        {            TesTextBox.Text = (dataGrid.SelectedItem as DataRowView).Row["c_AirStrategyExpCode"].ToString();        }

            dataGrid.ItemsSource = ds.Tables[0].DefaultView;            dataGrid.LoadingRow += DataGridOnLoadingRow;

                <StackPanel Orientation="Horizontal" Height="40">                    <TextBlock  Text="ComboBox：" Height="18" Width="70" />                    <Border Height="22" BorderBrush="DarkGray" BorderThickness="1">                        <StackPanel Orientation="Horizontal">                            <TextBlock x:Name="TesTextBox" Height="20" Width="154"/>                            <Button Height="20" Width="14" Click="Button_Click" Style="{StaticResource FrameBtnStyle4}">                                <Popup x:Name="Popup1" Height="300" StaysOpen="False">                                    <Border BorderBrush="DarkGray"  BorderThickness="1">                                        <DataGrid x:Name="dataGrid" GridLinesVisibility = "None" CanUserReorderColumns = "false"                                                  Style="{StaticResource DataGridStyle1}" RowStyle="{StaticResource DataGridRowStyle1}"                                                  CellStyle="{StaticResource DataGridCellStyle1}" ColumnHeaderStyle="{StaticResource DataGridColumnHeaderStyle1}"                                                  IsReadOnly="True" SelectionChanged="TestDataGrid_SelectionChanged"/>                                    </Border>                                </Popup>                            </Button>                        </StackPanel>                    </Border>                </StackPanel>