修复DataGridTemplateColumn选择时不现实Description的问题

Views/VariableTableView.xaml

@@ -170,7 +170,13 @@
                     <DataGridTemplateColumn.CellEditingTemplate>
                         <DataTemplate>
                             <ComboBox ItemsSource="{Binding Source={StaticResource signalType}}"
-                                      SelectedItem="{Binding SignalType}" />
+                                      SelectedItem="{Binding SignalType}">
+                                <ComboBox.ItemTemplate>
+                                    <DataTemplate>
+                                        <TextBlock Text="{Binding Converter={StaticResource EnumDescriptionConverter}}"/>
+                                    </DataTemplate>
+                                </ComboBox.ItemTemplate>
+                            </ComboBox>
                         </DataTemplate>
                     </DataGridTemplateColumn.CellEditingTemplate>
                 </DataGridTemplateColumn>