如何将 Flex Combobox 中的预设值处理为选中项

Question

我的 Flex 程序遇到了一个非常基本但令人讨厌的问题。

长话短说，我有一个 DataGrid，其中每一行（您已经可以动态地添加和删除行）都有一个基于元素 ArrayCollection 的组合框（responsabili), 对组合框的每个更改都已经存储了对数据库的更改。我希望组合框显示从数据库加载的值作为选定值。

<s:Panel title="qqq" width="100%" height="100%" styleName="light">
    <s:layout>
        <s:VerticalLayout paddingBottom="10" paddingLeft="10" paddingRight="10" paddingTop="10" />
    </s:layout>
    <s:VGroup width="100%" height="100%">
        <mx:Text text="www" />
        <components:GraphicButton styleName="add" toolTip="Aggiungi elemento" id="aggCompito" click="aggCompito_clickHandler(event)"/>
        <s:DataGrid width="100%" height="100%" dataProvider="{MyModel.instance.compiti}" editable="true" gridItemEditorSessionSave="changeHandler(event)">
            <s:columns>
                <s:ArrayList>
                    <s:GridColumn headerText="Responsabile" editable="false" width="180">
                        <s:itemRenderer>
                            <fx:Component>
                                <s:GridItemRenderer>
                                    <fx:Script>
                                        <![CDATA[
                                        import it.aaa.frontend.model.MyModel;

                                        import mx.binding.utils.ChangeWatcher;
                                        import mx.collections.ArrayCollection;
                                        import mx.controls.Alert;
                                        import mx.core.FlexGlobals;
                                        import mx.events.CloseEvent;
                                        import mx.events.IndexChangedEvent;

                                        import spark.events.IndexChangeEvent;

                                        protected function changeHandler(event:IndexChangeEvent):void {
                                            data.responsabile = myResponsabile.selectedItem;
                                            // TODO Auto-generated method stub
                                            data.tipo = event.newIndex;
                                            dispatchEvent(new Event("compitiChange", true));
                                        }

                                        protected function responsabililabelFunc(item:Object):String {
                                            return String(item.cognome) + " " + String(item.nome);
                                        }

                                        protected function guessSelectedItem(item:Object):int {
                                            return item.responsabile.id;
                                        }

                                        ]]>
                                    </fx:Script>
                                    <s:HGroup>
                                        <s:ComboBox id="myResponsabile"
                                                    dataProvider="{MyModel.instance.responsabili}"
                                                    change="changeHandler(event)"
                                                    labelFunction="responsabililabelFunc"
                                                    selectedItem="{data.responsabile}"
                                                />
                                    </s:HGroup>
                                </s:GridItemRenderer>
                            </fx:Component>
                        </s:itemRenderer>
                    </s:GridColumn>
                </s:ArrayList>
            </s:columns>
        </s:DataGrid>
    </s:VGroup>
</s:Panel>

MyModel.as

public var responsabili:ArrayCollection; //initialized with actual ArrayCollection of "responsabili", with id, cognome, nome.

Answer 1

如果您使用某些动作脚本类作为您的数据对象并且属性 resposabile 被标记为可绑定，则它仅适用于 selectedItem="{data.responsabile}"：

[Bindable] public var responsabile:Object;

如果您只有一些通用对象作为数据，则需要在 itemrenderer 中设置数据的地方进行处理。所以你的 GridItemRenderer 需要另一种方法：

override public function set data(value:Object):void
{
    super.data = value;

    // only do something if the data is set. When the renderer is destroyed the data will be null
    if (data)
    {
       myResponsabile.selectedItem = data.responsabile;
    }
}

我不记得数据是在创建所有组件（包括您的组合框）之后还是之前设置的。所以万一你会得到一个空指针异常，因为此时 myResponsabile 为空，它会变得更复杂：

private var _myResponsabile:Object;
private var _myResponsabileChanged:Boolean;

override public function set data(value:Object):void
{
    super.data = value;

    // only do something if the data is set. When the renderer is destroyed the data will be null
    if (data)
    {
       _myResponsabile = data.responsabile;
       _myResponsabileChanged = true;
       invalidateProperties();
    }
}

override protected function commitProperties():void
{
    super.commitProperties();

    if(_myResponsabileChanged)
    {
        _myResponsabileChanged = false;
        myResponsabile.selectedItem = _myResponsabile;
    }
}

如何将 Flex Combobox 中的预设值处理为选中项

How to handle pre-set value in Flex Combobox as selected item

apache-flex

combobox