Question

您好我已经构建了两个连续的下拉列表，其中一个是在init（）方法中初始化的，另一个是在第一个选择的基础上填充的。

命令按钮用于同时使用所选值进行处理，Strange表示所选值的Setter被调用两次（第二次设置为空白......我在调试中发现）..我需要理解为什么我是得到空白值？

myPage.xhtml

<p:selectOneMenu id="dbList"
    value="#{backingBean.selectedConnection}"
    style="width:200px">
    <p:ajax listener="#{backingBean.onConnectionChange()}"
        update="aliasList" />
    <f:selectItem itemLabel="Select" itemValue="#{backingBean.selectedConnection}"
        noSelectionOption="false" />
    <f:selectItems value="#{backingBean.connectionsTypeList}" />
</p:selectOneMenu>
<p:outputLabel for="aliasList" value="Connection Alias" />
<p:selectOneMenu id="aliasList"
    value="#{backingBean.aliasSelected}" style="width:200px">
    <f:selectItem itemLabel="Select" itemValue="#{backingBean.aliasSelected}"
        noSelectionOption="false"/>
    <f:selectItems value="#{backingBean.connectionsList}" />
</p:selectOneMenu>
<p:commandButton value="myButton" 
    actionListener="#{backingBean.myMethod()}"
    id="myButton" />

backingBean.java

@ManagedBean
@ViewScoped
public class BackingBean implements Serializable {
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private ArrayList<String> connectionsList;
    private String aliasSelected;
    private String selectedConnection;
    private ArrayList<String> connectionsTypeList;

    @PostConstruct
    public void init() {
        // Initialize the connection alias drop down here
        this.connectionsTypeList = getConnectionTypeList();
        this.connectionsList=new ArrayList<String>();
    }

    public void onConnectionChange() {
        System.out.println("In Connection Change, populating aliases");
        getConnectionDBList();

    }
    public String getAliasSelected() {
        return aliasSelected;
    }
//Dont know why this is called twice on button click and second time value set is blank
    public void setAliasSelected(String aliasSelected) {
        this.aliasSelected = aliasSelected;
    }

    public ArrayList<String> getConnectionsList() {
        return connectionsList;
    }

    public void setConnectionsList(ArrayList<String> connectionsList) {
        this.connectionsList = connectionsList;
    }
    public String getSelectedConnection() {
        return selectedConnection;
    }

    public void setSelectedConnection(String selectedConnection) {
        this.selectedConnection = selectedConnection;
    }

    public ArrayList<String> getConnectionsTypeList() {
        return connectionsTypeList;
    }

    public void setConnectionsTypeList(ArrayList<String> connectionsTypeList) {
        this.connectionsTypeList = connectionsTypeList;
    }
    public void myMethod() {
        System.out.println("selected Alias is "+aliasSelected);
        System.out.println("selected connection is "+selectedConnection);
    }
}

新的表面，请帮助

Answer 1

回答这个问题：“第二次设置为空白......我发现在调试中” 这种情况正在发生，因为我意识到我将相同的属性指向两个ui组件..在...同一页面中的两个下拉列表链接到支持bean的相同属性.Sillyh Mistake ..因此第二次调用setter..with空白值..因为它没有为第二个UI组件初始化

没有从primefaces支持bean中的Dropdown中获取选定值

1 个答案: