Primefaces数据表项选择，确认对话框和RequestContext(Primefaces Datatable item selection, confirmation dialog and RequestContext)

 编辑：在构建视图时，在@PostContsruct init（） - 该视图的支持bean类的方法中尝试填充集合后，一切正常。 它是@ViewScoped。 所以问题在于组件以某种方式不能识别用作数据表值的集合，实际上具有值，因为它以不常见的方式填充。 无论如何，如果我在视图构建时填充集合，一切都很完美。 但当然这不是解决方案，因为必须在提到的模糊ajax事件上填充集合。 所以这是一种生命周期/范围问题。 
 
 EDIT2：我试图将表格添加到与其中具有ajax模糊效果的组件相同的表单中，在弹出窗口中显示弹出窗口和数据表并填充集合。 这也有效。 所以，不知何故，ajax模糊事件和数据表功能的生命周期/范围不同，因为它们的格式不同。 现在我应该以某种方式设法将它们保持在同一范围内，同时在弹出对话框中具有数据表。 现在，数据表笨拙地以相同的形式驻留在上述测试目的中。 
 
 我在p:confirmDialog有一个Primefaces p:dataTable ，当我选择一个项目时，该项目的setter只获得null值。 因此设置了null值，并且以下操作显然不起作用，因为我们没有要使用的值。 
 
 我认为问题与我必须使用RequestContext来显示对话框有关。 这是因为在窗体的blur事件中检查集合时应显示该对话框。 
 
 首先，从InputText检查blur事件： 
 
<p:inputText id="customerIdInput"
             value="#{newCustomerCaseController.id}"
             label="custId" required="true">
    <f:ajax event="blur" listener="#{newCustomerCaseController.performBackgroundSearch}" />
</p:inputText>
 
 然后，在该blur事件上，将在辅助bean中调用一个侦听器方法，该方法通过RequestContext显示一个对话框，如下所示： 
 
public void performBackgroundSearch() {
    showPopUpBecauseCertainConditionsAreMet();
}

public void showPopUpBecauseCertainConditionsAreMet() {

    setExistingCustomerCases(customerCaseService.searchByEmployerId(employerId));
    RequestContext.getCurrentInstance().update("caseform");
    RequestContext.getCurrentInstance().execute(
            "PF('employerAlreadyHasCustomerCasesDialog').show()");
    }
}
 
 这是xhtml中的确认对话框和表格： 
 
<p:confirmDialog widgetVar="employerAlreadyHasCustomerCasesDialog" width="500" appendTo="@(body)" showEffect="fade" hideEffect="fade"
                 closable="false" >
<h:form id="caseform">
        <p:dataTable id="casetable"  var="custcase" rowKey="#{custcase.caseId}" value="#{newCustomerCaseController.existingCustomerCases}"
                     selectionMode="single" selection="#{newCustomerCaseController.selectedAlreadyExistingCustomerCase}" >
            <p:ajax event="rowSelect" process="@this" listener="#{newCustomerCaseController.onExistingCaseRowSelect()}" />
            <p:column headerText="caseId">
                <h:outputText value="#{custcase.caseId}" />
            </p:column>
        </p:dataTable>
</h:form>
<!--some unimportant buttons which we don't touch in this example-->
</p:confirmDialog>
 
 最后，让我们看看onExistingCaseRowSelect侦听器方法的作用。 它只尝试重定向，就像使用我们尝试在p:dataTable选择的customerCase的caseId导航到不同的url一样。 
 
public void onExistingCaseRowSelect(SelectEvent event) {
    try {
        facesContext.getExternalContext().redirect("/customercase.xhtml?caseId=" + selectedAlreadyExistingCustomerCase.getCaseId());
    }catch (Exception e) {
    }
}
 
 这里的问题是，当在表中单击时， selectedAlreadyExistingCustomerCase不会在辅助bean中设置。 单击表中的行时，将设置null 。 我在getter和setter中用printlines检查过这个。 我认为这里的问题是由于通过RequestContext.getCurrentInstance().update("componentName");视图而发生了一些事情RequestContext.getCurrentInstance().update("componentName"); 
 
 如何将表中单击的行值 - 一个customerCase - 设置为辅助bean中的选定值，而不是null ？ 

EDIT: Everything worked after I tried to populate the collection when the view is constructed, in the @PostContsruct init()-method of that view's backing bean class. It is @ViewScoped. So the problem lies in that the component somehow doesn't recognize the collection that is used as a value of the datatable, actually having values because it is populated in an uncommon way. Anyway, everything works perfectly if I populate the collection when the view builds. But of course that's not a solution because the collection must be populated on that mentioned blur ajax event. So it's some kind of a lifecycle / scope problem.
 
EDIT2: I tried to add the table to the same form as the component that has ajax blur effect in it, showing the popup and the datatable in that popup and populating the collection. That worked too. So, somehow the lifecycle / scope was different in that ajax blur event and the datatable functionality since they were in different forms. Now I should somehow manage to keep them in the same scope while having the datatable in the popup dialog. Now the datatable clumsily resides in the same form for aforementioned testing purposes.
 
I have a Primefaces p:dataTable in a p:confirmDialog and when I select an item, the setter of that item just gets null value. So a null value is set and the following operation obviously doesn't work because we don't have a value to work with.
 
I think the problem has something to do with me having to use RequestContext to show the dialog. This is because the dialog should be shown when a collection is checked in a blur event of a form.
 
First, a blur event is checked from a InputText:
 
<p:inputText id="customerIdInput"
             value="#{newCustomerCaseController.id}"
             label="custId" required="true">
    <f:ajax event="blur" listener="#{newCustomerCaseController.performBackgroundSearch}" />
</p:inputText>
 
Then, on that blur event a listener method will be called in the backing bean, which shows a dialog via RequestContext as follows:
 
public void performBackgroundSearch() {
    showPopUpBecauseCertainConditionsAreMet();
}

public void showPopUpBecauseCertainConditionsAreMet() {

    setExistingCustomerCases(customerCaseService.searchByEmployerId(employerId));
    RequestContext.getCurrentInstance().update("caseform");
    RequestContext.getCurrentInstance().execute(
            "PF('employerAlreadyHasCustomerCasesDialog').show()");
    }
}
 
Here's the confirm dialog and table in xhtml:
 
<p:confirmDialog widgetVar="employerAlreadyHasCustomerCasesDialog" width="500" appendTo="@(body)" showEffect="fade" hideEffect="fade"
                 closable="false" >
<h:form id="caseform">
        <p:dataTable id="casetable"  var="custcase" rowKey="#{custcase.caseId}" value="#{newCustomerCaseController.existingCustomerCases}"
                     selectionMode="single" selection="#{newCustomerCaseController.selectedAlreadyExistingCustomerCase}" >
            <p:ajax event="rowSelect" process="@this" listener="#{newCustomerCaseController.onExistingCaseRowSelect()}" />
            <p:column headerText="caseId">
                <h:outputText value="#{custcase.caseId}" />
            </p:column>
        </p:dataTable>
</h:form>
<!--some unimportant buttons which we don't touch in this example-->
</p:confirmDialog>
 
Lastly, let's see what the onExistingCaseRowSelect listener method does. It only tries to redirect, as in navigate to different url using the caseId of that customerCase that we try to select in the p:dataTable.
 
public void onExistingCaseRowSelect(SelectEvent event) {
    try {
        facesContext.getExternalContext().redirect("/customercase.xhtml?caseId=" + selectedAlreadyExistingCustomerCase.getCaseId());
    }catch (Exception e) {
    }
}
 
The problem here is that the selectedAlreadyExistingCustomerCase doesn't get set in the backing bean when it is clicked in the table. A null is being set when I click the row in the table. I've checked this with printlines in getter and setter. I think the problem here is that something happens because of the update of the view via RequestContext.getCurrentInstance().update("componentName");
 
How can I get the clicked row value in the table - a customerCase that is - to be set as the selected value in the backing bean, instead of a null?

原文：https://stackoverflow.com/questions/39330729