h：commandButton里面的h：dataTable

问题描述

我正在使用一个JSF数据表。表中的列之一是命令按钮。

当单击此按钮时，我需要传递几个参数（如所选行的值），使用表达式语言。这个参数需要传递给可以在其上执行方法的JSF托管bean。

我使用了以下代码片段，但是我在JSF bean总是为空。

 < h：column> 
< f：facet name =header> 
< h：outputText value =跟随/> 
< / f：facet> 
 
< h：commandButton id =FollwDocaction =＃{usermanager.followDoctor}value =跟随/> 
< h：inputHidden id =id1value =＃{doc.doctorid}/> 
< / h：column> 
  

Bean方法：

  public void followDoctor（）{
 FacesContext context = FacesContext.getCurrentInstance（）; 
 Map requestMap = context.getExternalContext（）。getRequestParameterMap（）; 
 String value =（String）requestMap.get（id1）; 
 System.out.println（Doctor added to patient List+ value）; 
} 
  

如何使用命令按钮将值传递给JSF托管bean？ p>

解决方案

使用以获取当前行的操作方法。

  @ManagedBean 
 @ViewScoped 
 public class Usermanager {
 private List& Doctor>医生; 
 private DataModel& Doctor>医生模型
 
 @PostConstruct 
 public void init（）{
 doctors = getItSomehow（）; 
 datamodel = new ListDataModel& Doctor>（医生）; 
} 
 
 public void followDoctor（）{
 Doctor selectedDoctor = doctorModel.getRowData（）; 
 // ... 
} 
 
 // ... 
} 
  

在datatable中使用它。

 < h：dataTable value = ＃{usermanager.doctorModel}var =doc> 
  

并摆脱那个 h：inputHidden 在视图中 h：commandButton 旁边。

---

没有优雅的选择是使用 f：setPropertyActionListener 。

  public Usermanager类{
 private Long doctorId; 
 
 public void followDoctor（）{
 Doctor selectedDoctor = getItSomehowBy（doctorId）; 
 // ... 
} 
 
 // ... 
} 
  

使用以下按钮：

 < h：commandButton action =＃ usermanager.followDoctor}value =跟随> 
< f：setPropertyActionListener target =＃{usermanager.doctorId}value =＃{doc.doctorId}/> 
< / h：commandButton> 
  

---

相关：

• 的好处和陷阱 - 包含使用 DataModel< E> 的CRUD示例。 li>
  

I am using a JSF data table. One of the columns in the table is a Command button.

When this button is clicked I need to pass few parameters (like a value of the selected row) using the Expression language. This paramaters need to be passed to the JSF managed bean which can execute methods on them.

I have used the following snippet of code but the value i am getting on the JSF bean is always null.

<h:column>
    <f:facet name="header">
        <h:outputText value="Follow"/>
    </f:facet>

    <h:commandButton id="FollwDoc" action="#{usermanager.followDoctor}" value="Follow" />
    <h:inputHidden id="id1" value="#{doc.doctorid}" />
</h:column>

Bean Method:

public void followDoctor() {
    FacesContext context = FacesContext.getCurrentInstance();
    Map requestMap = context.getExternalContext().getRequestParameterMap();
    String value = (String)requestMap.get("id1");
    System.out.println("Doctor Added to patient List"+ value);
}

How can I pass values to the JSF managed bean with a commandbutton?

解决方案

Use DataModel#getRowData() to obtain the current row in action method.

@ManagedBean
@ViewScoped
public class Usermanager {
    private List<Doctor> doctors;
    private DataModel<Doctor> doctorModel;

    @PostConstruct
    public void init() {
        doctors = getItSomehow();
        datamodel = new ListDataModel<Doctor>(doctors);
    }

    public void followDoctor() {
        Doctor selectedDoctor = doctorModel.getRowData();
        // ...
    }

    // ...
}

Use it in the datatable instead.

<h:dataTable value="#{usermanager.doctorModel}" var="doc">

And get rid of that h:inputHidden next to the h:commandButton in the view.

---

An -less elegant- alternative is to use f:setPropertyActionListener.

public class Usermanager {
    private Long doctorId;

    public void followDoctor() {
        Doctor selectedDoctor = getItSomehowBy(doctorId);
        // ...
    }

    // ...
}

With the following button:

<h:commandButton action="#{usermanager.followDoctor}" value="Follow">
    <f:setPropertyActionListener target="#{usermanager.doctorId}" value="#{doc.doctorId}" />
</h:commandButton>

---

Related:

• The benefits and pitfalls of @ViewScoped - Contains CRUD example using DataModel<E>.

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