如何在变更事件触发时计算指定任务的自定义字段值？

能否编写脚本，在变更事件触发后仅对单个任务的字段执行计算？目前我有一个针对MS Project文件中所有任务计算的脚本，希望改成只处理目标任务。

我尝试相关内容但未成功实现，现有代码如下：

类模块 cm_Events #

Public WithEvents MyMSPApp As MSProject.Application

Private Sub Class_Initialize()
    Set MyMSPApp = Application
End Sub

Private Sub MyMSPApp_ProjectBeforeAssignmentChange(ByVal Assgn As Assignment, ByVal Field As PjField, ByVal NewVal As Variant, Cancel As Boolean)
    If EnableEvents Then
        EnableEvents = False
        Dim X As Integer
        X = 5
        Debug.Print X
        EnableEvents = True
    End If
End Sub

标准模块 m_Events #

Public oMSPEvents As New cm_Events
Public EnableEvents As Boolean

Sub StartEvents()
    Set oMSPEvents.MyMSPApp = Application
    EnableEvents = True
End Sub

Project对象代码 #

Private Sub Project_Open(ByVal pj As Project)
    Call m_Events.StartEvents
End Sub

我希望将以下计算逻辑加入ProjectBeforeAssignmentChange事件中：

tsk.Cost5 = 0
Dim Assgn As Assignment
For Each Assgn In tsk.Assignments
    If Assgn.Resource.Text1 = "Labor" Then
        tsk.Cost5 = tsk.Cost5 + Assgn.Cost
        Assgn.Cost5 = Assgn.Cost5 + Assgn.Cost
    End If
Next Assgn

完全可行，只需将计算逻辑与事件触发时的关联任务绑定即可，关键是通过Assgn.Task获取当前变更对应的任务，同时避免事件循环。修改后的代码如下：

修改后的类模块 cm_Events #

Public WithEvents MyMSPApp As MSProject.Application

Private Sub Class_Initialize()
    Set MyMSPApp = Application
End Sub

Private Sub MyMSPApp_ProjectBeforeAssignmentChange(ByVal Assgn As Assignment, ByVal Field As PjField, ByVal NewVal As Variant, Cancel As Boolean)
    If EnableEvents Then
        EnableEvents = False
        
        ' 获取当前变更关联的任务
        Dim tsk As Task
        Set tsk = Assgn.Task
        
        ' 执行目标计算逻辑
        tsk.Cost5 = 0
        Dim currAssgn As Assignment
        For Each currAssgn In tsk.Assignments
            If currAssgn.Resource.Text1 = "Labor" Then
                tsk.Cost5 = tsk.Cost5 + currAssgn.Cost
                currAssgn.Cost5 = currAssgn.Cost5 + currAssgn.Cost
            End If
        Next currAssgn
        
        EnableEvents = True
    End If
End Sub

关键说明 #

• 通过Assgn.Task直接获取变更操作对应的任务，无需遍历所有任务，实现单任务精准计算
• 保留EnableEvents开关，避免修改字段时再次触发事件导致循环
• 将循环变量名改为currAssgn，避免与事件参数的Assgn重名，防止变量冲突

测试步骤 #

1. 保存所有修改并重启MS Project
2. 打开目标项目文件，事件会自动启动（通过Project_Open触发）
3. 修改任意任务的分配信息，查看该任务的Cost5字段是否按预期更新

内容的提问来源于stack exchange，提问作者BP130