Question

我的班级中有一个方法，它返回一个数据列表

Private Function GetCertificationLevels() 
            Dim theProgramYearID As Int32 = Convert.ToInt32(lstProgramYear.SelectedValue)
            Dim thePositionGroupID As Int32 = Convert.ToInt32(lstPositionGroup.Selected)
            Dim theCategoryID As Int32 = Convert.ToInt32(lstCategory.SelectedValue)
            filterLevels = _curTree.GetCertificationLevelsList(theProgramYearID, thePositionGroupID, theCategoryID)
            Return filterLevels
        End Function

我想只检索_data值（ 5261,5263,5262,5264和5260 ）

如何进行？

Answer 1

如果我理解您的问题，那么您正尝试在另一个过程中使用变量theProgramYearID，thePositionGroupID和theCategoryID的值。我将创建一个包含ByRef参数的重载过程，然后在另一个过程中使用它们。

Private Sub CallingProcedure()
    'Declare variables to hold the ByRef results.
    Dim locYearID, locGroupID, locCategoryID as Integer

    'Call the procedure, and pass the variables for processing
    Dim FunctionResult = GetCertificationLevels(locYearID, locGroupID, locCategoryID)

    'Now do whatever you need with the modified variables
    SomeOtherProcedure()
End Sub

Private Overloads Function GetCertificationLevels(ByRef theProgramYearID as Int32, ByRef thePositionGroupID as Int32, ByRef theCategoryID as Int32) 
    theProgramYearID = Convert.ToInt32(lstProgramYear.SelectedValue)
    thePositionGroupID = Convert.ToInt32(lstPositionGroup.Selected)
    theCategoryID = Convert.ToInt32(lstCategory.SelectedValue)
    filterLevels = _curTree.GetCertificationLevelsList(theProgramYearID, thePositionGroupID, theCategoryID)
    Return filterLevels
End Function

ByRef将确保函数正在修改传递给它的变量，并且它们将在函数中分配给它们的值。

Answer 2

使用LINQ：

Return filterLevels.Select(Function(t) t.Data).ToList()

如何从函数返回获取特定数据

2 个答案: