查找并插入列表类集合？

Question

我有一个叫做GroupSelect的类，并制作了一个List(Of GroupSelect)()集合。

现在，我需要找到GroupSelect与RowNo和GroupNo在List(Of GroupSelect)() 如果我发现相同的索引，请更新Value 。 如果找不到，则添加到List(Of GroupSelect) 。

Public Class GroupSelect
    Public Property RowNo() As Integer
        Get
            Return m_RowNo
        End Get
        Set(ByVal value As Integer)
            m_RowNo = value
        End Set
    End Property
    Private m_RowNo As Integer
    Public Property GroupNo() As Integer
        Get
            Return m_GroupNo
        End Get
        Set(ByVal value As Integer)
            m_GroupNo = value
        End Set
    End Property
    Private m_GroupNo As Integer

    Private m_Value As Integer
    Public Property Value() As Integer
        Get
            Return m_Value
        End Get
        Set(ByVal value As Integer)
            m_Value = value
        End Set
    End Property

End Class

在协作中找到该对象

                grpSelect.RowNo = rowNo
                grpSelect.GroupNo = grpNo
                grpSelect.Value = CType(CType(row.FindControl("txtCombine"), 
TextBox).Text, Integer)

这个怎么做？

Answer 1

假设收集您的List(Of GroupSelect)和RowNo ， GroupNo是你正在检查againt的价值观和Value是新价值

Dim item As GroupSelect = collection.Where(Function(i) i.RowNo = RowNo AndAlso i.GroupNo = GroupNo).SingleOrDefault()

If item Is Nothing Then
    Dim newItem As New GroupSelect()
    newItem.GroupNo = GroupNo
    newItem.RowNo = RowNo

    newItem.Value = Value

    collection.Add(newItem)
Else
    item.Value = Value
End If

SingleOrDefault()在您的情况下应该是理想的，因为它看起来像您永远不会有多个符合条件的项目。 但是用Try..Catch包围查询可能是一个好主意。