Question

我正在尝试在datagridview中显示我的数据。我创建了一个具有不同属性的类，并使用其列表作为数据源。它工作得很好。但是如果我们有嵌套类，我会感到很困惑。

我的课程如下：

class Category
   property UIN as integer
   property Name as string
end class

class item
   property uin as integer
   property name as string
   property mycategory as category
end class

我的数据列表如下：

dim myDataList as list(of Item) = new List(of Item)
myDataList.Add(new Item(1,"item1",new category(1,"cat1")))
myDataList.Add(new Item(2,"item2",new category(1,"cat1")))
myDataList.Add(new Item(3,"item3",new category(1,"cat1")))
myDataList.Add(new Item(4,"item4",new category(2,"cat2")))
myDataList.Add(new Item(5,"item5",new category(2,"cat2")))
myDataList.Add(new Item(6,"item6",new category(2,"cat2")))

现在我将datagridview控件绑定为：

DGVMain.AutoGenerateColumns = False
DGVMain.ColumnCount = 3
DGVMain.Columns(0).DataPropertyName = "UIN"
DGVMain.Columns(0).HeaderText = "ID"
DGVMain.Columns(1).DataPropertyName = "Name"
DGVMain.Columns(1).HeaderText = "Name"
DGVMain.Columns(2).DataPropertyName = "" **'here i want my category name**
DGVMain.Columns(2).HeaderText = "category"

DGVMain.datasource = myDataList
DGVMain.refresh()

我尝试过使用mycategory.name但是没有用。可以做些什么来获得预期的结果？除此之外还有更好的想法来完成同样的任务吗？

根据评论编辑我的问题：

我检查了你给出的链接。这很好，非常有用。由于代码在c＃中，我试图在vb中转换它。一切顺利，但在区分大小写的情况下失败了，接下来的一个是我有我的嵌套类名itemcategory，我的属性名是category。它引起了这个问题。它没有搜索类别，但搜索了itemcategory。很困惑。我的代码如下：

Private Sub DGVMain_CellFormatting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) Handles DGVMain.CellFormatting
    Dim DGVMain As DataGridView = CType(sender, DataGridView)
    e.Value = EvaluateValue(DGVMain.Rows(e.RowIndex).DataBoundItem, DGVMain.Columns(e.ColumnIndex).DataPropertyName)
End Sub

Private Function EvaluateValue(ByRef myObj As Object, ByRef myProp As String) As String
    Dim Ret As String = ""
    Dim Props As System.Reflection.PropertyInfo()
    Dim PropA As System.Reflection.PropertyInfo
    Dim ObjA As Object

    If myProp.Contains(".") Then

        myProp = myProp.Substring(0, myProp.IndexOf("."))
        Props = myObj.GetType().GetProperties()

        For Each PropA In Props

            ObjA = PropA.GetValue(myObj, New Object() {})
            If ObjA.GetType().Name = myProp Then

                Ret = EvaluateValue(ObjA, myProp.Substring(myProp.IndexOf(".") + 1))
                Exit For

            End If

        Next

    Else

        PropA = myObj.GetType().GetProperty(myProp)
        Ret = PropA.GetValue(myObj, New Object() {}).ToString()

    End If

    Return Ret
End Function

Answer 1

我只需向名为item的{{1}}添加一个返回CategoryName并使用该属性的属性。

类别是Item的一部分，但这并不意味着您总是必须将整个Category的访问权限授予外部类，只需访问当时需要访问的位以最大化封装并尽量减少相互依赖。

编辑：回复您的评论

如果您不想创建我在上面的答案中提到的属性，我认为没有任何真正的解决方案，但您可以使用'CellFormatting'事件进行排序，让它在您设置{的地方工作{1}}到特殊标识符，然后在Category.Name事件处理程序中查找要显示的实际值。您可以找到here的示例，查找tkrasinger的帖子（如果您想使用反射，则查找AlexHinton的帖子）。

Answer 2

Public Class Category
    Dim uni As Integer
    Dim name As String
    Public Sub New(ByVal i As Integer, ByVal n As String)
        Me.UIN = i
        Me.name = n
    End Sub
    Public Sub New()

    End Sub
    Property UIN() As Integer
        Get
            Return uni


        End Get
        Set(ByVal value As Integer)
            uni = value

        End Set
    End Property
    Property Names() As String
        Get
            Return Me.name

        End Get
        Set(ByVal value As String)
            Me.name = value
        End Set
    End Property
    **Public Overrides Function ToString() As String
        Return name.ToString()
    End Function**
End Class

Public Class item
    Dim uni As Integer
    Dim name As String
    Dim category As New Category()

    Property UIN() As Integer
        Get
            Return uni


        End Get
        Set(ByVal value As Integer)
            uni = value

        End Set
    End Property
    Property Names() As String
        Get
            Return Me.name

        End Get
        Set(ByVal value As String)
            Me.name = value
        End Set
    End Property
    Property mycategory() As Category
        Get
            Return Me.category
        End Get
        Set(ByVal value As Category)
            Me.category = value
        End Set
    End Property
    Public Sub New(ByVal i As Integer, ByVal nm As String, ByVal ct As Category)
        Me.UIN = i
        Me.Names = nm
        Me.mycategory = ct
    End Sub
End Class

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Dim myDataList As List(Of item) = New List(Of item)
    myDataList.Add(New item(1, "item1", New Category(1, "cat1")))
    myDataList.Add(New item(2, "item2", New Category(1, "cat1")))
    myDataList.Add(New item(3, "item3", New Category(1, "cat1")))
    myDataList.Add(New item(4, "item4", New Category(2, "cat2")))
    myDataList.Add(New item(5, "item5", New Category(2, "cat2")))
    myDataList.Add(New item(6, "item6", New Category(2, "cat2")))


    DGVMain.AutoGenerateColumns = False
    DGVMain.ColumnCount = 3
    DGVMain.Columns(0).DataPropertyName = "UIN"
    DGVMain.Columns(0).HeaderText = "ID"
    DGVMain.Columns(1).DataPropertyName = "Names"
    DGVMain.Columns(1).HeaderText = "Name"
    **DGVMain.Columns(2).DataPropertyName = "mycategory"**
    DGVMain.Columns(2).HeaderText = "Category"

    DGVMain.datasource = myDataList
    DGVMain.refresh()
End Sub

如何在datagridview中将类属性指定为显示数据成员

2 个答案: