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vb.net - VB WindowsForm 自定义类事件处理程序问题

问题描述

我创建了一个自定义类 (DataGroupBoxControl)，它基本上是一个 GroupBox，里面有一个或多个面板。每个面板并排放置两个标签，如下图所示。 在此处输入图像描述

该对象允许将 DataTable 传递给它，这决定了创建和显示多少行面板。我希望用户能够单击其中一个面板标签并执行“某事”。

这是创建标签的类中的过程。

Public Class DataGroupBoxControl
Inherits GroupBox

Public DataLabels As New List(Of DataLabelControl)

Public Sub BindData(ByVal ds As DataTable)
    Dim colItem As Integer = 0
    For Each col As DataColumn In ds.Columns
        DataLabels.Add(New DataLabelControl)
        For Each row As DataRow In ds.Rows
            DataLabels(colItem).TitleLabel.Text = col.ColumnName & " " & _Separator
            DataLabels(colItem).TitleLabel.Name = col.ColumnName
            If IsNumeric(row.Item(colItem)) Then
                If row.Item(colItem).ToString.IndexOf(".") <> -1 Then
                    DataLabels(colItem).ValueLabel.Text = Decimal.Parse(row.Item(colItem)).ToString("c")
                Else
                    DataLabels(colItem).ValueLabel.Text = row.Item(colItem)
                End If
            End If
            DataLabels(colItem).ValueLabel.Name = row.Item(colItem)
            DataLabels(colItem).Top = (colItem * DataLabels(colItem).Height) + 20
            DataLabels(colItem).Left = 5
            Me.Controls.Add(DataLabels(colItem))
            Me.Height = Me.Height + DataLabels(colItem).Height
            DataLabels(colItem).Show()
        Next
        colItem += 1
    Next
End Sub

在哪里以及如何创建标签点击事件处理程序？然后使用以下对象从我的主窗体访问该事件：

Public AccountsGroupBox As New DataGroupBoxControl

标签： vb.netonclickdelegatesevent-handlingaddhandler

解决方案

在创建 DataLabelControl 之前，使用 AddHandler 附加事件处理程序，例如。到 TitleLabel 控件，然后您可以侦听事件并引发可以在父控件中处理的新事件。

Public Class SomeForm
    Private WithEvents AccountsGroupBox As New DataGroupBoxControl

    Private Sub AccountsGroupBox_ItemClick(
              sender As Object, 
              args As ItemClickEventArgs) Handles AccountsGroupBox.ItemClick

    End Sub
End Class

Public Class ItemClickEventArgs
    Inherits EventArgs
    Public Property Control As Object
End Class

Public Class DataGroupBoxControl
    Inherits GroupBox

    Public Event ItemClick(sender As Object, args As ItemClickEventArgs)

    Public DataLabels As New List(Of DataLabelControl)

    Private Sub OnLabelClick(sender As Object, args As EventArgs)
        RaiseEvent ItemClick(Me, New ItemClickEventArgs With {.Control = object})
    End Sub

    Public Sub BindData(ByVal ds As DataTable)

        For Each col As DataColumn In ds.Columns

            Dim control = New DataLabelControl
            AddHandler control.TitleLabel.Click, AddressOf OnLabelClick

            DataLabels.Add(control)

            ' ...
        Next
    End Sub
End Class

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