Question

如何使用外部组件对listview值进行排序？这意味着，用户不要单击列表视图的标题，而是选择服务于用户可以排序的特定标题的组合框值。我在listview中有大约6列。我只需要通过选择组合框来对这个列表视图进行排序，我将编写一个代码来根据combobox1.text值对listview进行排序。任何想法？

Answer 1

您需要编写一个实现System.Collection.IComparer的类，并根据您的下拉值设置比较规则。那么你需要使用你编写的比较器的实例设置listview ListViewItemSorter属性，并将其命名为Sort方法。

Answer 2

我终于找到了一些问题的答案。我要做的就是为我的评论中的@zohar建议为IComparer创建另一个类。请在下面找到我的答案：我的列表视图名称是lvshop。

在课程顶部，声明：

Imports System
Imports System.Windows.Forms
Imports System.Drawing
Imports System.Collections

在课堂上，声明：

Private m_SortingColumn As ColumnHeader

在Windows加载时，我创建了一个列标题：

lvShop.View = View.Details
lvShop.Columns.Add("Shop No", 70, HorizontalAlignment.Left)
lvShop.Columns.Add("Shop Name", 170, HorizontalAlignment.Left)
lvShop.Columns.Add("Shop Details", 500, HorizontalAlignment.Left)
lvShop.Columns.Add("Category", 100, HorizontalAlignment.Left)
lvShop.Columns.Add("Website", 170, HorizontalAlignment.Left)
lvShop.Columns.Add("Phone No", 100, HorizontalAlignment.Left)

在listview事件

Private Sub lvShop_ColumnClick(ByVal sender As Object, ByVal e As System.Windows.Forms.ColumnClickEventArgs) Handles lvShop.ColumnClick
     Dim new_sorting_column As ColumnHeader = lvShop.Columns(e.Column)
     Try
              ' Figure out the new sorting order.
              Dim sort_order As System.Windows.Forms.SortOrder
              If m_SortingColumn Is Nothing Then
                  ' New column. Sort ascending.
                  sort_order = SortOrder.Ascending
              Else
              ' See if this is the same column.
              If new_sorting_column.Equals(m_SortingColumn) Then
                  ' Same column. Switch the sort order.
                  If m_SortingColumn.Text.StartsWith("> ") Then
                      sort_order = SortOrder.Descending
                  Else
                      sort_order = SortOrder.Ascending
                  End If
              Else
                  ' New column. Sort ascending.
                  sort_order = SortOrder.Ascending
              End If
              ' Remove the old sort indicator.
              m_SortingColumn.Text = _
              m_SortingColumn.Text.Substring(2)
         End If
         ' Display the new sort order.
         m_SortingColumn = new_sorting_column
         If sort_order = SortOrder.Ascending Then
              m_SortingColumn.Text = "> " & m_SortingColumn.Text
         Else
              m_SortingColumn.Text = "< " & m_SortingColumn.Text
         End If
         ' Create a comparer.
         lvShop.ListViewItemSorter = New ListViewColumnSorter(e.Column, sort_order)
         ' Sort.
         lvShop.Sort()
     Catch ex As Exception
         strErrMsg = "Oops! Something is wrong with sorting column header."
         MessageBox.Show(strErrMsg & vbCrLf & "Err: " & ex.Message)
     End Try
End Sub

在项目中创建一个名为ListViewColumnSorter的新类复制并粘贴到班级。

Imports System.Collections
Imports System.Windows.Forms

Public Class ListViewColumnSorter
    Implements IComparer

    Private m_ColumnNumber As Integer
    Private m_SortOrder As SortOrder

    Public Sub New(ByVal column_number As Integer, ByVal _
        sort_order As SortOrder)
        m_ColumnNumber = column_number
        m_SortOrder = sort_order
    End Sub

    ' Compare the items in the appropriate column
    ' for objects x and y.
    Public Function Compare(ByVal x As Object, ByVal y As _
        Object) As Integer Implements _
        System.Collections.IComparer.Compare
        Dim item_x As ListViewItem = DirectCast(x,  _
            ListViewItem)
        Dim item_y As ListViewItem = DirectCast(y,  _
            ListViewItem)

        ' Get the sub-item values.
        Dim string_x As String
        If item_x.SubItems.Count <= m_ColumnNumber Then
            string_x = ""
        Else
            string_x = item_x.SubItems(m_ColumnNumber).Text
        End If

        Dim string_y As String
        If item_y.SubItems.Count <= m_ColumnNumber Then
            string_y = ""
        Else
            string_y = item_y.SubItems(m_ColumnNumber).Text
        End If

        ' Compare them.
        If m_SortOrder = SortOrder.Ascending Then
            If IsNumeric(string_x) And IsNumeric(string_y) _
                Then
                Return Val(string_x).CompareTo(Val(string_y))
            ElseIf IsDate(string_x) And IsDate(string_y) _
                Then
                Return DateTime.Parse(string_x).CompareTo(DateTime.Parse(string_y))
            Else
                Return String.Compare(string_x, string_y)
            End If
        Else
            If IsNumeric(string_x) And IsNumeric(string_y) _
                Then
                Return Val(string_y).CompareTo(Val(string_x))
            ElseIf IsDate(string_x) And IsDate(string_y) _
                Then
                Return DateTime.Parse(string_y).CompareTo(DateTime.Parse(string_x))
            Else
                Return String.Compare(string_y, string_x)
            End If
        End If
    End Function
End Class

此排序将对列表视图中的所有列进行排序。感谢互联网连接程序员：）

使用组合框排序列表视图

2 个答案: