Question

我的目标是使用多个文本框开发搜索。我有五列（ArticleNo，Description，PartNum，制造商和成本），每列都有一个文本框。

我使用以下方式跟踪原始列表项：

Private originalListItems As New List(Of ListViewItem)

这包含所有项目（超过6000）。

然后我会根据创建的五个文本框（tbSearchArticleNo，tbSearchDescription，tbSearchPartNum ...等）发生五个“文本更改”事件

Private Sub tbSearchArticleNo_TextChanged(sender As Object, e As System.EventArgs) Handles tbSearchArticleNo.TextChanged
    If tbSearchDesc.Text <> "" Or tbPartNum.Text <> "" Or tbManufacturer.Text <> "" Or tbCost.Text <> "" Then
        SearchCurrentList(lwArticles, tbSearchArticleNo.Text, 0, False)
    Else
        SearchListView(lwArticles, tbSearchArticleNo.Text, 0, False)
    End If
End Sub

这是我的方法SearchCurrentList：

Private Sub SearchCurrentList(ByVal listview As ListView, ByVal search As String, ByVal colIndex As Integer, ByVal upperCase As Boolean)
    If upperCase Then
        search = search.ToUpper()
    End If

    listview.BeginUpdate()

    'Clear listview
    lwArticles.Items.Clear()

    'Other textbox has information in it, concatenate both results
    For Each item In currentListItems
        Dim itemToUpper = item.SubItems.Item(colIndex).Text
        If upperCase Then
            itemToUpper = item.SubItems.Item(colIndex).Text.ToUpper()
        End If
        If itemToUpper.Contains(search) Then
            lwArticles.Items.Add(item)
        End If
    Next

    'Reupdate the current list of items
    currentListItems.Clear()
    For Each item In lwArticles.Items
        currentListItems.Add(item)
    Next

    listview.EndUpdate()
End Sub

这是我的方法SearchListView：

Private Sub SearchListView(ByVal listview As ListView, ByVal search As String, ByVal colIndex As Integer, ByVal upperCase As Boolean)
    'Upper case parameter determines if you're searching a string, if so, it is better to compare everything by uppercase
    If upperCase Then
        search = search.ToUpper()
    End If

    listview.BeginUpdate()

    If search.Trim().Length = 0 Then
        'Clear listview
        listview.Items.Clear()

        'Clear currentListItems
        currentListItems.Clear()

        'If nothing is in the textbox make all items appear
        For Each item In originalListItems
            listview.Items.Add(item)
        Next

    Else
        'Clear listview
        listview.Items.Clear()

        'Clear currentListItems
        currentListItems.Clear()

        'Go through each item in the original list and only add the ones which contain the search text
        For Each item In originalListItems
            Dim currItem = item.SubItems.Item(colIndex).Text
            If upperCase Then
                currItem = currItem.ToUpper()
            End If
            If currItem.Contains(search) Then
                currentListItems.Add(item)
                listview.Items.Add(item)
            End If
        Next
    End If

    listview.EndUpdate()
End Sub

以下是我的搜索示例：

tbSearchArticleNo.Text =“33”

这将匹配字符串中包含“33”的每篇文章。现在我想添加另一个过滤器：

tbSearchDescription.Text =“混音器”

这应匹配商品编号中包含33的所有内容以及说明中的“调音台”。等等等等。第四。

实际过滤器工作正常 - 我唯一的问题是每当我擦除某些内容时，例如“Mixer”（在文章中仍然有“33”）它不会返回包含“33”的articleNo的结果。 ..相反，它不会改变我的搜索结果。可能有更好的搜索方式吗？

Answer 1

不是一次只过滤一列并传递当前列表以进一步过滤结果，而是让一个函数同时根据所有指定值进行过滤：

从每个过滤器文本框的TextChanged（或Validated）事件中调用单个“过滤器”函数。
在Filter函数中，首先将originalListItems重新复制到lwArticles。
为每个具有序列值的文本框应用过滤器。（为每个文本框调用SearchCurrentList，传入lwArticles。每个步骤都会过滤掉前一个列表，但只对具有值的文本框进行处理。）

Answer 2

很难理解你想要做的事情，但我建议如果你在列表视图中处理6k项目并想要过滤它们，也许你应该使用数据绑定gridview代替。

然后，您可以非常简单地在数据源上执行搜索：

Public Class Form1
Private _articleList As List(Of Article)

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    'populate _itemList somehow, for example from a database. Manually here for example purposes:
    _articleList = New List(Of Article) From {
        New Article("jenny cooks fish", "cooking"),
        New Article("a better sales team", "sales")}
    DataGridView1.DataSource = _articleList
End Sub


Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim filtered As List(Of Article) = _articleList.Where(Function(x) x.Title.Contains("cook") AndAlso x.Category = "cooking").ToList
    DataGridView1.DataSource = filtered

End Sub
End Class

Public Class Article
Property Title As String
Property Category As String
'etc etc

Public Sub New(ByVal title As String, ByVal category As String)
    _Title = title
    _Category = category
End Sub
End Class

Answer 3

处理此问题的一种不同方式是使用LINQ。以下函数可用于返回枚举提供的集合的对象，仅包括适合过滤器的项目。您可以使用此枚举器重新填充列表。如果您每次调用GetFilter时都使用了originalListItems，那么您将始终在最新的过滤器中包含所有项目以供考虑。

Function GetFilter(source As IEnumerable(Of ListViewItem), articleNo As String, description As String,
                  partNum As String, prop4 As String, prop5 As String) As IQueryable(Of ListViewItem)
  GetFilter = source.AsQueryable

  Dim articleFilter As Expressions.Expression(Of Func(Of ListViewItem, Boolean)) = _
     Function(i As ListViewItem) i.SubItems(0).Text.IndexOf(articleNo, StringComparison.InvariantCultureIgnoreCase) >= 0
  Dim descFilter As Expressions.Expression(Of Func(Of ListViewItem, Boolean)) = _
     Function(i As ListViewItem) i.SubItems(1).Text.IndexOf(description, StringComparison.InvariantCultureIgnoreCase) >= 0
  Dim partFilter As Expressions.Expression(Of Func(Of ListViewItem, Boolean)) = _
     Function(i As ListViewItem) i.SubItems(2).Text.IndexOf(partNum, StringComparison.InvariantCultureIgnoreCase) >= 0
  Dim prop4Filter As Expressions.Expression(Of Func(Of ListViewItem, Boolean)) = _
     Function(i As ListViewItem) i.SubItems(3).Text.IndexOf(prop4, StringComparison.InvariantCultureIgnoreCase) >= 0
  Dim prop5Filter As Expressions.Expression(Of Func(Of ListViewItem, Boolean)) = _
     Function(i As ListViewItem) i.SubItems(4).Text.IndexOf(prop5, StringComparison.InvariantCultureIgnoreCase) >= 0

  If Not String.IsNullOrEmpty(articleNo) Then GetFilter = Queryable.Where(GetFilter, articleFilter)
  If Not String.IsNullOrEmpty(description) Then GetFilter = Queryable.Where(GetFilter, descFilter)
  If Not String.IsNullOrEmpty(partNum) Then GetFilter = Queryable.Where(GetFilter, partFilter)
  If Not String.IsNullOrEmpty(prop4) Then GetFilter = Queryable.Where(GetFilter, prop4Filter)
  If Not String.IsNullOrEmpty(prop5) Then GetFilter = Queryable.Where(GetFilter, prop5Filter)
End Function

更好的是，稍微考虑一下，你可以将articleNo和其他参数变成具有更大范围的变量，并调整函数以将IsNullOrEmpty检查嵌入到Queryable表达式中，然后你就不需要字段值更改时重新生成过滤器。您可以将变量设置为新的文本框值并重新评估已生成的过滤器表达式，该表达式将考虑变量中的新值，从而产生新过滤的结果。

以下是我期望它的使用方式：

lwArticles.Items.Clear()
For Each i In GetFilter(originalListItems, tbSearchArticleNo.Text, tbSearchDesc.Text, tbPartNum.Text, tbManufacturer.Text, tbCost.Text)
   lwArticles.Items.Add(i)
Next

Answer 4

我设法让它发挥作用。对于那些想知道怎么样的人来说，它并不那么优雅 - 但它确实有效！

我在四个文本框的GUI上设置了标签（在与工程师进一步交谈后，我省略了成本文本框）。所以..

tbSearchArticleNo.Tag = 1

tbSearchDesc.Tag = 2

tbPartNum.Tag = 4

tbManufacturer.Tag = 8

这并不优雅，因为在添加文本框时，指数会逐渐增长。（注意）根据输入的字段，计算总数，然后由我的FilterOriginalList（总计）处理

Private Sub tbSearchArticleNo_TextChanged(sender As Object, e As System.EventArgs) Handles tbSearchArticleNo.TextChanged, tbSearchDesc.TextChanged, tbPartNum.TextChanged, tbManufacturer.TextChanged
    Dim tag1 As Integer = 0
    Dim tag2 As Integer = 0
    Dim tag3 As Integer = 0
    Dim tag4 As Integer = 0

    If tbSearchArticleNo.Text <> "" Then
        tag1 = tbSearchArticleNo.Tag
    End If

    If tbSearchDesc.Text <> "" Then
        tag2 = tbSearchDesc.Tag
    End If

    If tbPartNum.Text <> "" Then
        tag3 = tbPartNum.Tag
    End If

    If tbManufacturer.Text <> "" Then
        tag4 = tbManufacturer.Tag
    End If

    FilterOriginalList(tag1 + tag2 + tag3 + tag4)
End Sub

这是我的方法：

Private Sub FilterOriginalList(ByRef tagCounter As Integer)
    Dim field1 As String = tbSearchArticleNo.Text
    Dim field2 As String = tbSearchDesc.Text.ToUpper()
    Dim field4 As String = tbPartNum.Text.ToUpper()
    Dim field8 As String = tbManufacturer.Text.ToUpper()

    lwArticles.BeginUpdate()

    'Clear listview
    lwArticles.Items.Clear()

    For Each item In originalListItems
        Dim currField1 = item.SubItems.Item(0).Text
        Dim currField2 = item.SubItems.Item(1).Text.ToUpper
        Dim currField4 = item.SubItems.Item(2).Text.ToUpper
        Dim currField8 = item.SubItems.Item(3).Text.ToUpper

        Select Case (tagCounter)
            Case 0
                lwArticles.Items.Add(item)
            Case 1
                If currField1.Contains(field1) Then
                    lwArticles.Items.Add(item)
                End If
            Case 2
                If currField2.Contains(field2) Then
                    lwArticles.Items.Add(item)
                End If
            Case 3
                If currField1.Contains(field1) And currField2.Contains(field2) Then
                    lwArticles.Items.Add(item)
                End If
            Case 4
                If currField4.Contains(field4) Then
                    lwArticles.Items.Add(item)
                End If
            Case 5
                If currField1.Contains(field1) And currField4.Contains(field4) Then
                    lwArticles.Items.Add(item)
                End If
            Case 6
                If currField2.Contains(field2) And currField4.Contains(field4) Then
                    lwArticles.Items.Add(item)
                End If
            Case 7
                If currField1.Contains(field1) And currField2.Contains(field2) And currField4.Contains(field4) Then
                    lwArticles.Items.Add(item)
                End If
            Case 8
                If currField8.Contains(field8) Then
                    lwArticles.Items.Add(item)
                End If
            Case 9
                If currField1.Contains(field1) And currField8.Contains(field8) Then
                    lwArticles.Items.Add(item)
                End If
            Case 10
                If currField2.Contains(field2) And currField8.Contains(field8) Then
                    lwArticles.Items.Add(item)
                End If
            Case 11
                If currField1.Contains(field1) And currField2.Contains(field2) And currField8.Contains(field8) Then
                    lwArticles.Items.Add(item)
                End If
            Case 12
                If currField4.Contains(field4) And currField8.Contains(field8) Then
                    lwArticles.Items.Add(item)
                End If
            Case 13
                If currField1.Contains(field1) And currField4.Contains(field4) And currField8.Contains(field8) Then
                    lwArticles.Items.Add(item)
                End If
            Case 14
                If currField2.Contains(field2) And currField4.Contains(field4) And currField8.Contains(field8) Then
                    lwArticles.Items.Add(item)
                End If
            Case 15
                If currField1.Contains(field1) And currField2.Contains(field2) And currField4.Contains(field4) And currField8.Contains(field8) Then
                    lwArticles.Items.Add(item)
                End If
        End Select
    Next
    lwArticles.EndUpdate()
End Sub

感谢所有帮助过的人。这是我找到的解决方案 - 我可能会在未来中看到更容易的东西！

VB.NET Listview多列过滤器

4 个答案: