使用来自第一个组合框和逗号分隔文件的数据填充第二个组合框

Question

我有一个组合框，可以从逗号分隔的文件中获取不同的数据。 我需要使用该不同的数据并填充第二个组合框，其中仅包含有关第一个组合框的信息。 例子： 这是我用逗号分隔的文件文本。

Jenny, 25, Female
Micheal, 100, Female, hdfgh
shaun, 50, male
Cindy, 75, Female
Jenny, 25, Female
Micheal, 100, Female
shaun, 50, male
Cindy, 50, Female
Carry, 75, Female

这是我的代码：

Public Class Form1

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Call combo1()
    Call combo2()
End Sub

Sub combo1()
    ' a set to store the names
    Dim names = New HashSet(Of String)
    Using reader = New Microsoft.VisualBasic.FileIO.TextFieldParser("C:\here.txt")

        reader.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
        reader.Delimiters = New String() {","}
        Dim currentRow As String()
        While Not reader.EndOfData
            Try
                ' read rows and add first field to set
                currentRow = reader.ReadFields()
                names.Add(currentRow(0).ToString())
            Catch ex As Microsoft.VisualBasic.FileIO.MalformedLineException
                ' do something
            End Try
        End While
    End Using

    ' bind data to combo box (or use Items.Add instead)
    ComboBox1.DataSource = names.ToList()
End Sub

Sub combo2()
    ' a set to store the names
    Dim names = New HashSet(Of String)
    Using reader = New Microsoft.VisualBasic.FileIO.TextFieldParser("C:\here.txt")

        reader.TextFieldType = Microsoft.VisualBasic.FileIO.FieldType.Delimited
        reader.Delimiters = New String() {","}
        Dim currentRow As String()
        While Not reader.EndOfData
            Try
                ' read rows and add first field to set
                currentRow = reader.ReadFields()
                names.Add(currentRow(1).ToString())
            Catch ex As Microsoft.VisualBasic.FileIO.MalformedLineException
                ' do something
            End Try
        End While
    End Using

    ' bind data to combo box (or use Items.Add instead)
    ComboBox2.DataSource = names.ToList()
End Sub

这可以很好地将不同的数据填充到每个组合框中，但我希望第二个组合框仅填充来自组合框 1 中所选项目的数据，例如，如果我选择 “Cindy”下一个组合框必须只显示 25 和 75 而不是所有不同的结果

Answer 1

按照您的方式绑定第一个组合框。捕获组合框SelectedValueChanged 事件。 使用SelectedValue 属性，对文件进行第二次传递。这次将值添加到不同的哈希集中，如下所示：

Dim ages = New HashSet(Of String)
    Using reader = New Microsoft.Visua...   ...FieldParser("C:\here.txt")

        reader.TextFieldType = Micros...   ....eldType.Delimited
        reader.Delimiters = New String() {","}
        Dim currentRow As String()
        While Not reader.EndOfData
            Try
                '   v--- THIS LINE IS IMPORTANT ---v
                if currentRow(0).ToString() = combobox1.selectedvalue then

                    ages.Add(currentRow(1).ToString())
                end if

你懂的

    ' bind data to combo box (or use Items.Add instead)
    ComboBox2.DataSource = ages.ToList()

在ComboBox2SelectedValueChanged写接受码