Question

这是在以前解析的与组合框中的Access数据库值相关的查询的延续。下面的代码工作正常。即，它将Access表列中的数据导入到组合框的下拉列表中。我想要的是如何根据Combobox.SelectedIndex分配这些值？我添加了TagComboBox1.SelectedIndex = 0，但我想要一些会自动为索引到组合框下拉列表中填充的值的内容。源表是tag_data＆＃39; 键列是tag_unique_id

我需要它，因为我想使用combobox.selectedindexchanged事件来执行更多任务。我玩了但没有成功。

Dim dt As New DataTable
Dim query As String = "select tag_unique_id from tag_data order by tag_unique_id"
Using connection As New OleDbConnection(strConnectionString)
    Using command As New OleDbCommand(query, connection)
        Using adapter As New OleDbDataAdapter(command)
            connection.Open()
            adapter.Fill(dt)
            connection.Close()
        End Using
    End Using
End Using
If dt.Rows.Count > 0 Then
    TagComboBox1.DataSource = dt
    TagComboBox1.ValueMember = "tag_unique_id"
    TagComboBox1.DisplayMember = "tag_unique_id"
    TagComboBox1.SelectedIndex = 0
End If

更新：以下是combobox.selectedindexchanged代码。在项目工作期间，索引可以是任何内容，因此我可以使用一个变量来为selectedindexchanged事件指定新值，而不是指定为selectedindex=0 (1,2,3..)吗？

 Private Sub TagComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As system.EventArgs) Handles TagComboBox1.SelectedIndexChanged
'reference http://stackoverflow.com/questions/13152534/view-data-from-database-using-textbox
Dim dt As New DataTable
Dim query As String = "select tag_text from tag_data"
Dim dr As OleDbDataReader
Dim connection As New OleDbConnection(strConnectionString)
Dim command As New OleDbCommand(query, connection)
connection.Open()
If TagComboBox1.SelectedIndex = 0 Then

    dr = command.ExecuteReader
    While dr.Read()
        TagTextBox.Text = dr("tag_text").ToString
    End While
    dr.Close()

End If

Answer 1

如果您尝试根据组合框的选定索引填充文本框，则需要执行此操作。

For index As Integer = 0 To (ComboBox1.Items.Count - 1)
        textbox.Text = ComboBox1.Items(index)
    Next

如何循环组合框中提取的MS Access表列值（VB .Net）

1 个答案: