如何通过更改VB.Net中的组合框中的项目从Access 2007数据库填充列表框 [英] How to Populate a Listbox from Access 2007 database by changing items from Combo Box in VB.Net

问题描述

亲爱的所有

我只是在VB.Net和Access 2007中开发一个项目，我只是陷入了我只需要从Access 2007数据库填充列表框但我改变了组合框中的项目列表框应相应更改。我有填充列表框的代码但更改组合框项目后项目没有变化。

请指导我这方面。

Dear all
I am just developing a project in VB.Net and Access 2007 and i just got stuck at a point where I just need to Populate a Listbox from Access 2007 database but if I change an item from the combo box the listbox should change accordingly. I have the code to populate the listbox but items are not changing after changing combo box items.
Please guide me in this regard.

Private Sub frmneworder_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        cmbmain.Text = "Select Main Item"
        Call loadinvestigations()
    End Sub

Sub loadinvestigations()
        Con.Open()
        Dim cmd As New OleDbCommand("select * from items", Con)
        Dim dr As OleDbDataReader = cmd.ExecuteReader
        While dr.Read
            lstitem.Items.Add(dr(1).ToString.ToUpper)
        End While
        dr.Close()
        Con.Close()

Private Sub cmbmain_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbmain.SelectedIndexChanged
       Con.Open()
       Dim cmd As New OleDbCommand("select item_name from items where cat_name='" & txtopd.Text & "'", Con)
       Dim dr As OleDbDataReader = cmd.ExecuteReader()
       While dr.Read
           lstitem.Items.Add(dr(1).ToString.ToUpper)
       End While
       dr.Close()
       Con.Close()
   End Sub

推荐答案

大家好，最后用以下代码工作：

Hello guys It worked finally with the following code:

Private Sub cmbmain_SelectedValueChanged(sender As Object, e As EventArgs) Handles cmbmain.SelectedValueChanged
        lstitem.Items.Clear()
        Con.Open()
        Dim cmd As New OleDbCommand("select * from items where cat_name='" & cmbmain.Text & "'", Con)
        Dim dr As OleDbDataReader = cmd.ExecuteReader
        While dr.Read
            lstitem.Items.Add(dr(1).ToString.ToUpper)
        End While
        dr.Close()
        Con.Close()
    End Sub

我感谢Mt Maciej Los的帮助。

谢谢

I thank Mt Maciej Los for his kind help.
Thank you

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