從其他組合框的選定項目填充組合框

我正在創建一個窗體，其中用戶必須提供州名和城市名稱。城市依賴於國家。從其他組合框的選定項目填充組合框

代碼用於填充城市：

Dim ds As DataSet = New DataSet 
Dim adapter As New OleDb.OleDbDataAdapter 
Dim sql As String 
    sql = "SELECT * from statestab order by `state` ASC;" 
    adapter.SelectCommand = New OleDb.OleDbCommand(sql, con) 
    adapter.Fill(ds) 
    ComboBoxstate.DataSource = ds.Tables(0) 
    ComboBoxstate.ValueMember = "stateid" 
    ComboBoxstate.DisplayMember = "state"

代碼爲城市：

Dim ds As DataSet = New DataSet 
Dim adapter As New OleDb.OleDbDataAdapter 
Dim sql As String 
Dim st As Integer 
    st = ComboBoxstate.SelectedValue.ToString() 
    sql = "SELECT * from citytab where stateid=st order by `cityname` ASC;" 
    adapter.SelectCommand = New OleDb.OleDbCommand(sql, con) 
    adapter.Fill(ds) 
    citycombo.DataSource = ds.Tables(0) 
    citycombo.ValueMember = "cityid" 
    citycombo.DisplayMember = "cityname"

在下拉列表中，當選擇城市化，我撥打市加載功能來填充城市組合框。但我無法填充城市組合框。

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2015-03-25 govinda sinha

什麼不工作？你得到一個錯誤或國家不顯示？ – phil652 2015-03-25 12:18:20

它看起來像你沒有將狀態ID傳入你的第二個查詢中，而只是文本「st」而不是「st」變量的值。除非你在表中有一個名爲'st'的列，否則我希望你看到一個SQL異常？ – 2015-03-25 12:39:41

我有一個列名稱stateid城市選項卡，這也是目前statestab – 2015-03-25 16:53:02

您需要在狀態組合框中的Selected_Index_Changed中使用處理程序。從那裏，叫你的日常裝載了城，在SQL的城市，你需要做的

where stateid=" & comboBox1.SelectedValue.ToString()

來源

2015-03-25 13:35:15 AAzami

嘗試過但不工作， – 2015-03-25 16:53:25

以下是全文，請注意，是可以要好得多，但我試圖保持你的語法機智：

Private Sub cboState_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cboState.SelectedIndexChanged 
    Load_Cities() 

End Sub 

Private Sub Load_States() 
    Dim ds As DataSet = New DataSet 
    Dim adapter As New OleDb.OleDbDataAdapter 
    Dim sql As String 
    sql = "SELECT * from tblState order by StateName ASC;" 
    adapter.SelectCommand = New OleDb.OleDbCommand(sql, con) 
    adapter.Fill(ds) 
    cboState.DataSource = ds.Tables(0) 
    cboState.ValueMember = "stateid" 
    cboState.DisplayMember = "statename" 
End Sub 

Private Sub Load_Cities() 
    On Error Resume Next 

    Dim ds As DataSet = New DataSet 
    Dim adapter As New OleDb.OleDbDataAdapter 
    Dim sql As String 
    sql = "SELECT * from tblCity where StateID = " & cboState.SelectedValue.ToString() & " order by CityName ASC;" 
    adapter.SelectCommand = New OleDb.OleDbCommand(sql, con) 
    adapter.Fill(ds) 
    cboCity.DataSource = ds.Tables(0) 
    cboCity.ValueMember = "CityID" 
    cboCity.DisplayMember = "CityName" 



End Sub

來源

2015-03-27 19:57:40 AAzami

謝謝我添加StateID =「＆cboState.SelectedValue.ToString（）這到我的代碼，它是像魅力 – 2015-03-29 15:36:29

從其他組合框的選定項目填充組合框

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