DropDownList里的selectedIndexChange事件应怎样写呢？（DropDownList是从表里拿出一字段的值）

Question

    Public Sub DropDownList_changed(ByVal db_list As System.Object, ByVal e As System.EventArgs)
        ??????????????????
这里我要怎样写呢    End Sub

Answer 1

把DROPDOWNLIST的AUTOPOSTBACK设置成TRUE
你里面随便你怎么写
例如：if dropdownlist.selectedindex=2 then
end if
if dropdownlist.selectitem.text="hello" then
end if

Answer 2

string DD = DropDownList.SelectedIndexif DD == 2 then
  ....
end if

Answer 3

把DROPDOWNLIST的AUTOPOSTBACK设置成TRUE
你里面随便你怎么写
例如：if dropdownlist.selectedindex=多少then
end if

Answer 4

把DROPDOWNLIST的AUTOPOSTBACK设置成TRUE是在html代码页设吧？

Answer 5

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        '在此处放置初始化页的用户代码
        Dim db_list As New DataGrid()
        Try
            f_sConnection = oCS.GetConnectionString()
            f_SipDbConnection = New OleDbConnection(f_sConnection)
            If Not IsPostBack Then
                ShowTableList("1")            End If        Catch eLoad As System.Exception
            Me.Response.Write(eLoad.Message)
            f_SipDbConnection.Close()
        End Try    End Sub
    Private Sub ShowTableList(ByVal query_type As String)
        Dim view_name As String        If query_type = "1" Then
            sSqlString = "SELECT ASC_ID, AAC_NAME AS 广告商 FROM ADA_AAC_INFO_TABLE"
            view_name = "ADA_AAC_INFO_TABLE"        Else
            Exit Sub        End If        Try
            Dim dsDN As New DataSet()
            Dim sda_DN As New OleDbDataAdapter(sSqlString, f_SipDbConnection)
            dsDN.Clear()
            sda_DN.Fill(dsDN, view_name)
            If dsDN.Tables(view_name).Rows.Count > 0 Then
                DropDownList1.DataSource = dsDN.Tables(view_name).DefaultView
                DropDownList1.Visible = True
                DropDownList1.DataTextField = "AAC_NAME"
                DropDownList1.DataValueField = "ASC_ID"
                DropDownList1.SelectedIndex = 0
                DropDownList1.DataBind()                f_SipDbConnection.Close()
            Else
                Exit Sub
            End If        Catch eLoad As System.Exception
            Me.Response.Write(eLoad.Message)
            f_SipDbConnection.Close()        End Try
    End Sub    Public Sub DropDownList_changed(ByVal db_list As System.Object, ByVal e As System.EventArgs)        db_list.CurrentPageIndex = 0       
    End SubEnd Class帮我看看，这样写调试时没有东西出来？

Answer 6

private void DropDownList1_SelectedIndexChanged(object sender, System.EventArgs e) {
      string TCID=DropDownList1.SelectedValue.ToString().Trim();//取得字段
      string Conn= ConfigurationSettings.AppSettings.Get("Con");SqlConnection myconn=new SqlConnection(Conn);
string sql="select xxxx,xxxxxfrom ProductCategory where(TotalCategoryId='"+TCID+"')";
   DataTable DT=new DataTable();
  SqlDataAdapter SDA=new SqlDataAdapter(sql,myconn);
 SDA.Fill(DT);
                  
                               DropDownList2.DataSource=DT.DefaultView;
    DropDownList2.DataTextField="xxxxxx";      
    DropDownList2.DataValueField="xxxxxx";
    DropDownList2.DataBind();

我是用C#写的，由DropDownList1控制DropDownList2，将你数据库的字段赋值给DropDownList2.DataTextField和DropDownList2.DataValueField就ok了

Answer 7

Public Sub DropDownList_changed(ByVal db_list As System.Object, ByVal e As System.EventArgs)response.write(drop.selecteditem.value)
response.write(drop.selecteditem.text)    End Sub