使用其他DropDown选择填充一个下拉列表 [英] Populating One Dropdownlist with selection of other DropDown

问题描述

我正在尝试使用其他DropDownlist控件选择填充一个下拉列表。

无法理解什么是错误的...因为没有发生任何事情，只是首先运行良好，即1号下拉是成功绑定数据但第二​​部分不起作用... PLZ帮助...

Hi, I am trying to Populating One Dropdownlist with selection of other DropDownlist control .
can't understand what is goin wrong..coz nothing is happening , just first is working well, i.e 1st Dropdown is binding data sucessfully but 2nd part isn't working...plz help...

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not IsPostBack Then
            cn.Open()
            boundDp()
            cn.Close()
        End If
End Sub

Public Sub boundDp()
        cmd.Connection = cn
        cmd.CommandText = "Select * From Acct_Sum"
        Dim da As New SqlDataAdapter(cmd)
        Dim dt As New DataTable
        da.Fill(dt)
        DPA1.DataSource = dt
        DPA1.DataTextField = "Loan_code"
        DPA1.DataValueField = "Loan_code"
        DPA1.DataBind()
        DPA1.Items.Insert(0, "Select Item Here")
End Sub

Public Sub Shw_data()
        cmd.Connection = cn
        cmd.CommandText = "Select * From Acct_Sum Where Loan_code=@Loan_code"
        cmd.Parameters.AddWithValue("@Loan_code", DPA1.SelectedItem.Value)
        Dim dr As SqlDataReader
        dr = cmd.ExecuteReader
        If dr.HasRows Then
            dr.Read()
            TextBox1.Text = dr.Item("Bor_Name").ToString
            TextBox2.Text = dr.Item("coBor_Name").ToString
        End If
End Sub

Public Sub shw_data2()
        cmd.Connection = cn
        cmd.CommandText = "Select Loan_code From Acct_Sum2 Where Loan_code=@Loan_code"
        cmd.Parameters.AddWithValue("@Loan_code", DPA2.SelectedItem.Value)
        Dim da As New SqlDataAdapter(cmd)
        Dim dt As New DataTable
        da.Fill(dt)
        DPA2.DataSource = dt
        'DPA2.DataTextField = "chk_Num"
        DPA2.DataValueField = "Loan_code"
        DPA2.DataBind()
        DPA2.Items.Insert(0, "Select Sub Item")
End Sub

Private Sub DPA2_SelectedIndexChanged(sender As Object, e As EventArgs) Handles DPA2.SelectedIndexChanged
        cn.Open()
       
        shw_data2()
        cn.Close()
End Sub

注意......我有两个表... Acct_Sum和Acct_Sum2，唯一ID = Loan_code



Thnx ....

Note...I have two tables...Acct_Sum and Acct_Sum2 with Unique ID=Loan_code

Thnx....

推荐答案

按照下面的代码我做了一些修改来制作它更容易和工作。我没有验证连接等。



1）定义下面的两个下拉列表

Follow the code below i have made some modifications to make it easier and work. I didnt verified connections etc.

1) Define two dropdown list like below

<asp:dropdownlist id="drp1" runat="server" onselectedindexchanged="drp1_SelectedIndexChanged" autopostback="true" datavaluefield="xyz" datatextfield="xyz" xmlns:asp="#unknown">
</asp:dropdownlist>
<asp:dropdownlist id="drp2" runat="server" datavaluefield="loan_code" datatextfield="loan_code" xmlns:asp="#unknown">    
</asp:dropdownlist>

2）

2)

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Not IsPostBack Then
            cn.Open()
            boundDp()
            cn.Close()
        End If
End Sub

3）

3)

Public Sub boundDp()
        cmd.Connection = cn
        cmd.CommandText = "Select xyz From Acct_Sum"
        Dim da As New SqlDataAdapter(cmd)
        Dim dt As New DataTable
        da.Fill(dt)            
        Dim dr As DataRow = dt.NewRow()
        dr("xyz") = "Select Item Here"
        dt.Rows.InsertAt(dr, 0)
        drp1.DataSource = dt 
        drp1.DataBind()        
End Sub

4）

4)

Private Sub drp1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles DPA2.SelectedIndexChanged
        cn.Open()       
        cmd.Connection = cn
        cmd.CommandText = "Select loan_code From Acct_Sum2 Where loan_code=@Loan_code"
        cmd.Parameters.AddWithValue("@Loan_code", drp1.SelectedValue)
        Dim da As New SqlDataAdapter(cmd)
        Dim dt As New DataTable
        da.Fill(dt)
        Dim dr As DataRow = dt.NewRow()
        dr("xyz") = "Select Sub Item Here"
        dt.Rows.InsertAt(dr, 0)
        drp2.DataSource = dt        
        drp2.DataBind()
        cn.Close() 
End Sub

问候..：笑：

Regards..:laugh:

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