根据其他DropDownList VB填充DropdownList [英] Populate DropdownList based upon other DropDownList VB

问题描述

我在互联网上找到了几个例子来做到这一点，但真的很努力地使其在VB中工作。 （试过一个转换器，但有不同的结果）

我需要根据第一个下拉列表中的不同值来填充一个下拉列表的选择选项。

任何人都可以在VB中帮助一个兼容性的简单例子？如果这些值在脚本中是硬编码的，那就不用担心。或者从表中提取数据的SQL位

提前感谢！

解决方案

完成的方式是在第一个下拉列表的SelectedIndexChanged事件中填充第二个下拉列表

示例：

 code> Protected Sub ddlCountry_SelectedIndexChanged（ByVal sender As Object，ByVal e As EventArgs）
 Dim CountryID As Integer = Convert.ToInt32（ddlCountry.SelectedValue.ToString（））
 FillStates（CountryID）
 End Sub 
 
 
 Private Sub FillStates（ByVal countryID As Integer）
 Dim strConn As String = ConfigurationManager.ConnectionStrings（DatabaseConnectionString）。ConnectionString 
 Dim con作为新的SqlConnection（strConn）
 Dim cmd As New SqlCommand（）
 cmd.Connection = con 
 cmd.CommandType = CommandType.Text 
 cmd.Command Text =Select StateID，State from State where CountryID = @ CountryID
 cmd.Parameters.AddWithValue（@ CountryID，countryID）
 Dim objD As New DataSet（）
 Dim dAdapter As新的SqlDataAdapter（）
 dAdapter.SelectCommand = cmd 
 con.Open（）
 dAdapter.Fill（objDs）
 con.Close（）
如果objDs.Tables 0）.Rows.Count> 0然后
 ddlState.DataSource = objDs.Tables（0）
 ddlState.DataTextField =State
 ddlState.DataValueField =StateID
 ddlState.DataBind（）
 ddlState.Items.Insert（0，--Select--）
 Else 
 lblMsg.Text =找不到状态
如果
 End Sub 
  

使用html源代码：

 < asp：DropDownList ID =ddlStaterunat =serverAutoPostBack =True> 
< / asp：DropDownList> 
 
< asp：DropDownList ID =ddlCountryrunat =server
 AutoPostBack =TrueOnSelectedIndexChanged =ddlCountry_SelectedIndexChanged> 
< / asp：DropDownList> 
  

I have found a couple of examples on the internet to do this but really struggling to get it working in VB. (Tried a converter but had mixed results)

I need the selection options of a Dropdownlist to be populated based upon the differing values in the first dropdown list.

Can anyone help with a releativley simple example in VB? Not fussed if the values are "hard coded" in the script. Or a SQL bit that pulls the data from a table

Thanks in advance!

解决方案

The way it is done is to populate second dropdown in SelectedIndexChanged event of the first dropdown

Example:

Protected Sub ddlCountry_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
    Dim CountryID As Integer = Convert.ToInt32(ddlCountry.SelectedValue.ToString())
    FillStates(CountryID)
End Sub


Private Sub FillStates(ByVal countryID As Integer)
  Dim strConn As String = ConfigurationManager.ConnectionStrings("DatabaseConnectionString").ConnectionString
  Dim con As New SqlConnection(strConn)
  Dim cmd As New SqlCommand()
  cmd.Connection = con
  cmd.CommandType = CommandType.Text
  cmd.CommandText = "Select StateID, State from State where CountryID =@CountryID"
  cmd.Parameters.AddWithValue("@CountryID", countryID)
  Dim objDs As New DataSet()
  Dim dAdapter As New SqlDataAdapter()
  dAdapter.SelectCommand = cmd
  con.Open()
  dAdapter.Fill(objDs)
  con.Close()
  If objDs.Tables(0).Rows.Count > 0 Then
    ddlState.DataSource = objDs.Tables(0)
    ddlState.DataTextField = "State"
    ddlState.DataValueField = "StateID"
    ddlState.DataBind()
    ddlState.Items.Insert(0, "--Select--")
  Else
    lblMsg.Text = "No states found"
  End If
 End Sub

With html source as so:

   <asp:DropDownList ID="ddlState" runat="server" AutoPostBack="True">
  </asp:DropDownList>

  <asp:DropDownList ID="ddlCountry" runat="server" 
  AutoPostBack="True" OnSelectedIndexChanged="ddlCountry_SelectedIndexChanged">
 </asp:DropDownList>

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