Using placeholders to display multiple dropdowns which are related from table data [Answered]RSS

• • Reply
  heron6

  Member

  1 Points

  29 Posts

  Using placeholders to display multiple dropdowns which are related from table data

  May 06, 2014 12:13 PM|heron6|LINK

  Hi there,

  I currently have a table in the database which i use to display dropdowns, i am currrently trying to create a interface to manage this table in the same format which it is displayed within my application.

  So i have a table with 3 main columns, ID, CLIENT ID and ParentID, I want to be able to show a dropdown menu which then can drill down each level within the table to show its related parentIDS. So in the first case i want the first dropdown to select columns with a parentid of 0 or NULL from when the user selects this it will show the next dropdown menu which will show all parentids of the first selected ID which the relationship is. For example (dropdown 1 - ID = 1 ParentID = 0) then (dropdown 2 ID- WHATEVER and ParentID = ID of Dropdown1) and this can go on and on and on for other dropdowns till there is no relationship. I want to be able to add a row to the table so need to get the ID of the dropdown menus. I will be looking to create, add, delete and updates for these rows so after a dropdown is displayed i will be showing a 'add' / edit link next to each dropdown which will then show a panel with text boxs to add to or edit.  I am having trouble finding the control for the dropdown so i can get the value, can anyone help? and if so does anyone else have any useful posts i can relate to, which will help me create what i am looking to do? (Some code below) And if i aint taking the right approach if you could point me in the correct direction that would be great, this is my first time attemping something like this so any guidance will be great.

  Thanks

      Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
  
          If ControlCount <> 0 Then
              RecreateControls()
          End If
  
          If Not Page.IsPostBack Then
  
  
              Button_Delete.Attributes.Add("onclick", "return confirm('Are you sure you want to delete this user ?');")
  
          End If
  
      End Sub
    Private Property ControlCount As Int32
          Get
              If ViewState("ControlCount") Is Nothing Then
                  ViewState("ControlCount") = 0
              End If
              Return DirectCast(ViewState("ControlCount"), Int32)
          End Get
          Set(ByVal value As Int32)
              ViewState("ControlCount") = value
          End Set
      End Property
  
  
  
      Private Sub RecreateControls()
          addControls(ControlCount)
      End Sub
  
      Private Sub addControls(ByVal count As Int32)
          For i As Int32 = 1 To count
              ' Dim btn As New DropDownList() ' i use a Button as example'
              ' btn.ID = "Button_" & Me.Container.Controls.Count
              'btn.Text = "Button " & Me.Container.Controls.Count
              Dim tCaseConfig As DataTable = tools.ClientCaseConfig(Session("ClientID"))
              Dim v As New DataView
  
  
              v.Table = tCaseConfig
              'If count = 1 Then
              '    v.RowFilter = "ccParentID ='0' OR ccParentID = NULL"
              'Else
              '    ' v.RowFilter = "ccParentID = " & FindControl("DropDownList2")
              'End If
  
              If count = 1 Then
  
                  v.RowFilter = "ccParentID ='0' OR ccParentID = NULL"
                  Dim DropDownList1 As New DropDownList()
                  With DropDownList1
                      .DataSource = v.ToTable(True, "ccNAME", "ccID")
                      .DataTextField = "ccNAME"
                      .DataValueField = "ccID"
                      .DataBind()
                      .AutoPostBack = True
                      _ui.ControlBuilder_DropDownList_AddRow(DropDownList1, "select...", 0, False, True)
                  End With
  
                  AddHandler DropDownList1.SelectedIndexChanged, AddressOf DdlAddControls1_SelectedIndexChanged
                  Me.PlaceHolder1.Controls.Add(DropDownList1)
  
                  'Session("SESSION") = 911
                  ' Dim Value As DropDownList = ("DropDownList1").
  
                  'Dim Value As String = FindControl("DropDownList1").SkinID;eee
                  'DropDownList1.Text = Session("SESSION")
                  'Dim Value As String = PlaceHolder1.Page.FindControl("DropDownList1").ToString
                  'Session("SESSION") = Value
              End If
          Next
      End Sub
  
      Private Sub Click(ByVal sender As Object, ByVal e As EventArgs)
          ' LblInfo.Text = DirectCast(sender, Button).Id & "clicked"
      End Sub
  
      Protected Sub DdlAddControls_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList_Clients.SelectedIndexChanged
          'Dim newControlCount As Int32 = Int32.Parse(DropDownList_Clients.SelectedValue)
          Dim newControlCount As Int32 = 1
          addControls(newControlCount)
          ControlCount += newControlCount
  
      End Sub
  
      Protected Sub DdlAddControls1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs)
          'Dim newControlCount As Int32 = Int32.Parse(DropDownList_Clients.SelectedValue)
          ' Session("SESSION") = Me.drop
          ' Dim DropDownLIST = DirectCast(sender, "DropDownList1")
          'Session("SESSION1") = DirectCast(item.FindControl("DropDownList1"), System.Web.UI.WebControls.DropDownList)
          Dim newControlCount As Int32 = 1
          addControls(newControlCount)
          ControlCount += newControlCount
  
          Dim tCaseConfig As DataTable = tools.ClientCaseConfig(Session("ClientID"))
          Dim v As New DataView
  
  
          v.Table = tCaseConfig
  
  
          'v.RowFilter = "ccParentID=" & Session("SESSION1")
          ' v.RowFilter = "ccParentID=" & PlaceHolder1.FindControl("DropDownList1")
          Dim DropDownList2 As New DropDownList()
          With DropDownList2
              .DataSource = v.ToTable(True, "ccNAME", "ccID")
              .DataTextField = "ccNAME"
              .DataValueField = "ccID"
              .DataBind()
              .AutoPostBack = True
              _ui.ControlBuilder_DropDownList_AddRow(DropDownList2, "select...", 0, False, True)
          End With
  
          AddHandler DropDownList2.SelectedIndexChanged, AddressOf DdlAddControls1_SelectedIndexChanged
          Me.PlaceHolder1.Controls.Add(DropDownList2)
  
      End Sub

  vb placeholder vb.net dropdownlist binding

• • Reply
  heron6

  Member

  1 Points

  29 Posts

  Re: Using placeholders to display multiple dropdowns which are related from table data

  May 07, 2014 04:35 AM|heron6|LINK

  Is anyone able to help?

• • Reply
  Fuxiang Zhan...

  All-Star

  30411 Points

  3628 Posts

  Re: Using placeholders to display multiple dropdowns which are related from table data

  May 07, 2014 06:23 AM|Fuxiang Zhang - MSFT|LINK

  Hi heron6,

  Thank you post the issue to our forum.

  According to your descriptioin, I see you want to complete the multiple cascade dropdownlists in asp.net.

  For this issue, I suggest you using the Ajax to do that like below demo made for your issue.

  <head runat="server">
      <title></title>
      <script src="//code.jquery.com/jquery-1.10.2.js"></script>
      <script>
          var order = 0;
          function CreateDropdownlist(parentId)
          {   
              $.ajax({
                  type: "Post", 
                  contentType: "application/json", 
                  url: "MultipleCascadeDropDown.aspx/DDLKeyAndValue",
                  data: "{ParentID:'" + parentId + "'}",
                  dataType: 'Json',
                  success: function (result) {
                     
                      var data = eval(result.d);
                      var s = $('<select order="' + order + '" onchange="GetChildDropDown(this)" />');
                      $('<option />', { value: "", text:"Select...." }).appendTo(s);
                      $.each(data, function (index, element) {
  
                          $('<option />', { value: data[index].Key, text: data[index].Value }).appendTo(s);
                      });  
                      s.appendTo('#DropdownlistContainer'); 
                      order++;
                     
                  }
              });
           
  
          }
          //add children dropdownlist
          function GetChildDropDown(e) { 
              if ($(e).val() != "") { 
                  RemoveDoprdown($(e).attr("order"));
                  CreateDropdownlist($(e).val());
              }
          }
          //remove children dropdownlist
          function RemoveDoprdown(myorder) {
            
              $("#DropdownlistContainer").find("select").each(function () {
                  
                  if (parseInt($(this).attr("order")) > parseInt(myorder)) {
                      $(this).remove(); 
                      order--;
                  }
              });
          }
          //add the first dropdownlist
          CreateDropdownlist(0);
      </script>
  </head>
  <body>
      <form id="form1" runat="server">
      <div id="DropdownlistContainer">  
      </div>
      </form>
  </body>

  code behind:

    public static DataTable testdata = null;
          protected void Page_Load(object sender, EventArgs e)
          {
              if (!IsPostBack) {
                  //test data suppose comes from database
                  testdata = new DataTable();
                  testdata.Columns.Add("ID");
                  testdata.Columns.Add("Value");
                  testdata.Columns.Add("ParentID");
                  testdata.Rows.Add(1,"1",0);
                  testdata.Rows.Add(2, "2", 0);
                  testdata.Rows.Add(3, "3", 1);
                  testdata.Rows.Add(4, "4", 1);
                  testdata.Rows.Add(5, "5", 2);
                  testdata.Rows.Add(6, "6", 2);
                  testdata.Rows.Add(7, "7", 3);
                  testdata.Rows.Add(8, "8", 3);
                  testdata.Rows.Add(9, "9", 7);
                  testdata.Rows.Add(10, "10", 7);
              
              }
  
          }
  
          [WebMethod]
          public static string DDLKeyAndValue(int ParentID) 
          {
              
              var result2 = from r in testdata.Select("ParentID=" + ParentID)
                            select new { Key = r["ID"], Value = r["Value"] };
  
             return JsonConvert.SerializeObject(result2);
          
          }

  Hope that helps, thanks.

  Best Regards!

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