Custom DropDownList - Can't get SelectedValue

Question

User-1235926091 posted

I am trying to build a simple Custom DDL and am having a problem coming up with the Selected Value.

My CC looks like this

 

Imports System
Imports System.Web.UI
Imports System.Web.UI.WebControls

Namespace MyCC

    Public Class MyCC

        Inherits DropDownList
        Private ddl1 As New DropDownList()

        Protected Overloads Overrides Sub Render(ByVal writer As HtmlTextWriter)

            ddl1.Items.Add(New ListItem("Item 1", "Value 1"))
            ddl1.Items.Add(New ListItem("Item 2", "Value 2"))
            ddl1.Items.Add(New ListItem("Item 3", "Value 3"))
            ddl1.Items.Add(New ListItem("Item 4", "Value 4"))

            ddl1.RenderControl(writer)
        End Sub

    End Class

End Namespace

 Then in the site

ASPX

 
        <cc1:MyCC ID="MyCC1" runat="server" /><br />
        <asp:Button ID="Button1" runat="server" Text="Button" /><br />
        <asp:Label ID="Label1" runat="server" />
   

ASPX.VB

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click

        Label1.Text = MyCC1.SelectedValue
    End Sub

 

Answer 1

User1906575742 posted

Try this

MyCC1.SelectedItem.Value

Or

MyCC1.SelectedItem.Text

Answer 2

User-1235926091 posted

No Dice, but I have found the answer... looks like I was rendering my control wrong

Imports System
Imports System.Web.UI
Imports System.Web.UI.WebControls


Namespace MyCC
    <ToolboxData("<{0}:MyCC ID=""MyCC1"" runat=""server""></{0}:MyCC>")> _
    Public Class MyCC

        Inherits DropDownList


        Protected Overloads Overrides Sub CreateChildControls()
            If Not Page.IsPostBack Then
                Items.Add(New ListItem("Item 1", "Value 1"))
                Items.Add(New ListItem("Item 2", "Value 2"))
                Items.Add(New ListItem("Item 3", "Value 3"))
                MyBase.CreateChildControls()
            End If
        End Sub

    End Class

End Namespace

 

Answer 3

User-16411453 posted

 This is for a couple of your post I saw.  Mark ddl1 public in declarations to access it from the outside

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Text
Imports System.Web
Imports System.Web.UI
Imports System.Web.UI.WebControls


<DefaultProperty("Text"), ToolboxData("<{0}:WebCustomControl1 runat=server></{0}:WebCustomControl1>")> _
Public Class WebCustomControl1
	Inherits WebControl

	Private ddl1 As DropDownList
	Protected Overrides Sub Render(ByVal writer As HtmlTextWriter)

		If Not Me.Context Is Nothing Then
			RenderContents(writer)
		Else
			RenderDesignMode(writer)
		End If

	End Sub
	Protected Overrides Sub OnInit(ByVal e As System.EventArgs)
		MyBase.OnInit(e)

		Controls.Clear()

		ddl1 = New DropDownList
		With ddl1
			.ID = [ID] & "_ddl1"
			.Width = 80%
			.Style.Add(HtmlTextWriterStyle.Width, "80%")
			.AutoPostBack = True
			AddHandler .SelectedIndexChanged, AddressOf ddl1_SelectedIndexChanged

		End With
		Controls.Add(ddl1)

	End Sub
	Private Sub RenderDesignMode(ByVal writer As HtmlTextWriter)

		Controls.Clear()

		ddl1 = New DropDownList
		With ddl1
			.ID = [ID] & "_ddl1"
			.Width = 80%
			.Style.Add(HtmlTextWriterStyle.Width, "80%")
			.AutoPostBack = True
			AddHandler .SelectedIndexChanged, AddressOf ddl1_SelectedIndexChanged

		End With
		Controls.Add(ddl1)

		RenderControl(writer)

	End Sub
	Protected Overrides Sub OnLoad(ByVal e As System.EventArgs)
		MyBase.OnLoad(e)

		If Not Page.IsPostBack Then
			Load_ddl1()
		End If

	End Sub
	Private Sub Load_ddl1()

		ddl1.Items.Clear()
		ddl1.Items.Add(New ListItem("Item 1", "Value 1"))
		ddl1.Items.Add(New ListItem("Item 2", "Value 2"))
		ddl1.Items.Add(New ListItem("Item 3", "Value 3"))
		ddl1.Items.Add(New ListItem("Item 4", "Value 4"))

	End Sub
	Protected Sub ddl1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs)

		myValue = ddl1.SelectedValue

	End Sub

End Class