DropDownList.SelectedIndexChanged w/ AutoPostBack = true; why doesn't it fire if the user selects the first item?

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
        MediaInfoDataEntryDataSet11.Clear()
        OleDbDataAdapter1.Fill(MediaInfoDataEntryDataSet11)

        If Not IsPostBack Then
            drpdSelectDate.DataBind()
        End If

        DataView1.RowFilter = "date = '" & drpdSelectDate.SelectedItem.Text & "'"
        Page.DataBind()

    End Sub

note: the DataView1 is based on the MediaInfoDataEntryDataSet1

Here is a simple example of the problem:

Create a webform with a textbox ('Textbox1') and a dropDownList('DropDownList1')

Then add the following code to the aspx.vb page

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Put user code to initialize the page here
        If Not IsPostBack Then
            DropDownList1.Items.Add("A")
            DropDownList1.Items.Add("B")
            DropDownList1.Items.Add("C")
            DropDownList1.AutoPostBack = True
        End If

    End Sub

    Private Sub DropDownList1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
        TextBox1.Text = DropDownList1.SelectedItem.Text
    End Sub


Now explain this:

When it first loads, "A" is showing in the listbox. If you select "A" it does nothing. If you select "B" it sets the textbox text to be "B." If you then select "B" nothing happens, but it works fine for the other items.

So I guess a better way of phrasing the question is this: is there a way to trigger the selectedIndexChanged when it selects anything?

Hi..
I guess it should work this way...
        If Not IsPostBack Then
            drpdSelectDate.DataBind()
            DataView1.RowFilter = "date = '" & drpdSelectDate.SelectedItem.Text & "'"
            Page.DataBind()
        End If


=Baan

I found a similar solution to my particular code that works, but its the general case that I want an answer for... see my previous post.

Thoughts on that?

True.

Thoughts on implementing a "onSelectAnything" event?

you know what.. actually there is no problem at all...
suppose, you select an item. then it will automatically show the data for it.. after that there is no point in selecting the same item agai. because you have already shown the data. it's still there...
So why do you want to select the same item again and trigger this event??

In my particular case it is the page.databind that is the culprit, since it is also then rebinding the DropDownList control i am using as my record selector. And since in that case the first item in the list doesn't trigger the selectedIndexChange event, so instead of using page.databind, i'm databinding all the controls individually.

Like so:

   'Put user code to initialize the page here
        MediaInfoDataEntryDataSet11.Clear()
        OleDbDataAdapter1.Fill(MediaInfoDataEntryDataSet11)

        If Not IsPostBack Then
            drpdSelectDate.DataBind()
        End If

        DataView1.RowFilter = "date = '" & drpdSelectDate.SelectedItem.Text & "'"

        tboxMediaInfoID.DataBind()
        tboxDate.DataBind()
        chkWma.DataBind()
        chkPdf.DataBind()
        tboxGuest.DataBind()
        tboxDescription.DataBind()
        tboxSource.DataBind()
        rbtnRTLSource.DataBind()

    End Sub

I used the solution in the following article to resolve the issue in my app.


http://authors.aspalliance.com/aldotnet/examples/adddefaultitemwithbind.aspx

It basicaly adds a new default item as the first item after doing the databind.

  'Put user code to initialize the page here
        MediaInfoDataEntryDataSet11.Clear()
        OleDbDataAdapter1.Fill(MediaInfoDataEntryDataSet11)

        If Not IsPostBack Then
            drpdSelectDate.DataBind()
           'Add an item as the first item to the drop Down list tellng the user to select a date
            drpdSelectDate.Items.Insert(0, "Select a Date")
            drpdSelectDate.SelectedIndex = 0


        End If

        DataView1.RowFilter = "date = '" & drpdSelectDate.SelectedItem.Text & "'"

        tboxMediaInfoID.DataBind()
        tboxDate.DataBind()
        chkWma.DataBind()
        chkPdf.DataBind()
        tboxGuest.DataBind()
        tboxDescription.DataBind()
        tboxSource.DataBind()
        rbtnRTLSource.DataBind()

    End Sub

How about just adding a blank record at the beginning?


'Your Prerender code

MyDropDownList.Items.AddAt(0, New ListItem( ))
MyDropDownList.SelectedIndex = 0