HtmlSelect populated dynamically, fails to return selected item

  • Thread starter Thread starter Stephen Miller
  • Start date Start date
S

Stephen Miller

When I dynamically populate a HtmlSelect combo box, the Value property
consistently fails to return the item selected, defaulting instead to
the first item in the list. For example:

Protected WithEvents Fruits As System.Web.UI.HtmlControls.HtmlSelect
Protected WithEvents Results As System.Web.UI.WebControls.Label
Protected WithEvents Button1 As System.Web.UI.WebControls.Button
…
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load

Dim values As ArrayList = New ArrayList()

values.Add("Apple")
values.Add("Lemon")
values.Add("Orange")
values.Add("Banana")

Fruits.DataSource = values
Fruits.DataBind()

End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
'Results.Text = Fruits.Items(Fruits.SelectedIndex).Text
Results.Text = Fruits.Value
End Sub


With the aspx:

<select id="Fruits" size="1" name="Fruits" runat="server"></select>
<asp:button id="Button1" runat="server" Text="Go"></asp:button>
<asp:label id="Results" runat="server">Results</asp:label>

Curiously, if I manually add the list items to the HtmlSelect control,
then the Value property correctly returns the selected menu item. For
example:

<select id="Fruits" size="1" name="Fruit2" runat="server">
<option selected>Apple</option>
<option>Lemon</option>
<option>Orange</option>
<option>Banana</option>
</select>

In both case, the resulting HTML is identical. Why does the DataBound
HtmlSelect fail to return the selected list item?

Thanks,

Stephen
 
Stephen Miller said:
When I dynamically populate a HtmlSelect combo box, the Value property
consistently fails to return the item selected, defaulting instead to
the first item in the list. For example:

Protected WithEvents Fruits As System.Web.UI.HtmlControls.HtmlSelect
Protected WithEvents Results As System.Web.UI.WebControls.Label
Protected WithEvents Button1 As System.Web.UI.WebControls.Button
.
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load

Dim values As ArrayList = New ArrayList()

values.Add("Apple")
values.Add("Lemon")
values.Add("Orange")
values.Add("Banana")

Fruits.DataSource = values
Fruits.DataBind()

End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles Button1.Click
'Results.Text = Fruits.Items(Fruits.SelectedIndex).Text
Results.Text = Fruits.Value
End Sub


With the aspx:

<select id="Fruits" size="1" name="Fruits" runat="server"></select>
<asp:button id="Button1" runat="server" Text="Go"></asp:button>
<asp:label id="Results" runat="server">Results</asp:label>

Curiously, if I manually add the list items to the HtmlSelect control,
then the Value property correctly returns the selected menu item. For
example:

<select id="Fruits" size="1" name="Fruit2" runat="server">
<option selected>Apple</option>
<option>Lemon</option>
<option>Orange</option>
<option>Banana</option>
</select>

In both case, the resulting HTML is identical. Why does the DataBound
HtmlSelect fail to return the selected list item?

Thanks,

Stephen
Click to expand...

Try to add the items dynamically in Page_Init instead of Page_Load.
The viewstate information (containing which item was selected) is added
before Page_Load, when your list is not yet filled.
 
Jos said:
Try to add the items dynamically in Page_Init instead of Page_Load.
The viewstate information (containing which item was selected) is added
before Page_Load, when your list is not yet filled.
Click to expand...

Jos,

That works, but is there a better way? I've got a lot of dependent
logic in the Page_Load method that I would rather not move or
replicate in Page_Init.

Interestingly, MSDN's sample code for HtmlSelect (see:
http://msdn.microsoft.com/library/d...n-us/cpgenref/html/cpconhtmlselectcontrol.asp)
shows DataBinding in Page_Load and an onClick event accessing the
control's Value method.

Stephen
 
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