Populating a Dropdown List on Page Load

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Populating a Dropdown List on Page Load

Last post 09-27-2006 6:06 PM by PeterBrunone. 7 replies.

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Populating a Dropdown List on Page Load

09-27-2006, 12:05 AM

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roseability
Joined on 07-20-2006, 2:23 AM
Posts 18

I'd like to populate a dropdown list on page load, on a web form.

Like this:

<%
Dim thisYear
Dim nextYear
Date.Today.Year.ToString(thisYear)
nextYear = thisYear + 1
%>

<asp:DropDownList ID="DateYear" runat="server">
<asp:ListItem><% response.write(thisYear) %></asp:ListItem>
<asp:ListItem><% response.write(nextYear) %></asp:ListItem>
</asp:DropDownList>

Obviously, that code does not work. I'd also like to use the code-behind way of doing things. I had a crack at using the Page_Init method, but didn't seem to be able to get anything happening.

Any help much appreciated =).

Filed under: form, DropDownList, ASP.NET 2.0

Re: Populating a Dropdown List on Page Load

09-27-2006, 1:20 AM

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mokeefe
Joined on 08-20-2006, 5:15 AM
Canberra Australia
Posts 2,096

Try this for an example

<%@ Page Language="VB" AutoEventWireup="false" CodeFile="DropDownDate.aspx.vb" Inherits="DropDownDate" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<title>Untitled Page</title>

</head>

<body>

<div>

<asp:DropDownList ID="DropDownList1" runat="server" Width="272px">

</asp:DropDownList></div>

</form>

</body>

</html>

Code Behind

Partial Class DropDownDate

Inherits System.Web.UI.Page

Protected Sub Page_PreInit(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.PreInit

If Not Me.IsPostBack Then

Dim Dates As New Collections.Generic.List(Of System.DateTime)

' Add next 5 years

For i As Integer = 1 To 5

Dates.Add(System.DateTime.Now.AddYears(i))

Me.DropDownList1.DataSource = Dates

Me.DropDownList1.DataTextField = "Year"

Me.DropDownList1.DataBind()

End If

End Sub

End Class

Regards,

Martin.

Rgds,
Martin.

For the benefit of all users please mark any post answers as appropriate.

Re: Populating a Dropdown List on Page Load

09-27-2006, 1:58 AM

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roseability
Joined on 07-20-2006, 2:23 AM
Posts 18

Thanks Martin, that worked out of the box =). I changed- 'Add next 5 years For i As Integer = 1 To 5 Dates.Add(System.DateTime.Now.AddYears(i)) Next -to- Dates.Add(System.DateTime.Now) 'Add next 5 years For i As Integer = 1 To 5 Dates.Add(System.DateTime.Now.AddYears(i)) Next - so that I got the current year as well. Cheers!

Re: Populating a Dropdown List on Page Load

09-27-2006, 2:00 AM

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roseability
Joined on 07-20-2006, 2:23 AM
Posts 18

'Scuse formatting! That was-

'Add next 5 years
For i As Integer = 1 To 5
Dates.Add(System.DateTime.Now.AddYears(i))
Next

-to-

Dates.Add(System.DateTime.Now)
'Add next 5 years
For i As Integer = 1 To 5
Dates.Add(System.DateTime.Now.AddYears(i))
Next

- so that I got the current year as well.

Re: Populating a Dropdown List on Page Load

09-27-2006, 2:43 AM

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mokeefe
Joined on 08-20-2006, 5:15 AM
Canberra Australia
Posts 2,096

I actually dropped some other code that I had added that was superfluos to your question. I decided it was better to keep it to the point and I also dropped a similar line from the code regarding current year; expected you to do -

' Add this year and next 5 years

For i As Integer = 0 To 5

Very glad to be of help.

Martin.

Rgds,
Martin.

For the benefit of all users please mark any post answers as appropriate.

Re: Populating a Dropdown List on Page Load

09-27-2006, 12:16 PM

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PeterBrunone
Joined on 06-19-2002, 9:15 AM
I'm standing behind you.
Posts 3,663

This is just a nitpick really, but if you're going to create the data in a loop, you don't need a separate List object to hold the items. Just put them into the list as you generate them, e.g.

Partial Class DropDownDate

Inherits System.Web.UI.Page

Protected Sub Page_PreInit(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.PreInit

If Not Me.IsPostBack Then

' Add next 5 years

For i As Integer = 1 To 5

Me.DropDownList1.Items.Add(System.DateTime.Now.AddYears(i))

End If

End Sub

End Class

(minus the change you made later in the thread)

Cheers,

Peter Brunone
MS MVP, ASP.NET
Founder, EasyListBox.com
Do the impossible, and go home early.

Re: Populating a Dropdown List on Page Load

09-27-2006, 5:48 PM

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mokeefe
Joined on 08-20-2006, 5:15 AM
Canberra Australia
Posts 2,096

Hi Peter,

Just another two bits worth.

I did consider the simpler approach, but felt it appropriate to provide a fuller example where the user could get a selected date as a DateTime object for later use.

Martin.

Rgds,
Martin.

For the benefit of all users please mark any post answers as appropriate.