Asp.net - Add blank item at top of dropdownlist

Question

Why is the dropdown not showing my blank item first? Here is what I have

drpList.Items.Add(New ListItem("", ""))

With drpList
    .DataSource = myController.GetList(userid)
    .DataTextField = "Name"
    .DataValueField = "ID"
    .DataBind()
End With

Edit ~ I am binding to a Generig List, could this be the culprit?

This relates to: http://stackoverflow.com/questions/983716/asp-net-dropdownlist-add-blank-line-before-db-values — mcfea, Apr 16 '14 at 23:19

score 284 · Accepted Answer · edited Oct 07 '11 at 22:58

284

After your databind:

drpList.Items.Insert(0, new ListItem(String.Empty, String.Empty));
drpList.SelectedIndex = 0;

edited Oct 07 '11 at 22:58

Bob Kaufman

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answered Nov 05 '08 at 23:05

JasonS

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Alternately, you can instantiate a ListItem, set its Selected property to true, and then insert it into drpList as above. – nikodaemus Jun 15 '15 at 16:22
3

*This may help those looking for an answer to work with sqlDataSource data* In my case, I also had to add drpList.AppendDataBoundItems = true; to bind it to the current data in the Page_Load method – sabastienfyrre Sep 14 '15 at 14:47

score 34 · Answer 2 · edited Feb 09 '21 at 08:08

34

You can use AppendDataBoundItems=true to easily add:

<asp:DropDownList ID="drpList" AppendDataBoundItems="true" runat="server">
    <asp:ListItem Text="" Value="" />
</asp:DropDownList>

edited Feb 09 '21 at 08:08

Matthew Lock

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answered Nov 28 '12 at 02:57

ayhtut

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VS doesn't like the
tag and it works for me without it. This is such a clean option, I don't know why it doesn't have more votes. – Tony L. May 21 '15 at 14:29
Worked like a charm. Thanks for the design time solution. – DataCat Robin Aug 27 '15 at 14:26
3

Don't forget to set Selected="true" – Fandango68 Feb 24 '16 at 23:35

score 25 · Answer 3 · answered Nov 05 '08 at 23:02

25

The databinding takes place after you've added your blank list item, and it replaces what's there already, you need to add the blank item to the beginning of the List from your controller, or add it after databinding.

EDIT:

After googling this quickly as of ASP.Net 2.0 there's an "AppendDataBoundItems" true property that you can set to...append the databound items.

for details see

http://imar.spaanjaars.com/QuickDocId.aspx?quickdoc=281 or

http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.listcontrol.appenddatabounditems.aspx

answered Nov 05 '08 at 23:02

Whisk

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One think you need to watch out for is having your dropdown list grow after each postback by appending the same data over and over. – Keith Sirmons Nov 05 '08 at 23:07
Is the blank item not there, or there but just not selected? – Whisk Nov 05 '08 at 23:07
This would work if you had the blank one in your .aspx markup, then bound in code behind. – John Sheehan Nov 05 '08 at 23:38

score 13 · Answer 4 · answered Mar 18 '09 at 17:36

I think a better way is to insert the blank item first, then bind the data just as you have been doing. However you need to set the AppendDataBoundItems property of the list control.

We use the following method to bind any data source to any list control...

public static void BindList(ListControl list, IEnumerable datasource, string valueName, string textName)
{
    list.Items.Clear();
    list.Items.Add("", "");
    list.AppendDataBoundItems = true;
    list.DataValueField = valueName;
    list.DataTextField = textName;
    list.DataSource = datasource;
    list.DataBind();
}

score 9 · Answer 5 · answered Oct 30 '10 at 20:14

Like "Whisk" Said, the trick is in "AppendDataBoundItems" property

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        DropDownList1.AppendDataBoundItems = true;
        DropDownList1.Items.Insert(0, new ListItem(String.Empty, String.Empty));
        DropDownList1.SelectedIndex = 0;
    }
}

Thanks "Whisk"

score 5 · Answer 6 · answered Nov 05 '08 at 23:04

5

Do your databinding and then add the following:

Dim liFirst As New ListItem("", "")
drpList.Items.Insert(0, liFirst)

answered Nov 05 '08 at 23:04

Dillie-O

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score 3 · Answer 7 · edited May 08 '12 at 18:27

3

simple

at last

ddlProducer.Items.Insert(0, "");

edited May 08 '12 at 18:27

arrowd

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answered May 08 '12 at 12:50

Umesh

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Steven A. Lowe · Answer 8 · 2008-11-05T23:06:50.813

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it looks like you are adding a blank item, and then databinding, which would empty the list; try inserting the blank item after databinding

edited Nov 05 '08 at 23:06

answered Nov 05 '08 at 23:01

Steven A. Lowe

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when I do that, the blank row appears at the bottom. – Saif Khan Nov 05 '08 at 23:04
You can specify the index to insert into. Look at JasonS' solution. – AndyG Nov 05 '08 at 23:06
@[Saif Khan]: and if that doesn't work, insert the blank row into your datasource, then databind – Steven A. Lowe Nov 05 '08 at 23:08

Chưa biết · Answer 9 · 2014-05-18T12:22:45.117

1

ddlCategory.DataSource = ds;
ddlCategory.DataTextField = "CatName";
ddlCategory.DataValueField = "CatID";

Cách 1:

ddlCategory.Items.Add(new ListItem("--please select--", "-1"));
ddlCategory.AppendDataBoundItems = true;
ddlCategory.SelectedIndex = -1;

ddlCategory.DataBind();

Cách 2:

ddlCategory.Items.Insert(0, new ListItem("-- please select --", "0"));

(Tested OK)

edited May 18 '14 at 12:22

answered Apr 24 '13 at 08:10

Chưa biết

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score 0 · Answer 10 · edited Mar 02 '15 at 21:58

0

You could also have a union of the blank select with the select that has content:

select '' value, '' name
union
select value, name from mytable

edited Mar 02 '15 at 21:58

Undo

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answered Mar 02 '15 at 21:53

BitsAndBytes

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Looking back, I wouldn't recommend this method except only as an alternative. I like the event for flexibility sake (OnDataBound="mydropdown_DataBound"), but in my current case, I'm adopting the (AppendDataBoundItems="true") for simplicity sake. – BitsAndBytes Mar 03 '15 at 14:55

Asp.net - Add blank item at top of dropdownlist

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