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 question is related to
asp.net
drop-down-menu
Do your databinding and then add the following:
Dim liFirst As New ListItem("", "")
drpList.Items.Insert(0, liFirst)
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
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"
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
You can use AppendDataBoundItems=true
to easily add:
<asp:DropDownList ID="drpList" AppendDataBoundItems="true" runat="server">
<asp:ListItem Text="" Value="" />
</asp:DropDownList>
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();
}
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
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)
it looks like you are adding a blank item, and then databinding, which would empty the list; try inserting the blank item after databinding
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)
it looks like you are adding a blank item, and then databinding, which would empty the list; try inserting the blank item after databinding
it looks like you are adding a blank item, and then databinding, which would empty the list; try inserting the blank item after databinding
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
it looks like you are adding a blank item, and then databinding, which would empty the list; try inserting the blank item after databinding
Do your databinding and then add the following:
Dim liFirst As New ListItem("", "")
drpList.Items.Insert(0, liFirst)
simple
at last
ddlProducer.Items.Insert(0, "");
Do your databinding and then add the following:
Dim liFirst As New ListItem("", "")
drpList.Items.Insert(0, liFirst)
simple
at last
ddlProducer.Items.Insert(0, "");
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
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();
}
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"
Source: Stackoverflow.com