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The first intem in a DropDownList is vanishing!

P: n/a
The first intem in a DropDownList is vanishing!

My code to load a DropDownList is shown below. Yet when I load the
page after a postback there is no zeroth item present.

lstManager.Items.Clear();

lstManager.DataSource = _dsData.Tables["manager"].DefaultView;
lstManager.DataValueField = "ManagerID";
lstManager.DataTextField = "Name";
lstManager.DataBind();

lstManager.Items.Insert(0, new ListItem("none", "0"));
There's nothing special about the control definition:

<asp:DropDownList ID="lstManager" runat="server" Height="20px"
Width="250px" />

What's going on here?

This was the old code I replaced. Why does the old code (below) work
and why is my new code (above) broke?

lstManager.Items.Clear();

ListItem li = new ListItem("none","0");
lstManager.Items.Add(li);

foreach (DataRow drManager in _dsData.Tables["manager"].Rows)
{
ListItem liManager = new ListItem((string)drManager["Name"],
((int)drManager["ManagerID"]).ToString());
lstManager.Items.Add(liManager);
}

Jun 1 '07 #1
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2 Replies


P: n/a
I had this one a while back; turns out I was using simple properties
on a Master Page that required a DataBind() call to bind them. When
it was called, it was also rebinding the content page, which loses the
manually added items.

I recall this issue also happened with an ASCX file on the page, or if
you call a generic DataBind() any time after the addition of
ListItems, etc.

Dunc
http://www.fluidfoundation.com

On 1 Jun, 15:24, mark4asp <mark4...@gmail.comwrote:
The first intem in a DropDownList is vanishing!

My code to load a DropDownList is shown below. Yet when I load the
page after a postback there is no zeroth item present.

lstManager.Items.Clear();

lstManager.DataSource = _dsData.Tables["manager"].DefaultView;
lstManager.DataValueField = "ManagerID";
lstManager.DataTextField = "Name";
lstManager.DataBind();

lstManager.Items.Insert(0, new ListItem("none", "0"));

There's nothing special about the control definition:

<asp:DropDownList ID="lstManager" runat="server" Height="20px"
Width="250px" />

What's going on here?

This was the old code I replaced. Why does the old code (below) work
and why is my new code (above) broke?

lstManager.Items.Clear();

ListItem li = new ListItem("none","0");
lstManager.Items.Add(li);

foreach (DataRow drManager in _dsData.Tables["manager"].Rows)
{
ListItem liManager = new ListItem((string)drManager["Name"],
((int)drManager["ManagerID"]).ToString());
lstManager.Items.Add(liManager);
}

Jun 1 '07 #2

P: n/a
On 1 Jun, 16:30, Dunc <duncan.we...@gmail.comwrote:
I had this one a while back; turns out I was using simple properties
on a Master Page that required a DataBind() call to bind them. When
it was called, it was also rebinding the content page, which loses the
manually added items.

I recall this issue also happened with an ASCX file on the page, or if
you call a generic DataBind() any time after the addition of
ListItems, etc.

Dunchttp://www.fluidfoundation.com

On 1 Jun, 15:24, mark4asp <mark4...@gmail.comwrote:
The first intem in a DropDownList is vanishing!
My code to load a DropDownList is shown below. Yet when I load the
page after a postback there is no zeroth item present.
lstManager.Items.Clear();
lstManager.DataSource = _dsData.Tables["manager"].DefaultView;
lstManager.DataValueField = "ManagerID";
lstManager.DataTextField = "Name";
lstManager.DataBind();
lstManager.Items.Insert(0, new ListItem("none", "0"));
There's nothing special about the control definition:
<asp:DropDownList ID="lstManager" runat="server" Height="20px"
Width="250px" />
What's going on here?
This was the old code I replaced. Why does the old code (below) work
and why is my new code (above) broke?
lstManager.Items.Clear();
ListItem li = new ListItem("none","0");
lstManager.Items.Add(li);
foreach (DataRow drManager in _dsData.Tables["manager"].Rows)
{
ListItem liManager = new ListItem((string)drManager["Name"],
((int)drManager["ManagerID"]).ToString());
lstManager.Items.Add(liManager);
}- Hide quoted text -

- Show quoted text -
Thanks Dunc, for sharing that with me - that scenario you described
sounds very like mine.

Jun 1 '07 #3

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