The first intem in a DropDownList is vanishing!

[mark4asp]

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:

<aspropDownList 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);
}

 

[Dunc]

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

 

[mark4asp]

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

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:

<aspropDownList 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?

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.