Listbox SelectedIndex set to -1

[Greg Larsen]

I populate an unbound ListBox on a WebForm with the following C# code.

SqlDataReader oDr = sqlCommandGetTableList.ExecuteReader();
ListBoxTableName.DataSource = oDr;
ListBoxTableName.DataValueField = "TABLE_NAME";
ListBoxTableName.DataBind();

But when the WebForm is displayed and I highlight a TABLE_NAME in the
listbox the ListBoxTableName_SelectedIndexChanged method fires, but the
SelectedIndex value is -1. What am I doing wrong?

[Peter Bromberg [C# MVP]]

Are you closing your SqlDataReader and / or the underlying SqlConnection?
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Greg Larsen" wrote:

I populate an unbound ListBox on a WebForm with the following C# code.

SqlDataReader oDr = sqlCommandGetTableList.ExecuteReader();
ListBoxTableName.DataSource = oDr;
ListBoxTableName.DataValueField = "TABLE_NAME";
ListBoxTableName.DataBind();

But when the WebForm is displayed and I highlight a TABLE_NAME in the
listbox the ListBoxTableName_SelectedIndexChanged method fires, but the
SelectedIndex value is -1. What am I doing wrong?

[Greg Larsen]

No.

I fixed the problem by changing my code to read like this:

sqlConnectionTableList.Open();
SqlDataReader oDr = sqlCommandGetTableList.ExecuteReader();
ListBoxTableName.DataSource = oDr;
ListBoxTableName.DataValueField = "TABLE_NAME";
if (!IsPostBack)
{
ListBoxTableName.DataBind();
}


"Peter Bromberg [C# MVP]" wrote:

Are you closing your SqlDataReader and / or the underlying SqlConnection?
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Greg Larsen" wrote:

I populate an unbound ListBox on a WebForm with the following C# code.

SqlDataReader oDr = sqlCommandGetTableList.ExecuteReader();
ListBoxTableName.DataSource = oDr;
ListBoxTableName.DataValueField = "TABLE_NAME";
ListBoxTableName.DataBind();

But when the WebForm is displayed and I highlight a TABLE_NAME in the
listbox the ListBoxTableName_SelectedIndexChanged method fires, but the
SelectedIndex value is -1. What am I doing wrong?

[Peter Bromberg [C# MVP]]

good, but you still need to CLOSE your DataReader when you are done, because
it holds the connection open. You can use CommandBehavior.CloseConnection
overload, and the closing of the reader will also close the connection.
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Greg Larsen" wrote:

No.

I fixed the problem by changing my code to read like this:

sqlConnectionTableList.Open();
SqlDataReader oDr = sqlCommandGetTableList.ExecuteReader();
ListBoxTableName.DataSource = oDr;
ListBoxTableName.DataValueField = "TABLE_NAME";
if (!IsPostBack)
{
ListBoxTableName.DataBind();
}


"Peter Bromberg [C# MVP]" wrote:

Are you closing your SqlDataReader and / or the underlying SqlConnection?
Peter

--
Co-founder, Eggheadcafe.com developer portal:
http://www.eggheadcafe.com
UnBlog:
http://petesbloggerama.blogspot.com


"Greg Larsen" wrote:

I populate an unbound ListBox on a WebForm with the following C# code.
>
SqlDataReader oDr = sqlCommandGetTableList.ExecuteReader();
ListBoxTableName.DataSource = oDr;
ListBoxTableName.DataValueField = "TABLE_NAME";
ListBoxTableName.DataBind();
>
But when the WebForm is displayed and I highlight a TABLE_NAME in the
listbox the ListBoxTableName_SelectedIndexChanged method fires, but the
SelectedIndex value is -1. What am I doing wrong?
>