In this community post, canalso describes an issue with removing a Panel from a Placeholder within an ASP.NET ListView using C#, seeking advice on how to perform this task based on a row condition.

Issue Overview

The author describes a scenario in an ASP.NET WebForms application using C# where they want to conditionally remove a Panel (named panel01) from a Placeholder inside each row of a ListView. The condition is based on a database field: if BidEndWithError (from the data row) equals 'no', then panel01 should be removed for that row.

However, the author is facing a problem where all instances of panel01 are being removed from all rows, not simply the ones that match the condition in the DataTable.

Sample Code (Simplified)

protected void lv01_ItemDataBound(object sender, ListViewItemEventArgs e)
{
    if (e.Item.ItemType == ListViewItemType.DataItem)
    {
        string constr = ConfigurationManager.ConnectionStrings["bidsystemdb"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            DataTable dt = new DataTable();
            string strSQL = "Select * from BidTable2";
            SqlDataAdapter adpt = new SqlDataAdapter(strSQL, con);
            adpt.Fill(dt);
            
            for (int ij = 0; ij < e.Item.Controls.Count; ij++)
            {
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    if (dt.Rows[i]["BidEndWithError"].ToString() == "no")
                    {
                        PlaceHolder _phLabel = e.Item.Controls[ij].FindControl("phLabel") as PlaceHolder;
                        Panel _pnlLabel = e.Item.Controls[ij].FindControl("panel01") as Panel;
                        _phLabel.Controls.Remove(_pnlLabel);
                        // ... other update code
                    }
                }
            }
        }
    }
}

Analysis

  • The code loops through all controls (ij) for each item (row) in the ListView.
  • Then, for each database row (i), it checks if BidEndWithError is 'no' and tries to remove panel01 from phLabel.
  • This double loop causes the removal logic to run multiple times, resulting in all panels being removed, not just those matching the specific data item.

Correct Approach

  • In the ItemDataBound event, you generally work with one row/item at a time. You do not need to fetch all rows from the database again or loop.
  • The ListView’s DataItem property contains the data for that one row. Use this to determine whether to remove the panel.

Suggested Solution:

protected void lv01_ItemDataBound(object sender, ListViewItemEventArgs e)
{
    if (e.Item.ItemType == ListViewItemType.DataItem)
    {
        DataRowView rowView = e.Item.DataItem as DataRowView;
        if (rowView != null && rowView["BidEndWithError"].ToString() == "no")
        {
            PlaceHolder phLabel = e.Item.FindControl("phLabel") as PlaceHolder;
            Panel pnlLabel = e.Item.FindControl("panel01") as Panel;
            if (phLabel != null && pnlLabel != null)
            {
                phLabel.Controls.Remove(pnlLabel);
            }
        }
    }
}

Key Points:

  • Use e.Item.DataItem to get the data for the current row.
  • No need to query the database or iterate over rows inside ItemDataBound.
  • Only remove the panel if the current data item meets the condition.

Conclusion

By adjusting your code to operate on the current DataItem during binding, you can correctly target the panel in the relevant row rather than applying the logic to all rows. This results in only the intended panel being removed when the condition is met.

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