Question

I recently was assigned to update an old project who use the asp:listbox control (which I’m not very good at handling).

The set up is that the ListBox is placed on a aspx.page and fills itself with data through the DataSource attribute.
The columns database table populating the ListBox is activity_points (datatype float) and activity_title (datatype string / varchar).
The ListBox gets filled out and everything looks fine until i check whats in the value of the list items.

The ListBox looks as follows

<asp:ListBox runat="server" DataSource="<%# GetActivitys(1) %>" DataTextField="activity_title"
DataValueField="activity_points" EnableViewState="true" onchange="DataChanged();SumUpRow(this,true);"
Width="200" CssClass="ddl-activity1" ID="activities_1_1" Rows="1" />

The default method (which I inherited) looks like this

public SqlDataReader GetActivitys(int type)
{
    SqlConnection conn = new SqlConnection(umbraco.GlobalSettings.DbDSN);
    SqlCommand cmd = new SqlCommand("SELECT * FROM " + DATABASE_TABLE_ACTIVITIES + " WHERE activity_type=" + type.ToString() + " ORDER BY activity_type, activity_sortorder, activity_title", conn);
    cmd.Connection.Open();
    return cmd.ExecuteReader(CommandBehavior.CloseConnection);
}

The generated list items look like this

<option value="6">testing</option>
<option value="9">testing</option>
<option value="6,5">testing</option>
<option value="5">testing</option>
<option value="7">testing</option>
<option value="4,5">testing</option>
<option value="6.0">testing</option>
<option value="4">testing</option>
<option value="3.0">testing</option>
<option value="6.00">testing</option>
<option value="3,5">testing</option>
<option value="6.000">testing</option>

As clearly seen it mixes points and commas, and it adds a zero after each occurrence if the same value is repeated. If I render the same result set to a GridView everything looks fine!

Just to ensure that the data returned from the database is correct I’ve created a new method that converts the activity_points column

public DataTable GetActivitys(int type)
{
    string query = "SELECT activity_points, activity_title, activity_id FROM " + DATABASE_TABLE_ACTIVITIES + " WHERE activity_type=" + type.ToString() + " ORDER BY activity_type, activity_sortorder, activity_title";
    SqlConnection conn = new SqlConnection(umbraco.GlobalSettings.DbDSN);
    SqlDataAdapter da = new SqlDataAdapter(query, conn);
    DataTable dt = new DataTable();
    da.Fill(dt);

    /**/

    DataTable dtActivity = new DataTable();
    DataColumn ActivityCol;

    ActivityCol = new DataColumn();
    ActivityCol.DataType = Type.GetType("System.String");
    ActivityCol.ColumnName = "activity_points";
    dtActivity.Columns.Add(ActivityCol);

    ActivityCol = new DataColumn();
    ActivityCol.DataType = Type.GetType("System.String");
    ActivityCol.ColumnName = "activity_title";
    dtActivity.Columns.Add(ActivityCol);

    ActivityCol = new DataColumn();
    ActivityCol.DataType = Type.GetType("System.Int32");
    ActivityCol.ColumnName = "activity_id";
    ActivityCol.Unique = true;
    dtActivity.Columns.Add(ActivityCol);


    foreach (DataRow item in dt.Rows)
    {
        DataRow activityRow = dtActivity.NewRow();
        activityRow["activity_points"] = Convert.ToDouble(item["activity_points"]);
        activityRow["activity_title"] = item["activity_title"];
        activityRow["activity_id"] = item["activity_id"];

        dtActivity.Rows.Add(activityRow);
    }

    return dtActivity;
}

Im running out of options, is there something magic about ListBoxes that I missed?

Any advice is highly appreciated!

Thanks

Answer 1

Appears as if the listbox values always gets an incremental value of an integer