ASP.NET数据源参数问题

Question

I have a GridView and I want to add some more parameters to the DataSource. One of the parameters is called symbols and is a DataTable , and I'm not sure how to add it. Here's my GridView :

<asp:GridView  
    ID="grdTrades" 
    runat="server" 
    DataKeyNames="tradeId"
    DataSource="srcTrades"
    EnablePersistedSelection="true"            
    AllowPaging="true" 
    AllowSorting="true"
    PageSize = "10" 
    AutoGenerateColumns="false"         
    >
    <Columns>
        <asp:BoundField DataField="tradeId" HeaderText="TradeId"  SortExpression="tradeId" />
        ... some more columns ...
    </Columns>
</asp:GridView>

Here's my current data source.

<asp:ObjectDataSource
    id="srcTrades" 
    TypeName="DatabaseComponent.DBUtil" 
    SelectMethod="GetTrades" 
    DeleteMethod="DeleteTrade"             
    runat="server">
    <SelectParameters>
        <asp:ControlParameter Name="tradeTypeId" ControlID="ddlTradeTypes" PropertyName="SelectedValue" />
        <asp:ControlParameter Name="dateFrom" ControlID="txtDateFrom" PropertyName="Text" />
        <asp:ControlParameter Name="dateTo" ControlID="txtDateTo" PropertyName="Text" />            
    </SelectParameters>
    <DeleteParameters>
        <asp:ControlParameter Name="tradeId" ControlId="grdTrades" PropertyName="SelectedValue"  />
    </DeleteParameters> 
</asp:ObjectDataSource>

I want to pass an extra parameter called symbols which is a DataTable . I populate the DataTable with this code:

DataTable symbols = GetSelectedItems("symbol", listSymbols);

GetSelectedItems looks like this:

private DataTable GetSelectedItems(string column, ListBox _listbox)
{
    DataTable items = new DataTable();
    items.Columns.Add(column, System.Type.GetType("System.String"));

    foreach (ListItem item in _listbox.Items)
    {
        if (item.Selected)
        {
            DataRow dr = items.NewRow();
            dr[column] = item.Value;
            items.Rows.Add(dr);
        }
    }
    return items;
} 

I did try and bind the data myself and removing the ObjectDataSource entirely but then the sorting and paging events weren't handled. How would you solve this little issue?

Thanks!

Answer 1

You can use xml type (and a simple string SelectParameter) instead of DataTable:

1. Page_Load: Serialize selected items of listbox into xml
   and assign his text into the SelectParameter
2. GetTrades: Deserialize xml from the SelectParameter into a List<> local variable

Answer 2

    XElement x = new XElement("root",
        from i in _listbox.Items.OfType<ListItem>()
        where i.Selected
        select new XElement("row", i.Value));
    string s = x.ToString();