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LinqDataSource - Can you limit the amount of records returned?

I'd like to use a LinqDataSource control on a page and limit the amount of records returned. I know if I use code behind I could do something like this:

IEnumerable<int> values = Enumerable.Range(0, 10);
IEnumerable<int> take3 = values.Take(3);

Does anyone know if something like this is possible with a LinqDataSource control?

[Update]

I'm going to use the LinqDataSource with the ListView control, not a GridView or Repeater. The LinqDataSource wizard does not provide the ability to limit the number of records return. The Advanced options only allow you to enabled deletes, inserts, and updates.

like image 690
Otto Avatar asked Aug 07 '08 00:08

Otto


2 Answers

I had this same issue. The way I got round this was to use the Selecting event on the LinqDataSource and return the result manually.

e.g.

protected void lnqRecentOrder_Selecting(object sender, LinqDataSourceSelectEventArgs e)
{
    DataClassesDataContext dx = new DataClassesDataContext();
    e.Result = (from o in dx.Orders
                where o.CustomerID == Int32.Parse(Request.QueryString["CustomerID"])
                select o).Take(5);
}
like image 159
Ollie Avatar answered Nov 11 '22 15:11

Ollie


Yes and No.

No, you cannot limit the results within the LinqDataSource control. Because Linq uses deferred execution, the expectation is that the presentation control will do the recordset limits.

Yes, you can do this with a ListView control. The trick is to use the DataPager control within the LayoutTemplate, like so:

<LayoutTemplate>
  <div id="itemPlaceholder" runat="server" />
  <asp:DataPager ID="DataPager1" runat="server" PageSize="3">
  </asp:DataPager>            
</LayoutTemplate>

Normally, you would include controls inside the DataPager like first, last, next, and previous. But if you just make it empty, then you will only see the three results that you desire.

Hope this helps.

like image 13
Portman Avatar answered Nov 11 '22 16:11

Portman