How to check if LinqDataSource is empty after selecting?

Question

I have an asp.NET application where I use a LinqDataSource control to fill a ListView control. Here's the code for my LinqDataSource control's OnSelecting command:

protected void lds_Selecting(object sender, LinqDataSourceSelectEvenArgs e)
{
    var db = new Models.EF.Entities();
    e.Result = from x in db.Sliders
                where x.IsPublic == true
                select x;
}

This works great but now I want to run an if statement in the case that the result is empty. How can I see if the result is empty?

Gilad Green · Accepted Answer · 2016-08-15T14:10:15.303

1

Use the Any method. Plus, LinqDataSourceSelectEvenArgs stores the data as an object so cast so use the as to get the IEnumerable<T> on which you can run the Any:

e.Result = (from x in db.Sliders
            where x.IsPublic == true
            select x);

var collection = e.Result as IEnumerable<Slider>;
if(collection != null && !collection.Any()) 
{ 
    /*your code*/
}

edited Aug 15 '16 at 14:10

answered Aug 15 '16 at 13:54

Gilad Green

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'object' does not contain a definition for 'Any' and no extension method 'Any' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?) – Barry Michael Doyle Aug 15 '16 at 13:57
Ok, but I actually asked for it to run only if the result IS empty, so if(!collection.Any()) {} works, thanks for leading me to a solution. – Barry Michael Doyle Aug 15 '16 at 14:09
Happy it helped :) – Gilad Green Aug 15 '16 at 14:10

How to check if LinqDataSource is empty after selecting?

1 Answers1