Why doesn't this LINQ Query Work?

Question

I was attempting to help someone else out and wrote this query:

var foundTab = (from tab in tabControl1.TabPages
                where tab.Name == "tabName"
                select tab).First();

And they reported that they received this error:

Could not find an implementation of the query pattern for source type System.Windows.Forms.TabControl.TabPageCollection'. 'Where' not found. Consider explicitly specifying the type of the range variable 'tab'.

I checked MSDN and TabPageCollection implements IList, ICollection, IEnumerable. So, what's going on here? What does that error mean and is there another way to query the Tab Control's TabPages property?

Answer 1

Try this:

var tab = (from System.Windows.Forms.TabPage tab in tabControl1.TabPages
           where tab.Name == "tabName"
           select tab).First();

This code specifies the type of the range variable.

Answer 2

Try this:

var tab = tabControl1.TabPages.FirstOrDefault(t => t.Name == "tabName");

Also, make sure you have

using System.Linq;

at the top of your file.

Dylan

Answer 3

TabPageCollection implements IEnumerable but not IEnumerable<T> which is what LINQ uses. To fix, use the cast method like so:

var foundTab = (from tab in tabControl1.TabPages.Cast<TabPage>()
            where tab.Name == "tabName"
            select tab).First();