IDictionary and Connection.RetrieveStatistics .NET/C#

Question

I see code like the following in several books and examples online. The problem is they all feed in a single method into a dictionary object which requires two.

IDictionary statistics = connection.RetrieveStatistics();

Which returns the IDE error:

Error   1 Using the generic `type 'System.Collections.Generic.IDictionary<TKey,TValue>' requires '2' type arguments C:\Users\SGM7\Documents\ASPX 3_5 book code\Pro ASP.NET 3.5\Chapter07\Website\Tester.aspx.cs 22 9 C:\...\Website\`

So even though connection.RetrieveStatistics() returns pairs, how can I get IDictionary to accept connection.RetrieveStatistics()?

Here's the code block.

connection.Open();
connection.StatisticsEnabled = true;

IDictionary statistics = connection.RetrieveStatistics();

lblBytes.Text = "Received bytes: " + statistics["BytesReceived"].toString();
connection.Close();
lblBytes.Text += connection.State.ToString();

Answer 1

Right-click on RetrieveStatistics in your code block in VS and pick 'go to definition' to see how it is defined. My guess is it's a System.Collections.IDictionary, not a System.Collections.Generic.IDictionary<K,V>.

Or, if you're using .NET 3.5 or higher, use var:

var statistics = connection.RetrieveStatistics();

Answer 2

The compile error makes it looks like you're trying to use a generic dictionary instead of a non-generic Dictionary.

The return type of RetrieveStatistics() is IDictionary, not IDictionary<T,K>

Do you have a using declaration that's mapping IDictionary to something else? Have you tried using System.Collections.IDictionary explicitly?

For example:

System.Collections.IDictionary statistics = connection.RetrieveStatistics();

As Jonathan says, var will also work, because the compiler will just figure out what the type should be.