CSharp - Use the var Keyword When Confused

Introduction

Sometime it may be a little unclear what data type you have.

You know it is an IEnumerable of some type T, but what is T?

You can assign the query results to a variable whose type is specified with the var keyword.

Then to get the type of the current value of that variable so you know what type T is.

Northwind db = new Northwind(@"Data Source=.\SQLEXPRESS;Initial Catalog=Northwind");  
  
var orders = db.Customers  
  .Where(c => c.Country == "USA" && c.Region == "WA")  
  .SelectMany(c => c.Orders);  
  
Console.WriteLine(orders.GetType());  

Related Topic

• Query Expressions
• Create Anonymous Types
• Collection Initialization on List
• Returning IEnumerable<T>, Yielding, and Deferred Queries
• Returning a List So the Query Is Executed Immediately and the Results Are Cached
• Using One of the Func Delegate Declarations
• Query with Intentional Exception Deferred Until Enumeration
• XML Query Using LINQ to XML
• Database Query Using LINQ to SQL
• Converting an Array of Strings to Integers and Sorting It
• Get SQL query via DataContext Log
• Create extension for string to convert string to double and bool
• LINQ to Objects Query
• Query Results Changing Between Enumerations

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