public void CompareDeclarationExpressions()
{
var products = new[]
{
new { Id = 1, Name = "Bike", PriceAsString = "1000" },
new { Id = 2, Name = "Car", PriceAsString = "20000" },
new { Id = 3, Name = "Plane", PriceAsString = "A lot of money!" }
};
// Our goal: Calculate total price and ignore prices that
// contain invalid characters.
// Calculate total price (old style)
var totalPrice = products
.Sum(p =>
{
int price;
if (Int32.TryParse(p.PriceAsString, out price))
{
return price;
}
return 0;
});
Assert.AreEqual(21000, totalPrice);
// Calculate total price (new style)
totalPrice = products
.Sum(p => Int32.TryParse(p.PriceAsString, out var price) ? price : 0);
Assert.AreEqual(21000, totalPrice);
// Declare variable in expression.
int x = 1;
int y = 1;
if (var areEqual = x != y)
{
Assert.Fail();
}
}