Why empty assignment compiled with no errors

Question

Here is my snippet:

var country = BLLocations.Instance.GetCountries();
ddlCountry.DataSource = 
ddlCountry.DataTextField = "Country";
ddlCountry.DataValueField = "CountryCode";
ddlCountry.DataBind();

See the second line:

ddlCountry.DataSource = 

And it compiled successfully and published to cloud also. Strange!

Answer 1

It's simply this:

ddlCountry.DataSource =  ddlCountry.DataTextField = "Country";

The line break doesn't effect, Which is a valid code.

Just like:

var x = 2;
var y = 3;
x = y = 1000;

(Note this is really not good practice at all! it's confusing and hard to disgust)

Every code in C# returns a value(though the value can be void) which lets you do this lazy loading:

return x ?? x = new ExpensiveObject();//

What it does:

1. If x is not null returns x.
2. If x is null assigns x new ExpensiveObject() an returns the assignment value - x.

Helpful feature but be careful with it.