如何将此SQL语句转换为Linq-to-SQL方法？

Question

For example, imagine that I want to see if a user exists in my database:

Select * from Users where inputID = Users.ID

Then if that result brought > 0 items, then the user exists, correct?

How can I do something like this using a pure Linq-to-SQL class?

Answer 1

dbContext.Users.Any(x => x.ID == inputID)

Answer 2

var user = dbContext.GetTable<User>().SingleOrDefault(u => u.ID == inputID);
bool userExists = user != null;

That will fetch the matching user from the database, if you just want to check for existance you can do this:

int matchingUsers = dbContext.GetTable<User>().Count(u => u.ID == inputID);
bool userExists = matchingUsers > 0;

or

bool userExists = dbContext.GetTable<User>().Any(u => u.ID == inputID);