Question

I am trying use LINQ in a C# program to get information from a database. I have found a lot of examples showing basic to advanced queries, but I can’t find anything to get a basic database connection. See basic LINQ example below:

var adultNames = from person in people
                 where person.Age >= 18
                 select person.Name; 

I just can’t figure out how to get to a specific database table and return information out of it. I want to be able to connect to a db table and return some information out of it. Thanks!

Answer 1

Theres a very simple way to connect to a database although I suggest you read the app config afterwards and other parts of your project to see how it works.

In the menu strip go to Data -> Add New Data Source. From here pick database then entity data model. Follow the rest of the steps to create a datasource for your project.

In your program you can create an object of the datasource by using:

WhatYouCalledTheDataSource datasourceObject = new WhatYouCalledTheDataSource();

You can then make queries on this object by changing your first line of the query to:

var adultNames = from person in datasourceObject.people 

to get the data you want, once you have the query you can place the results into a list like:

List<string> queryResults = new List<string>();

queryResults.AddRange(adultNames);

bearing in mind that I basing on the thought that name would be a string.
You can also create lists based on tables like

var adultNames = from person ...
                 ...
                 select person;
List<people> queryResults = new List<people>();
queryResults.AddRange(adultNames);