How to initilize a var that is going to be used for storing query result

Question

0.00/5 (No votes)

See more:

I am sorry for this simple question! How to initilize a var that is going to be used for storing query result (db.query(...) or db.querysingle(...))?

C#

var queryResult;

This code will cause error because the var is not initilized. And when I give it null value I get this error:
Cannot assign null to an implicitly-typed local variable

Posted 28-Dec-12 3:20am

cs101000

Add a Solution

Comments

Sandeep Mewara 28-Dec-12 9:24am

Query result is what format - String? Datatable? What?

cs101000 28-Dec-12 10:27am

queryResult is a single row returned by db.querysingle(...) or a set of rows returned by db.query(...) where db is a webmatrix DataBase. And this var is going to be fetched for getting its columns (and rows if any) like what people do in webmatrix. I just wana initilize it with a dummy value and then use it later when executing a query.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Gianmaria Gregori · Answer 1 · 2013-01-03T13:02:00

Solution 2

It depends on the query type.
If you use the Database.Query method, you can initialize the variable as

IEnumerable<dynamic> queryResult = null;

Otherwise, if you use the Database.QuerySingle method, the best way is

dynamic queryResult = null;

Posted 3-Jan-13 13:02pm

Gianmaria Gregori

Zafar Sultan · Answer 2 · 2012-12-28T03:31:00

Solution 1

Var is an implicit type. So, you will have to assign it value where you declare it. It aliases any type in the C# programming language. The aliased type is determined by the C# compiler. You can not assign null to it.

Posted 28-Dec-12 3:31am

Zafar Sultan

Comments

cs101000 28-Dec-12 10:29am

I know that. So I wana initilize it with something else just to prevent the error "Implicitly-typed local variables must be initialized"

Zafar Sultan 28-Dec-12 10:36am

I don't know why there is a desperate need to declare it before using? Maybe you have some sort of scenario. But if you have to, then declare a list, initialize it with dummy data and then assign that list to your variable. That is the only way I can think of to "prevent the error". If that's all you want to do.