Dapper Tutorial - Knowledge Base (KB)

AsyncQuery with postgresql and dapper using npqsql

I was trying dapper orm and recently they added asyncquery support. I googled it about that. It is wonderful if you have heavy traffic on your site. I was trying that with postgressql and dapper. Now, in connection if I am passing simple connection string...

Calling QueryAsync in Dapper throws a InvalidOperationException

I was trying out the async support in dapper and when running a simple use case I ran into the follow issue. I have an ApiController that just triggers a log entries using dapper to create it in the database. My db connections are fine. When I run a synch...

Using Async and Await to break up database call (with Dapper)

We're requesting thousands of objects back from Dapper and hit the parameter limit (2100) so have decided to load them in chunks....I thought it would be a good opportunity to try Async Await - this the first time I've had a go so maybe making a school bo...

cancellation token on Dapper

I'm using Dapper 1.31 from Nuget. I have this very simple code snippet,...string connString = ""; string query = ""; int val = 0; CancellationTokenSource tokenSource = new CancellationTokenSource(); using (IDbConnection conn = new SqlConnection(connString...

Using Async Await keywords with Dapper

I want to use a micro-orm and decided to go with Dapper. ...But can't seem to find any mentions of it supporting the new async/await syntax. Async queries are important for me....Can someone provide a code example of an async query being made with Dapper...

Code after await runs twice

i have been developing a Windows form application and for DB end i am using Dapper. The problem i am trying to solve is to execute a parametered stored procedure asynchronously so that my the execution of the application is not stopped and once the execut...

blocking main thread on async/await

I am trying to make my base repository class asynchronous and I am running into some trouble. I am using Dapper ORM in my C# application. ...Base method...protected async Task<List<T>> Read<T>(CommandDefinition cmd) { using(SqlConnection myCon = new S...

Why is TaskCanceledException thrown when using Dapper QueryAsync<T> without async/await?

Why does calling ....Result... on this method result in a TaskCanceledException:...public Task<IEnumerable<object>> GetAsync() { using (var conn = new SqlConnection("connectionString")) { return conn.QueryAsync<object>("select * from objec...

Async, await and Task with ToList

I am attempting to learn how to use await and async....I have a service layer, which has a reference data manager. My interface is:...public interface IReferenceDataService { Task<List<ReferenceItemDto>> GetAsync(ReferenceTypes type); } ..

SqlConnection not being disposed when using async

I have a project that has a Sql-Server database back end and Dapper as an ORM. I am attempting to use Dapper's ...QueryAsync()... method to get some data. Not only that, but the call to my repo is coming from inside several tasks that are called with a ....

How to deal with potential big numbers of Tasks using async/await?

I have an Azure Function that queries a database with Dapper and throws this exceptions sometimes:...System.InvalidOperationException: Invalid operation. The connection is closed....System.InvalidOperationException: The requested operation cannot be com...

C# Async Await not completing

I have what I think is a fairly basic flow in an asychronous web api controller. The code looks like the following:...public async Task<IHttpActionResult> Put([FromBody] ObjectType myObject) { if (!ModelState.IsValid) { return BadRequest(M...

Why did my async with ContinueWith deadlock?

I'm not after a solution here, more an explanation of what's going on.... I've refactored this code to prevent this problem but I'm intrigued why this call deadlocked. Basically I have a list of head objects and I need to load each ones details from a DB ...

Retrieving data from a database in the background while a dialog is loading

I'm using Dapper in a WPF application to retrieve data from a database for a couple of combobox lists. I'd like that retrieval to occur in the background; it will prevent a small delay when the user opens the first combo box....So I've done this:...priva...