Dapper Tutorial - Knowledge Base (KB)
100 results
Using Visual Studio and Dapper, how do I use a connection string?
I am trying to get a Connection String set up in my .Net Core application but i keep getting the error:...System.NullReferenceException: 'Object reference not set to an instance of an object.'...I have tried adding the following to ...appsettings.json...:...
asked by JoeG
After execute a Dapper query, how to I map a master/detail entity?
At work, we're considering using ...Dapper.... In the existing code base, our master/detail objects are loaded separately. Typically, this means that there is one sql statement executed for all master records and one sql statement executed per detail reco...
asked by Mitkins
In a single query result using Dapper, how do I get the DapperRow?
I've done the following SQL query:...SELECT SUM(SI.UnitaryValue) as Amount FROM Services as S INNER JOIN ServicesItems as SI ON S.ServiceId = SI.ServiceId WHERE S.ServiceId = @ID" ...In the query: Services has a collection of Service Items. Then...
asked by Paulo MaurÃcio
How in Dapper I pass argument to a select query in an Oracle database?
I'm trying to pass parameters to Dapper for a select query in an Oracle database, but somehow, it doesn't work with the ":" identifier....It works fine using string concatenation :...string req = "SELECT * FROM contact WHERE code_comite = '"; req ...
asked by user7191279
How to return a list of string from a Dapper query?
Is there any way to get a simple list of strings from a Dapper Query? I don't want to create an object that contains all my field names by type. My query returns one row of data. Sometimes with 2 columns other times with 5 or 20 or 100 and I just want all...
asked by Ed R.
Is there some Dapper extension that allow to bind properties to database column name?
I have the following challenge with this class:...Public Class MyClass Property Id As Integer Property LastName as String End Class ...The corresponding data table in the database has as fields: ...Id (int, not null)...Last-Name (nvarchar(80),nul...
asked by Dabblernl
When I execute my sp GetAllUsers in Dapper, why do I get a sequence contains no matching element error?
Hello my question is I have 2 table one is User table the other one is CustomerUsers I select them by Deleted=0 When I try to list all users and have customerId, I am having issue that sequence contains no matching element error... My Code is below any he...
asked by phantasmagoria1985
Why I get a connection timeout error when using async / await with Dapper?
We're running into an issue were we execute a large number of queries at once (large being 100-200) using Dapper async and end up getting timeout exceptions. I think what is happening is that Dapper is doing ...await ... [connection].OpenAsync(...)... (..
asked by Letseatlunch
Using a stored procedure, how with Dapper can I insert many rows into two tables?
I am using Dapper (...https://github.com/StackExchange/Dapper...) in asp.net core myweb api project. I have a requirement to create a master record and insert a set of rows into a child table....Ex. OrdersMaster table create an order id in this table ...
asked by blue
Is it possible to insert many rows in a single query using Dapper?
Does ...StackExchange.Dapper... support the following SQL syntax?...INSERT INTO MyTable (a, b, c) VALUES (1, 2, 3), (4, 5, 6), (7, 8, 9); ...I've seen some examples where you can pass in a List to be inserted but the descriptions I've seen suggest i...
asked by Joe Phillips
How with Dapper to get data from a INNER JOIN sql?
I am working on DB operations on one project and developing WinForms App C# and I am using Dapper to get data out of DB, I am stuck at situation where I need to retrieve data using inner join. Eg. I've two tables Authors and Book as Follow : ...public cla...
asked by Infii
How can I use the Dapper with a list to create an IN statement for the WHERE clause?
I'm passing an int list to Dapper Where IN clause. I get error because it is and comma-separated string....JObject step1Form = JObject.Parse(Request.Cookies["step1"]); IList<int> step1List = step1Form.Root.Select(c => (int)c).ToList(); // "1, 22, 31, 45,...
asked by dsub camfx
Why do I get a "'The reader has been disposed' error" error when using Dapper multiple query?
I have written stored procedure which return two result sets. and I have called stord procedure from C# code by dapper API...like this ...var Count= result.Read<int>().ToList().FirstOrDefault(); var Employees= result.Read<EmployeeData>().ToList(); ...the ...
asked by Rajiv
How to use a dynamic list to filter a query in Dapper?
I have a c# mvc app using Dapper. There is a list table page which has several optional filters (as well as paging). A user can select (or not) any of several (about 8 right now but could grow) filters, each with a drop down for a from value and to valu...
asked by nurdyguy
How to use Dapper to insert data into a PostgreSQL jsonb column?
I'm trying to insert JSON data into a JSONB PostgreSQL column using Dapper.Net....The ...NPGSQL Documentation for JSONB... gives specific instructions to use the ...NpgsqlDbType.Jsonb... datatype....With Dapper, I'm trying to add this as a custom paramete...
asked by Damien Sawyer
How to get output from a stored procedure when using Dapper?
I just started learning Dapper in C# but I am having difficulty in executing stored procedures with two or more SQL Statements in one transaction....How do you get the output parameter of a Stored Procedure that contains both Insert and Select statement...
asked by thecodeexplorer
How to return dynamic values in C# Dapper?
I have a query where I am returning dynamic data and am unable to retrieve the values through Dapper as listed in their documentation (...https://github.com/StackExchange/Dapper...)....They have a sample of code like so,...var rows = connection.Query("sel...
asked by Zac
In Dapper, how to get the SQL Exception number when an error occurs?
My stored procedure is throwing custom errors to handle validation within a multi user web app. This is working as expected in SQL Server with error number 50001 being returned however when my C# code catches the error it always has the error number 50000...
asked by OjM
How with Dapper to insert in a temproary table?
I am trying to insert a List of integers into a temporary table using Dapper. I wrote my query based on the selected answer to this Stack Overflow ...question.... However, I get a syntax error when running the query....Code:...List<int> lst = new List<int...
asked by Drob337
What is the best way to convert DapperRow to Dictionary<string,string> in Dapper?
I've a method that returns IEnumerable with Dapper Row. ...But I'm trying to access the data without typecasting it to a particular class and I'm getting null value.
asked by ThejaSingireddy
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