Sqldatareader to object Cast<dynamic>; // You should call the Cast method. ExecuteReader() method, do I need to put the reader inside a using. Oct 16, 2014 · In the first code snippet, we saw how we fetched a SqlDataReader that represented a ClientEntity instance. The application code must use it to load the results and then construct the objects and place them in a list. It's concepts are the underpinning to data conversions in Dapper, and can easily be used to map your own DataReader to an object (should you not want to use Dapper). The issue with caching the result of GetOrdinal applies to using reader["field_a"] as well, but this is often a micro-optimisation when reading through large datasets, and for me the improved readability trumps using a cast and worrying about the cached ordinal in Oct 16, 2009 · Its usage is pretty much the same as with regular object-to-object mapping using AutoMapper. Jul 29, 2009 · @Korey I've used this pattern in a few other places here on Stack Overflow, where the difference is that instead of accepting a datareader as an argument to a function, I would change the code at the location where the datareader is first created to return an IEnumerable instead of datareader or something else. Creating a Simple C# SqlDataReader object mapper. Dec 10, 2019 · private SqlDataReader executeReader(SqlCommand command) { var refCountdr = (RefCountingDataReader) sqlHelper. Jul 28, 2014 · I have implemented the code to convert datareader to list of objects. // The reader is typically closed in the method. In that function, we saw how the code mapped each of the SqlDataReader columns to each of the properties on our custom . NET) over a stream. Below is an extension method converting a SqlDataReader into something of type T: See full list on learn. By structuring your data retrieval process with object-oriented principles, you can streamline your development workflow and ensure a more robust and scalable application architecture. Suppose we have a view object like the one shown below: public class SomeView { public Int32 SomeNumber { get; private set; } public Guid AnId { get; private set; } public Double OrNothing { get; private set; } } Sep 16, 2024 · To retrieve data using a DataReader, create an instance of the Command object, and then create a DataReader by calling Command. NET/C# SqlDataReader rdr = cmd. ExecuteReader(); You use the Read method of the DataReader object to obtain a row from the results of the query. g. Nov 15, 2023 · I have a SQL Server 2008 database and I am working on it in the backend. NET Framework 4. To create a SqlDataReader, you must call the ExecuteReader method of the SqlCommand object, instead of directly using a constructor. Here is the revised code that now implements our mapping class. While the SqlDataReader is being used, the associated SqlConnection is busy serving the SqlDataReader , and no other operations can be performed on the SqlConnection other than closing it. ExecuteReader(cmd); return (SqlDataReader) refCountdr. In the example below, we access the data from the SqlDataReader object using the index number. in CustomerEntity class, I have CustomerId and CustomerName prope Feb 2, 2012 · How can I map a DataReader object into a class object by using generics? For example I need to do the following: public class Mapper&lt;T&gt; { public static List&lt;T&gt; MapObject( Jul 27, 2015 · // If you simply assign reader object itself as the data you wont be // able to get data once the reader or connection is closed. Emit; namespace Improve. NET. com To create a SqlDataReader, you must call the ExecuteReader method of the SqlCommand object, instead of directly using a constructor. – Super fast mapping DataReader to a strongly typed object. One deficiency with Entity Framework is the ability to load data from a stored procedure or a direct query when the column names don’t match your model property names exactly. Object-to-object mappers are designed for mapping between closely aligned, strongly-typed, data-containing classes, usually to save hand-writing mapping code. Supports simple property mapping, property name transformations, string trimming, manual property binding by name, type changing, function binding, etc. Sep 2, 2009 · Apparently, ever since . And you should too. Framework. NET objects, each data provider has a data reader class. Jan 2, 2017 · Populating Entity Framework Models with SqlDataReader. The argument is that: Since the SqlDataReader dr object is NOT A NEW OBJECT LIKE THE connection or command objects, its simply a reference pointing to the cmd. ExecuteReader(); The ExecuteReader method of the SqlCommand object, cmd, returns a SqlDataReader instance. Collections. Data. My intention was to not to use column name string literals while reading the datareader. You must callExecuteReader on a command object, like this: SqlDataReader rdr = cmd. Allows you to map a SqlDataReader to the particular objects. Reflection; using System. Lets show a very simple example. Sep 23, 2009 · I have data in a DataReader which I want to be converted to a List&lt;T&gt;. What is a possible simple solution for this? For e. Aug 7, 2024 · In conclusion, converting data from a SqlDataReader to an object in C# is a fundamental aspect of data handling in database applications. Allows you to map a SqlDataReader to the particular class. NET ClientEntity class. The following code uses a JsonWriter (from JSON. Similar to other ADO. Data { public class EntityMapper { private delegate T mapEntity<T>(DbDataReader dr); private static Dictionary<Type, Delegate> cachedMappers = new Dictionary<Type, Delegate>(); public After creating an instance of the Command object, you create a DataReader by calling Command. Hot Network Questions Speciation while populating a planet from a colony ship How can I assert myself and earn Apr 13, 2015 · @nawfal This approach handles the DBNull issue the OP posted about and when defined as extension methods they read better (IMHO). Similarly, SqlDataReader and ODBC DataReader are data reader classes for SQL and ODBC data providers, respectively. It can't be converted to any container type. Simple C# SqlDataReader object mapper. Reflection. GetValues(data); This populates data with the values of the current reader row, assigning into size the number of objects that were put into the array. High performance, lighweight (12Kb dll), uses AOT source generation and no reflection, mapping code is generated at compile time. For example; OleDbDataReader is the data reader class for OleDb data providers. Getting an instance of a SqlDataReader is a little different than the way you instantiate other ADO. ExecuteReader to retrieve rows from a data source. Oct 19, 2015 · When it comes to mapping I would probably introduce a convention where sub objects are mapped using an alternative method in the mapping interface: public interface IEntityMapper { object Map(IDataRecord record); object Map(IDataRecord record, string prefix); } The DataReader class represents a data reader in ADO. NET objects. NET docs, eg in Retrieving data using a DataReader: Jan 13, 2016 · I think you are using the wrong class of tool (object-to-object mappers) for the task at hand (object-relational mapping). Data = reader. public static IEnumerable&lt;T&gt; using System; using System. This is described in the ADO. Common; using System. ExecuteReader(); while (rdr. microsoft. Benchmarks Jun 7, 2016 · Creating a SqlDataReader Object. May 13, 2022 · SqlDataReader isn't a container, it's a cursor used to load data. posted on January 2, 2017 by long2know in ASP. ExecuteReader to retrieve rows from a data source, as shown in the following example. NET 1. InnerReader; } As you have realized by now, you should know what is coming next about building the model to populate the collection. Example to Understand SqlDataReader in C#. The DataReader provides an unbuffered stream of data that allows procedural logic to efficiently process results from a data source sequentially. Feb 22, 2011 · I encounter use cases where the number of rows being returned by the data reader may become problematic with respect to memory consumption. Generic; using System. Here, the index is starting Sep 16, 2024 · To retrieve data using a DataReader, create an instance of the Command object, and then create a DataReader by calling Command. Read()) { //how do I read Aug 1, 2015 · Convert SqlDataReader to object for . . Note: The DataReader object increases the performance of the application as well as reduces the system overheads, and the reason for this is one row at a time is stored in memory. SqlDataReader myReader = myCommand. 1 SqlDataReader had the following method: int size; object[] data = new object[]{}; size = reader. I am working on ASP. NET, Entity Framework. xfwzb cgzhqy nln oujyt ldekb jpw vzcsb hwxqoefq umdm qwlltp fkoca rgkk sgwmm isejygv eicy