Tutorial by Examples: l

Either search in the Visual Studio GUI: Tools > NuGet Package Manager > Manage Packages for Solution... (Visual Studio 2015) Or run this command in a Nuget Power Shell instance to install the latest stable version Install-Package Dapper Or for a specific version Install-Package Dapper...

class ToyProfiler : IProfiler { public ConcurrentDictionary<Thread, object> Contexts = new ConcurrentDictionary<Thread, object>(); public object GetContext() { object ctx; if(!Contexts.TryGetValue(Thread.CurrentThread, out ctx)) ctx = null; ...

IDBConnection db = /* ... */ var id = /* ... */ db.Execute(@"update dbo.Dogs set Name = 'Beowoof' where Id = @id", new { id });

LINQPad is great for testing database queries and includes NuGet integration. To use Dapper in LINQPad press F4 to open the Query Properties and then select Add NuGet. Search for dapper dot net and select Add To Query. You will also want to click Add namespaces and highlight Dapper to include the Ex...

public class IHtmlStringTypeHandler : SqlMapper.TypeHandler<IHtmlString> { public override void SetValue( IDbDataParameter parameter, IHtmlString value) { parameter.DbType = DbType.String; parameter.Value = value?.ToHtmlString(); } pu...

To fetch multiple grids in a single query, the QueryMultiple method is used. This then allows you to retrieve each grid sequentially through successive calls against the GridReader returned. var sql = @"select * from Customers where CustomerId = @id select * from Orders where Cust...

Dapper makes it easy to follow best practice by way of fully parameterized SQL. Parameters are important, so dapper makes it easy to get it right. You just express your parameters in the normal way for your RDBMS (usually @foo, ?foo or :foo) and give dapper an object that has a member called foo...

Sometimes the convenience of a parameter (in terms of maintenance and expressiveness), may be outweighed by its cost in performance to treat it as a parameter. For example, when page size is fixed by a configuration setting. Or a status value is matched to an enum value. Consider: var orders = conn...

A common scenario in database queries is IN (...) where the list here is generated at runtime. Most RDBMS lack a good metaphor for this - and there is no universal cross-RDBMS solution for this. Instead, dapper provides some gentle automatic command expansion. All that is requires is a supplied para...

Sometimes, you want to do the same thing multiple times. Dapper supports this on the Execute method if the outermost parameter (which is usually a single anonymous type, or a domain model instance) is actually provided as an IEnumerable sequence. For example: Order[] orders = ... // update the tot...

All values in Redis are ultimately stored as a RedisValue type: //"myvalue" here is implicitly converted to a RedisValue type //The RedisValue type is rarely seen in practice. db.StringSet("key", "aValue");

In ADO.NET, correctly handling null is a constant source of confusion. The key point in dapper is that you don't have to; it deals with it all internally. parameter values that are null are correctly sent as DBNull.Value values read that are null are presented as null, or (in the case of mapping...

Open Visual Studio In the toolbar, go to File → New Project Select the Console Application project type Open the file Program.cs in the Solution Explorer Add the following code to Main(): public class Program { public static void Main() { // Prints a message to the conso...

using System; class Program { // The Main() function is the first function to be executed in a program static void Main() { // Write the string "Hello World to the standard out Console.WriteLine("Hello World"); } } Console.WriteLine has se...

string fullOrRelativePath = "testfile.txt"; string fileData; using (var reader = new StreamReader(fullOrRelativePath)) { fileData = reader.ReadToEnd(); } Note that this StreamReader constructor overload does some auto encoding detection, which may or may not conform to the ...

C# allows user-defined types to overload operators by defining static member functions using the operator keyword. The following example illustrates an implementation of the + operator. If we have a Complex class which represents a complex number: public struct Complex { public double Real ...

Extension methods can also be used like ordinary static class methods. This way of calling an extension method is more verbose, but is necessary in some cases. static class StringExtensions { public static string Shorten(this string text, int length) { return text.Substring(0, ...

Initialize a collection type with values: var stringList = new List<string> { "foo", "bar", }; Collection initializers are syntactic sugar for Add() calls. Above code is equivalent to: var temp = new List<string>(); temp.Add("foo"); temp.A...

Equals Checks whether the supplied operands (arguments) are equal "a" == "b" // Returns false. "a" == "a" // Returns true. 1 == 0 // Returns false. 1 == 1 // Returns true. false == true // Returns false. false == false // Return...

var multiLine = @"This is a multiline paragraph"; Output: This is a multiline paragraph Live Demo on .NET Fiddle Multi-line strings that contain double-quotes can also be escaped just as they were on a single line, because they are verbatim strings. var multilineWithDoubleQ...