Tutorial by Examples: n

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...

For types known at compile-time, use a generic parameter with Query<T>. public class Dog { public int? Age { get; set; } public Guid Id { get; set; } public string Name { get; set; } public float? Weight { get; set; } public int IgnoredProperty { get { return 1; } ...

You can also query dynamically if you leave off the generic type. IDBConnection db = /* ... */; IEnumerable<dynamic> result = db.Query("SELECT 1 as A, 2 as B"); var first = result.First(); int a = (int)first.A; // 1 int b = (int)first.B; // 2

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; ...

ConnectionMultiplexer conn = /* initialization */; var profiler = new ToyProfiler(); conn.RegisterProfiler(profiler); var threads = new List<Thread>(); var perThreadTimings = new ConcurrentDictionary<Thread, List<IProfiledCommand>>(); for (var i = 0; i < 16; i++) {...

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

using System.Data; using System.Linq; using Dapper; class Program { static void Main() { using (IDbConnection db = new SqlConnection("Server=myServer;Trusted_Connection=true")) { db.Open(); var result = db.Query<string>(&quo...

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...

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");

db.StringSet("key", 11021); int i = (int)db.StringGet("key"); Or using StackExchange.Redis.Extensions: db.Add("key", 11021); int i = db.Get<int>("key");

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 ...

Extension methods were introduced in C# 3.0. Extension methods extend and add behavior to existing types without creating a new derived type, recompiling, or otherwise modifying the original type. They are especially helpful when you cannot modify the source of a type you are looking to enhance. Ex...

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, ...