(I'm not sure if that is official documentation or not)
But Dapper.Contrib does not honor that. It throws an System.InvalidCastException in line 834 in SqlMapperExtensions:
public int Insert(IDbConnection connection, IDbTransaction transaction, int? commandTimeout, string tableName, string columnList, string parameterList, IEnumerable<PropertyInfo> keyProperties, object entityToInsert)
{
var cmd = $"insert into {tableName} ({columnList}) values ({parameterList});select SCOPE_IDENTITY() id";
var multi = connection.QueryMultiple(cmd, entityToInsert, transaction, commandTimeout);
var first = multi.Read().FirstOrDefault();
if (first == null || first.id == null) return 0;
var id = (int)first.id;
var propertyInfos = keyProperties as PropertyInfo[] ?? keyProperties.ToArray();
if (propertyInfos.Length == 0) return id;
var idProperty = propertyInfos[0];
idProperty.SetValue(entityToInsert, Convert.ChangeType(id, idProperty.PropertyType), null);
return id;
}
Exception
System.InvalidCastException: Invalid cast from 'System.Int32' to 'DapperInsertKey.Program+Key'.
at System.Convert.DefaultToType(IConvertible value, Type targetType, IFormatProvider provider)
at SqlServerAdapter.Insert(IDbConnection connection, IDbTransaction transaction, Nullable`1 commandTimeout, String tableName, String columnList, String parameterList, IEnumerable`1 keyProperties, Object entityToInsert) in /_/Dapper.Contrib/SqlMapperExtensions.cs:line 834
at Dapper.Contrib.Extensions.SqlMapperExtensions.Insert[T](IDbConnection connection, T entityToInsert, IDbTransaction transaction, Nullable`1 commandTimeout) in /_/Dapper.Contrib/SqlMapperExtensions.cs:line 377
at DapperInsertKey.Program.Main(String[] args) in D:\users\yecarri\source\repos\DapperInsertKey\DapperInsertKey\Program.cs:line 31
Code
using Dapper;
using Dapper.Contrib.Extensions;
using Microsoft.Data.SqlClient;
using System.Data;
namespace DapperInsertKey
{
internal class Program
{
static void Main(string[] args)
{
SqlMapper.AddTypeHandler(new KeyTypeHandler());
using (var connection = new SqlConnection("server=.;database=equus;integrated security=true;Encrypt=false"))
{
connection.Open();
connection.Execute(@"
If not exists (select TABLE_NAME from information_schema.TABLES t
where t.TABLE_SCHEMA='dbo' AND TABLE_NAME= 'User')
CREATE TABLE dbo.[User](
UserId int identity(1,1) primary key clustered,
[UserName] [varchar](120) NOT NULL
)");
connection.Execute("TRUNCATE TABLE dbo.[User]");
var user = new User() { UserName="OSO" };
connection.Insert(user);
connection.Close();
}
}
public struct Key
{
private readonly int _value;
public Key(int value) { _value = value; }
public static implicit operator Key(int value) { return new Key(value); }
public static implicit operator int(Key key) { return key._value; }
}
[Table("dbo.[User]")]
public class User
{
[Key]
public Key UserId { get; set; }
public string UserName { get; set; } = "";
}
public class KeyTypeHandler : SqlMapper.TypeHandler<Key>
{
public override Key Parse(object value)
{
return new Key((int)value);
}
public override void SetValue(IDbDataParameter parameter, Key value)
{
parameter.Value = (int)value;
}
}
}
}
SqlMapper.TypeHandler
is intended to support custom types in entities. It's documented here:https://medium.com/dapper-net/custom-type-handling-4b447b97c620
(I'm not sure if that is official documentation or not)
But Dapper.Contrib does not honor that. It throws an System.InvalidCastException in line 834 in SqlMapperExtensions:
Exception
Code