你可以试试这个:

 string sql = "UPDATE Customer SET City = @City WHERE CustomerId = @CustomerId";             
 conn.Execute(sql, customerEntity);

下面是一个关于Repository Pattern的简单例子:

public interface IUserRepository
{
    Task<bool> CreateUser(User user);
    Task<bool> UpdateUser(User user);
}

在UserRepository中:

public class UserRepository: IUserRepository
    {
        private readonly IConfiguration _configuration;

        public UserRepository(IConfiguration configuration)
        {
            _configuration = configuration;
        }

        public async Task<bool> CreateUser(User user)
        {
            using var connection = new NpgsqlConnection(_configuration.GetValue<string>("DatabaseSettings:ConnectionString"));

            var affected =
                await connection.ExecuteAsync
                    ("INSERT INTO User (Name, Email, Mobile) VALUES (@Name, @Email, @Mobile)",
                            new { Name= user.Name, Email= user.Email, Mobile = user.Mobile});

            if (affected == 0)
                return false;

            return true;
        }

        public async Task<bool> UpdateUser(User user)
        {
            using var connection = new NpgsqlConnection(_configuration.GetValue<string>("DatabaseSettings:ConnectionString"));

            var affected = await connection.ExecuteAsync
                    ("UPDATE User SET Name=@Name, Email= @Email, Mobile = @Mobile WHERE Id = @Id",
                            new { Name= user.Name, Email= user.Email, Mobile  = user.Mobile , Id = user.Id });

            if (affected == 0)
                return false;

            return true;
        }
    }

注意:NpgsqlConnection用于获取PostgreSQL数据库的ConnectionString

使用Dapper执行CRUD操作是一项简单的任务。我已经提到了下面的示例，它们应该可以帮助您进行CRUD操作。

CRUD代码:

方法#1:当您插入来自不同实体的值时使用此方法。

using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
    string insertQuery = @"INSERT INTO [dbo].[Customer]([FirstName], [LastName], [State], [City], [IsActive], [CreatedOn]) VALUES (@FirstName, @LastName, @State, @City, @IsActive, @CreatedOn)";

    var result = db.Execute(insertQuery, new
    {
        customerModel.FirstName,
        customerModel.LastName,
        StateModel.State,
        CityModel.City,
        isActive,
        CreatedOn = DateTime.Now
    });
}

方法#2:当您的实体属性与SQL列具有相同的名称时使用此方法。因此，Dapper作为ORM将实体属性与匹配的SQL列映射。

using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
    string insertQuery = @"INSERT INTO [dbo].[Customer]([FirstName], [LastName], [State], [City], [IsActive], [CreatedOn]) VALUES (@FirstName, @LastName, @State, @City, @IsActive, @CreatedOn)";

    var result = db.Execute(insertQuery, customerViewModel);
}

CRUD代码:

using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
    string selectQuery = @"SELECT * FROM [dbo].[Customer] WHERE FirstName = @FirstName";

    var result = db.Query(selectQuery, new
    {
        customerModel.FirstName
    });
}

CRUD代码:

using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
    string updateQuery = @"UPDATE [dbo].[Customer] SET IsActive = @IsActive WHERE FirstName = @FirstName AND LastName = @LastName";

    var result = db.Execute(updateQuery, new
    {
        isActive,
        customerModel.FirstName,
        customerModel.LastName
    });
}

CRUD代码:

using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
    string deleteQuery = @"DELETE FROM [dbo].[Customer] WHERE FirstName = @FirstName AND LastName = @LastName";

    var result = db.Execute(deleteQuery, new
    {
        customerModel.FirstName,
        customerModel.LastName
    });
}

使用短小精悍的。它是如此简单:

插入列表:

public int Insert(IEnumerable<YourClass> yourClass)
{
    using (SqlConnection conn = new SqlConnection(ConnectionString))
    {
        return conn.Insert(yourClass) ;
    }
}

插入单:

public int Insert(YourClass yourClass)
{
    using (SqlConnection conn = new SqlConnection(ConnectionString))
    {
        return conn.Insert(yourClass) ;
    }
}

更新列表:

public bool Update(IEnumerable<YourClass> yourClass)
{
    using (SqlConnection conn = new SqlConnection(ConnectionString))
    {
        return conn.Update(yourClass) ;
    }
}

更新单:

public bool Update(YourClass yourClass)
{
    using (SqlConnection conn = new SqlConnection(ConnectionString))
    {
        return conn.Update(yourClass) ;
    }
}

来源:https://github.com/StackExchange/Dapper/tree/master/Dapper.Contrib

你可以试试这个:

 string sql = "UPDATE Customer SET City = @City WHERE CustomerId = @CustomerId";             
 conn.Execute(sql, customerEntity);

我们正在考虑构建一些助手，仍然决定api，如果这是在核心或不。详见:https://code.google.com/archive/p/dapper-dot-net/issues/6。

与此同时，你可以做以下事情

val = "my value";
cnn.Execute("insert into Table(val) values (@val)", new {val});

cnn.Execute("update Table set val = @val where Id = @id", new {val, id = 1});

等等

请参见我的博客文章:恼人的插入问题

更新

正如评论中指出的，现在在Dapper中有几个可用的扩展。以以下IDbConnection扩展方法的形式贡献项目:

T Get<T>(id);
IEnumerable<T> GetAll<T>();
int Insert<T>(T obj);
int Insert<T>(Enumerable<T> list);
bool Update<T>(T obj);
bool Update<T>(Enumerable<T> list);
bool Delete<T>(T obj);
bool Delete<T>(Enumerable<T> list);
bool DeleteAll<T>();