如何使用摘要从当前类中获取属性？

Question

Is it possible for me to create a snippet and have it analyze a current class, get the properties of said class, and then create a sql function that writes out line by line each property in a command parameter.

What I am looking for is doing something like this:

public static int Add(MyObject Message) {
        MySqlConnection connection = new MySqlConnection(MySqlConnection);
        MySqlCommand command = new MySqlCommand("Add_Message", connection);
        command.CommandType = CommandType.StoredProcedure;
        command.Parameters.AddWithValue("@IMFromUserID", Message.IMFromUserID);
        command.Parameters.AddWithValue("@IMToUserID", Message.IMToUserID);
        command.Parameters.AddWithValue("@IMMessage", Message.IMMessage);
        command.Parameters.AddWithValue("@IMTimestamp", Message.IMTimestamp);
        connection.Open();
        MySqlDataReader reader = command.ExecuteReader();
        while (reader.Read()) {
            Message.IMID = (int)reader["IMID"];
        }
        command.Dispose();
        connection.Close();
        connection.Dispose();
        return Message.IMID;
    }

Basically I want the snippet to populate the entire Add function and fill in the @PropertyName and the Message.PropertyName in the command.Parameters.AddWithValue

Answer 1

I don't think code snippets are powerful enough. Maybe the ReSharper's code templates are powerful enough but I don't think so, too. You could look into using T4 templates if you really need or want code generation.

Personally I would suggest to avoid compiletime code generation altogether. You could use reflection - easy but slow - or runtime code generation - complex but fast. If performance is not a primary concern I suggest to use reflection.

 public static Int32 Add<TMessage>(TMessage message)
     where TMessage: IMessageWithIMID
 {
    using (var connection = new MySqlConnection(connectionString))
    using (var command = new MySqlCommand("Add_Message", connection))
    {
        command.CommandType = CommandType.StoredProcedure;

        // We look only at public instance properties but you can easily
        // change this and even use a custom attribute to control which
        // properties to include.
        var properties = typeof(TObject).GetProperties(BindingFlags.Public |
                                                       BindingFlags.Instance);

        foreach (var property in properties)
        {
            var parameterName = "@" + property.Name;

            var value = property.GetValue(message, null);

            command.Parameters.AddWithValue(parameterName, value);
        }

        connection.Open();

        message.IMID = (Int32)command.ExecuteScalar();

        return message.IMID;
    }
}

Note that you have to introduce and implement the interface IMessageWithIMID in order to access the property IMID .

internal interface IMessageWithIMID
{
    Int32 IMID { get; set; }
}

Note that you also don't need a data read - you can just use ExecuteScalar() . This turns

using (var reader = command.ExecuteReader())
{
    while (reader.Read())
    {
        message.IMID = (Int32)reader["IMID"];
    }
}

into

message.IMID = (Int32)command.ExecuteScalar();

and you are done.