ExecuteReader 不支持 MultiExec

Question

我有以下代码：

let getByIdAsync (connectionString : string) (id : int) = 
        let sql = @"SELECT * FROM [User] WHERE [Id] = @id"
        let args = [ "id" => id ]

        async {
            use connection = new SqlConnection(connectionString)
            do! connection.OpenAsync() |> Async.AwaitTask

            try
                use! reader = connection.ExecuteReaderAsync(sql, args) |> Async.AwaitTask
                return reader |> mapRowsToRecords |> Seq.head
            with
            | e -> return Error e.Message
        }

此代码抛出 MultiExec is not supported by ExecuteReader，我不知道为什么。其他查询（例如我的插入）工作正常。我做错了什么？

Answer 1

我知道哪里不对了，字典前少了dict:

let getByIdAsync (connectionString : string) (id : int) = 
        let sql = @"SELECT * FROM [User] WHERE [Id] = @id"
        let args = dict [ "id" => id ] // added dict

        async {
            use connection = new SqlConnection(connectionString)
            do! connection.OpenAsync() |> Async.AwaitTask

            try
                use! reader = connection.ExecuteReaderAsync(sql, args) |> Async.AwaitTask
                return reader |> mapRowsToRecords |> Seq.head
            with
            | e -> return Error e.Message
        }

查看 this article 了解更多信息。