C＃Dapper-在QueryAsync方法上使用linq [英] c# Dapper - using linq on QueryAsync method

问题描述

当在queryAsync上正常工作时，为什么不能在queryAsync上使用.select？
例如，在这里.select对我大吼，告诉我它无法解析符号 select：

Why can't I use .select on a queryAsync when it works fine on Query? For example, here the .select yells at me telling me it cant resolve the symbol "select":

var result = await sqlConnection.QueryAsync<Product>(procedure,
                            commandType: CommandType.StoredProcedure).Select(p => new Product
                        {
                            Code= (string)p.fldCode,
                            Name=(string)p.fldName
                            });

但是一旦我更改为Query，它就不会再大喊大叫了。如果有问题，则无法从sp中解析fldCode列：

but as soon as i change to Query, it doesn't yell anymore. if anything it has trouble resolving the fldCode columns from the sp:

 var result = sqlConnection.Query<Product>(procedure,
                                commandType: CommandType.StoredProcedure).Select(p => new Product
                            {
                                Code= (string)p.fldCode,
                                Name=(string)p.fldName
                                });

这是为什么？

我在这里问了一个先前的问题将C＃Dapper映射列映射到实体属性-无法解析符号'Select''

I asked a previous question here C# Dapper mapping columns to entity properties - "Cannot resolve symbol 'Select'"

推荐答案

异步方法返回Task（基本上是占位符的最终结果）异步操作）。您需要等待它以获取实际值

Async methods return a Task (basically a placeholder for the eventual result of the async action). You need to await it to get the actual value

var result = (await sqlConnection.QueryAsync<Product>(
                 procedure,
                 commandType: CommandType.StoredProcedure
             )).Select(p => new Product
                {
                    Code= (string)p.fldCode,
                    Name=(string)p.fldName
                 }
             );

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