是否可以从DataContext.ExecuteQuery返回IEnumerable匿名对象? [英] Is it possible to return IEnumerable of anonymous objects from DataContext.ExecuteQuery?

问题描述

我开发了一个报告引擎，其中的报告基于模板.每个模板都有带SQL查询的字符串，每个报表都有SQL查询参数的特定值.为了呈现报告，我设置了参数并调用 DataContext .ExecuteQuery 方法获取记录列表.但是要捕获返回的列，我必须知道它们的名称，并有一个具有相应属性的类.

I develop a reporting engine where reports are based on templates. Every template has string with SQL query and every report has specific values for SQL query parameters. To render a report I set parameters and call DataContext.ExecuteQuery method to get list of records. But to catch returned columns I have to know their names and have a class with corresponding properties.

是否有可能以某种方式从DataContext.ExecuteQuery返回IEnumerable匿名对象，然后使用Reflection确定它们的属性?

Is it possible somehow to return IEnumerable of anonymous objects from DataContext.ExecuteQuery and then determine their properties using Reflection?

我需要 SqlDataReader的LINQ等效项.GetValues .

谢谢！

推荐答案

在我们使用带有dynamiс关键字的C#4.0之前，我们可以使用此解决方案(文章

Until we have C# 4.0 with dynamiс keyword we can use this solution (slightly modified code from an article Executing arbitrary queries in LINQ to SQL by Octavio Hernández Leal):

public static class DataContextExtension
{
    public static IEnumerable<Dictionary<string, object>> ExecuteQuery(this DataContext dataContext, string query)
    {
        using (DbCommand command = dataContext.Connection.CreateCommand())
        {
            command.CommandText = query;
            dataContext.Connection.Open();

            using (DbDataReader reader = command.ExecuteReader(CommandBehavior.CloseConnection))
            {
                while (reader.Read())
                {
                    Dictionary<string, object> dictionary = new Dictionary<string, object>();

                    for (int i = 0; i < reader.FieldCount; i++)
                        dictionary.Add(reader.GetName(i), reader.GetValue(i));

                    yield return dictionary;
                }
            }
        }
    }
}

此扩展方法返回IEnumerable of Dictionary<>对象，其中键是查询列的名称.

This extension method returns IEnumerable of Dictionary<> objects where keys are names of query columns.

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