Question

如何将下面的查询结果转换为List<Product>类型？只想返回一些结果并将其分配给products变量：

using (SqlConnection sqlConnection = new SqlConnection(LOCAL))
{
    sqlConnection.Open();
    using (SqlCommand cmd = sqlConnection.CreateCommand())
    {
        cmd.CommandText = "select Sku from product";
        cmd.CommandType = CommandType.Text;
        using (SqlDataReader reader = cmd.ExecuteReader()) // ????
        {
            // ??????????
        }
    }
}

var products = new List<Product>();

我需要products变量来包含结果。如何才能做到这一点？

Answer 1

在调用数据库之前创建列表并创建新的产品对象并映射它。

var products = new List<Product>();
using (SqlConnection sqlConnection = new SqlConnection(LOCAL))
{
  sqlConnection.Open();
  using (SqlCommand cmd = sqlConnection.CreateCommand())
  {
   cmd.CommandText = "select Sku from product;
   cmd.CommandType = CommandType.Text;
   using (SqlDataReader reader = cmd.ExecuteReader()) ????
   {
    var product = new Product();
    //Grab the values using the SqlDataReader and map it to the properties
    //...
    //Add code e.g. product.Id = reader.GetField<int>("Id");
    //...
    products.Add(product);
   }
  }
}

Answer 2

创建存储产品的列表
根据DataReader

将每个产品添加到列表中

var products = new List<Product>();

using (SqlDataReader reader = cmd.ExecuteReader()) ????
{
     Product p = new Product();
     p.Name = reader.Field<string>("Name");
     p.Sku =  reader.Field<string>("Sku");  
     // etc.
     products.Add(p);
}

Answer 3

在像这样的情况下，像Dapper这样的简单ORM非常宝贵。让我们假设你的类Product是这样的，它反映了db

上的数据表

public class Product
{
    public string Name {get;set;}
    public string Sku {get; set;}
    public decimal Price {get; set;}
    ... and so on for the other fields ....
}

现在使用Dapper获取List<Product>，只需编写

即可

public List<Product> SelectAllProducts()
{
    using (IDbConnection connection = new SqlConnection(LOCAL))
    {
        string query = @"SELECT * FROM PRODUCTS ORDER BY Name";
        return connection.Query<Product>(query, null).ToList();
    }
}

需要将查询结果放入List <product> </product>中

3 个答案: