从数据表数据 C# 创建对象

Question

I am creating a Web service that takes to input parameters and returns data in objects. I have created a class Sending which has many properties.

I am retrieving the data from a database and loading them into a datatable. I am using datatables because i there can be many rows and i need to create an object of the sending class for each row.

I have also created get and set properties for each variable in the sending class.

Is there any way to insert the data from the datatable into the class objects?

Answer 1

If you have already created matching datamodel, then you can do something like this

IList<YourClass> items = yourdatatable.AsEnumerable().Select(x => 
    new YourClass
        {
            field1 = x.Field<int>("idcolumnName"),
            field2 = x.Field<string>("otherColumn")
        }).ToList();

Answer 2

Try this sample Extension. improve it with your requirement.

public static IEnumerable<T> ToIEnumerable<T>(this DataTable dt)
{
    List<T> list = Activator.CreateInstance<List<T>>();
    T instance = Activator.CreateInstance<T>();
    var prop = instance.GetType().GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.Instance);
    foreach (DataRow dr in dt.Rows)
    {
        T ins = Activator.CreateInstance<T>();
        foreach (var p in prop)
        {
            try
            {
                p.SetValue(ins, dr[p.Name], null);
            }
            catch { }
        }
        list.Add(ins);
    }
    return list;
}

usage:

yourDataTable.ToIEnumerable<YourClassModel>();

Answer 3

Don't try to do this by hand. ORMs do exactly this job in a much easier way. You can actually use a Micro-ORM like Dapper.NET or Massive to load data from the database as objects with a minimum of configuration.

For example, this query Dapper.NET query will load all Dog objects with the specified age:

public class Dog
{
    public int? Age { get; set; }
    ...
}            

var dogs = connection.Query<Dog>("select Age = @Age", new { Age = 5 });