Convert DataTable to Listlt; Tgt; Implementation ideas and sample code
- 2020-05-24 06:03:12
- OfStack
A few days ago, I encountered a problem in my work: I needed to convert the DataTable data source that was queried into List < T > Is a generic collection of known T types. Reaction 1, I'm sure you need to use generics (isn't that bullshit? I said I'm going to convert to List < T > Generics are set), and you need to use "reflection" related. Ha ha. Soon, I made a small example, the test passed. Let me post the code and share it with you. The code has detailed comments, readers can clearly understand my ideas.
First, this is a generic transformation class that I wrote to do this. It is also the core part of implementing this function:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Collections;
using System.Reflection;
namespace DatableToList
{
class ConvertHelper<T> where T : new()
{
/// <summary>
/// Use reflection and generics
/// </summary>
/// <param name="dt"></param>
/// <returns></returns>
public static List<T> ConvertToList(DataTable dt)
{
// Define a collection
List<T> ts = new List<T>();
// Gets the type of this model
Type type = typeof(T);
// define 1 Three temporary variables
string tempName = string.Empty;
// traverse DataTable All the data rows in
foreach (DataRow dr in dt.Rows)
{
T t = new T();
// Get the common properties for this model
PropertyInfo[] propertys = t.GetType().GetProperties();
// Traverse all the properties of the object
foreach (PropertyInfo pi in propertys)
{
tempName = pi.Name;// Assign the property name to a temporary variable
// check DataTable Contains this column (column name == Object property name)
if (dt.Columns.Contains(tempName))
{
// Determine if this property is present Setter
if (!pi.CanWrite) continue;// This property is not writable
// The values
object value = dr[tempName];
// If not empty, the property assigned to the object
if (value != DBNull.Value)
pi.SetValue(t, value, null);
}
}
// Object is added to a generic collection
ts.Add(t);
}
return ts;
}
}
}
Below, is the instance called in the Main method:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Collections;
using System.Reflection;
namespace DatableToList
{
class Program
{
static void Main(string[] args)
{
DataTable dt = CreateDt();// To obtain 1 a DataTable
// By object type and DataTable , get the generic collection
List<Person> list = ConvertHelper<Person>.ConvertToList(dt);
// Walk through the generic collection and print the output.
foreach (var item in list)
{
Console.WriteLine(item.ToString());
}
Console.ReadKey();
}
/// <summary>
/// create 1 a DataTable And add data to provide tests.
/// </summary>
/// <returns></returns>
public static DataTable CreateDt()
{
DataTable dt = new DataTable();
dt.Columns.Add(new DataColumn("id", typeof(System.Int32)));
dt.Columns.Add(new DataColumn("name", typeof(System.String)));
dt.Columns.Add(new DataColumn("address", typeof(System.String)));
dt.Rows.Add(1,"Dylan","SZ");
dt.Rows.Add(2, "Jay", "TW");
dt.Rows.Add(3, "CQ", "HK");
return dt;
}
}
}
At the bottom, is the custom 1 simple class code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace DatableToList
{
class Person
{
private int id;
public int Id
{
get { return id; }
set { id = value; }
}
private string name;
public string Name
{
get { return name; }
set { name = value; }
}
private string address;
public string Address
{
get { return address; }
set { address = value; }
}
public override string ToString()
{
return "Person: " + id + " ," + name+","+address;
}
}
}
The above example passed the test, the level is limited, the deficiency, please forgive me.