7 way to convert DataTable to generic List - C#

Conversion DataTable to Generic List<t>. We can do it in various way.

Solution 1:

DataTable dt = CreateDataTable();
List<datarow> list = new List<datarow>();
foreach (DataRow dr in dt.Rows)
{
     list.Add(dr);
}

Solution 2:

DataTable table = new DataTable {
Columns = {
{"Foo", typeof(int)},
{"Bar", typeof(string)}
}
};

for (int i = 0; i < 5000; i++) {
     table.Rows.Add(i, "Row " + i);
}

List<T> data = new List<t>(table.Rows.Count);
foreach (DataRow row in table.Rows) {
      data.Add(new T((int)row[0], (string)row[1]));
}

Solution 3:

Using Linq expression. It return data in List<t>.

List<string> list =dataTable.Rows.OfType<datarow>().Select(dr => dr.Field<string>(0)).ToList();

Solution 4:

Using Linq/lamda expression.

List<employee> list= new List<employee>();
list = (from DataRow row in dt.Rows

select new Employee
{
     FirstName = row["ColumnName"].ToString(),
     LastName = row["ColumnName"].ToString()
}).ToList();

Solution 5:

Using Linq expression.

List<t> target = dt.AsEnumerable()
.Select(row => new T
{
     // assuming column 0's type is Nullable<long>
     ID = row.Field<long?>(0).GetValueOrDefault()
     Name = String.IsNullOrEmpty(row.Field<string>(1))
     ? "not found"
     : row.Field<string>(1)
})
.ToList();

Solution 6:

Using Linq/lamda expression. All are return array of datarow in List<t>.

List<datarow> list1= dataTable.Select().ToList();
List<datarow> list2= dataTable.Rows.Cast<datarow>().ToList();
List<datarow> list3 = dataTable.AsEnumerable().ToList();
List<datarow> list4 = new List<datarow>(dataTable.select());

Here result will return all rows of datatable, as an array of datarows, and the List constructor accepts that array of objects as an argument to initially fill our List<datarow> with.

Solution 7:

Using reflection PropertyInfo class.(.Net4)

sealed class Tuple<T1, T2>
{

       public Tuple() {}
       public Tuple(T1 value1, T2 value2) {Value1 = value1; Value2 = value2;}
       public T1 Value1 {get;set;}
       public T2 Value2 {get;set;}
}



public static List<T> Convert<T>(DataTable table)

where T : class, new()
{
      List<Tuple<DataColumn, PropertyInfo>> map =
      new List<Tuple<DataColumn,PropertyInfo>>();
      foreach(PropertyInfo pi in typeof(T).GetProperties())
      {

         ColumnAttribute col = (ColumnAttribute)
         Attribute.GetCustomAttribute(pi, typeof(ColumnAttribute));
         if(col == null) continue;
         if(table.Columns.Contains(col.FieldName))
         {
             map.Add(new Tuple<DataColumn,PropertyInfo>(
             table.Columns[col.FieldName], pi));
         }
      }

      List<T> list = new List<T>(table.Rows.Count);
      foreach(DataRow row in table.Rows)
      {
          if(row == null)
          {
              list.Add(null);
              continue;
          }

          T item = new T();
          foreach(Tuple<DataColumn,PropertyInfo> pair in map) {
              object value = row[pair.Value1];
              if(value is DBNull) value = null;
              pair.Value2.SetValue(item, value, null);
          }

         list.Add(item);
   }

   return list; 

}

 


By Mohd Zulkamal
NOTE : – If You have Found this post Helpful, I will appreciate if you can Share it on Facebook, Twitter and Other Social Media Sites. Thanks =)