Convert DataTable to List

Question

I have an strongly typed DataTable of type MyType, I\'d like convert it in a List.

How can I do this ?

Thanks.

Answer 1

thanks for all of posts.... I have done it with using Linq Query, to view this please visit the following link

http://codenicely.blogspot.com/2012/02/converting-your-datatable-into-list.html

Answer 2

Try this code and This is easiest way to convert datatable to list

List<DataRow> listtablename = dataTablename.AsEnumerable().ToList();

Answer 3

List<MyType> listName = dataTableName.AsEnumerable().Select(m => new MyType()
{
   ID = m.Field<string>("ID"),
   Description = m.Field<string>("Description"),
   Balance = m.Field<double>("Balance"),
}).ToList()

Answer 4

That pretty works!!

I made some updates from @suneelsarraf's answer and I removed Convert.ChangeType() because it keeps throwing Invalid Cast Exception. Have a take a look!

#region *** Convert DT to List<Object> ***

    private List<I> ConvertTo<I>(DataTable datatable) where I : class
    {
        List<I> lstRecord = new List<I>();
        try
        {
            List<string> columnsNames = new List<string>();
            foreach (DataColumn DataColumn in datatable.Columns)
                columnsNames.Add(DataColumn.ColumnName);
            lstRecord = datatable.AsEnumerable().ToList().ConvertAll<I>(row => GetObject<I>(row, columnsNames));
            return lstRecord;
        }
        catch
        {
            return lstRecord;
        }

    }

    private I GetObject<I>(DataRow row, List<string> columnsName) where I : class
    {
        I obj = (I)Activator.CreateInstance(typeof(I));
        try
        {
            PropertyInfo[] Properties = typeof(I).GetProperties();
            foreach (PropertyInfo objProperty in Properties)
            {
                string columnname = columnsName.Find(name => name.ToLower() == objProperty.Name.ToLower());
                if (!string.IsNullOrEmpty(columnname))
                {
                    object dbValue = row[columnname];
                    if (dbValue != DBNull.Value)
                    {
                        if (Nullable.GetUnderlyingType(objProperty.PropertyType) != null)
                        {
                            objProperty.SetValue(obj, Convert.ChangeType(dbValue, Type.GetType(Nullable.GetUnderlyingType(objProperty.PropertyType).ToString())), null);
                        }
                        else
                        {
                            objProperty.SetValue(obj, Convert.ChangeType(dbValue, Type.GetType(objProperty.PropertyType.ToString())), null);
                        }
                    }
                }
            }
            return obj;
        }
        catch(Exception ex)
        {
            return obj;
        }
    }

    #endregion

And this is how you use in your code.

// Other Codes Here
var lstResult = ConvertTo<TEntity>(dataTableName); // Convert DT to List<TEntity>

Have Fun! Be Safe in 2020.

Answer 5

Data table to List

    #region "getobject filled object with property reconized"

    public List<T> ConvertTo<T>(DataTable datatable) where T : new()
    {
        List<T> Temp = new List<T>();
        try
        {
            List<string> columnsNames = new List<string>();
            foreach (DataColumn DataColumn in datatable.Columns)
                columnsNames.Add(DataColumn.ColumnName);
            Temp = datatable.AsEnumerable().ToList().ConvertAll<T>(row => getObject<T>(row, columnsNames));
            return Temp;
        }
        catch
        {
            return Temp;
        }

    }
    public T getObject<T>(DataRow row, List<string> columnsName) where T : new()
    {
        T obj = new T();
        try
        {
            string columnname = "";
            string value = "";
            PropertyInfo[] Properties;
            Properties = typeof(T).GetProperties();
            foreach (PropertyInfo objProperty in Properties)
            {
                columnname = columnsName.Find(name => name.ToLower() == objProperty.Name.ToLower());
                if (!string.IsNullOrEmpty(columnname))
                {
                    value = row[columnname].ToString();
                    if (!string.IsNullOrEmpty(value))
                    {
                        if (Nullable.GetUnderlyingType(objProperty.PropertyType) != null)
                        {
                            value = row[columnname].ToString().Replace("$", "").Replace(",", "");
                            objProperty.SetValue(obj, Convert.ChangeType(value, Type.GetType(Nullable.GetUnderlyingType(objProperty.PropertyType).ToString())), null);
                        }
                        else
                        {
                            value = row[columnname].ToString().Replace("%", "");
                            objProperty.SetValue(obj, Convert.ChangeType(value, Type.GetType(objProperty.PropertyType.ToString())), null);
                        }
                    }
                }
            }
            return obj;
        }
        catch
        {
            return obj;
        }
    }

    #endregion

IEnumerable collection To Datatable

    #region "New DataTable"
    public DataTable ToDataTable<T>(IEnumerable<T> collection)
    {
        DataTable newDataTable = new DataTable();
        Type impliedType = typeof(T);
        PropertyInfo[] _propInfo = impliedType.GetProperties();
        foreach (PropertyInfo pi in _propInfo)
            newDataTable.Columns.Add(pi.Name, pi.PropertyType);

        foreach (T item in collection)
        {
            DataRow newDataRow = newDataTable.NewRow();
            newDataRow.BeginEdit();
            foreach (PropertyInfo pi in _propInfo)
                newDataRow[pi.Name] = pi.GetValue(item, null);
            newDataRow.EndEdit();
            newDataTable.Rows.Add(newDataRow);
        }
        return newDataTable;
    }

Answer 6

There is a little example that you can use

            DataTable dt = GetCustomersDataTable(null);            

            IEnumerable<SelectListItem> lstCustomer = dt.AsEnumerable().Select(x => new SelectListItem()
            {
                Value = x.Field<string>("CustomerId"),
                Text = x.Field<string>("CustomerDescription")
            }).ToList();

            return lstCustomer;