方式一：通过DataGrid 数据源即DataTable，在DataTable里面动态增加了列之后，重新构造每一行数据，设置DataGrid.ItemsSource = null; 然后再重新设置ItemsSource到DataTable

 public partial class MainWindow : Window{public MainWindow(){InitializeComponent();}int newColumnIndex = 1;private void AddColum_Click(object sender, RoutedEventArgs e){DataTable dt = (DataGridtest.ItemsSource as DataView).ToTable();if (DataGridtest.ItemsSource == null){return;}dt.Columns.Add(new DataColumn("New Column" + newColumnIndex++));for (int i = 0; i < dt.Rows.Count; i++){dt.Rows[i][dt.Columns.Count - 1] = i.ToString() + " - New Column";}DataGridtest.ItemsSource = null;DataGridtest.ItemsSource = dt.DefaultView;}private void ShowClomun_Click(object sender, RoutedEventArgs e){DataTable dt = new DataTable();for (int i = 0; i < 100; i++){dt.Columns.Add(new DataColumn(string.Format("{0}{1}", "Colum", i)));}DataRow dr;for (int i = 0; i < 200; i++){dr = dt.NewRow();for (int columIndex = 0; columIndex < dt.Columns.Count; columIndex++)dr[columIndex] = i.ToString() + " - " + columIndex.ToString();dt.Rows.Add(dr);}DataGridtest.ItemsSource = dt.DefaultView;}
}

方式二：通过ObservableCollection<dynamic>集合，它可以动态的添加属性，这种类型添加好属性之后，重新设置DataGrid的ItemsSource绑定即可

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Data;
using System.Dynamic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;namespace DynymicDataGrid
{/// <summary>/// MainWindow.xaml 的交互逻辑/// </summary>public partial class MainWindow : Window{public MainWindow(){InitializeComponent();}List<string> header = new List<string>();ObservableCollection<dynamic> items = new ObservableCollection<dynamic>();public MainWindow(){InitializeComponent();for (int i = 0; i < 100; i++){header.Add("Colum" + i);}}int newColumnIndex = 1;private void AddColum_Click(object sender, RoutedEventArgs e){foreach (ExpandoObject item in items){dynamic x = item;x.NewColumn = "NewColumn";}DataGridtest.Columns.Add(new DataGridTextColumn() { Header = "NewColumn", Binding = new Binding("NewColumn") });newColumnIndex++;}private void ShowClomun_Click(object sender, RoutedEventArgs e){for (int i = 0; i < 100; i++){dynamic item = new ExpandoObject();foreach (var vheader in header){item.A1 = "A value - " + i.ToString();item.A2 = "A value - " + i.ToString();item.A3 = "A value - " + i.ToString();item.A4 = "A value - " + i.ToString();item.A5 = "A value - " + i.ToString();item.A6 = "A value - " + i.ToString();item.A7 = "A value - " + i.ToString();item.A8 = "A value - " + i.ToString();item.A9 = "A value - " + i.ToString();item.A10 = "A value - " + i.ToString();item.A10 = "A value - " + i.ToString();item.A12 = "A value - " + i.ToString();item.A13 = "A value - " + i.ToString();item.A14 = "A value - " + i.ToString();item.A15 = "A value - " + i.ToString();item.A16 = "A value - " + i.ToString();item.A17 = "A value - " + i.ToString();item.A18 = "A value - " + i.ToString();item.A19 = "A value - " + i.ToString();item.A20 = "A value - " + i.ToString();item.A21 = "A value - " + i.ToString();item.A22 = "A value - " + i.ToString();item.A23 = "A value - " + i.ToString();item.A24 = "A value - " + i.ToString();item.A25 = "A value - " + i.ToString();item.A26 = "A value - " + i.ToString();item.A27 = "A value - " + i.ToString();item.A28 = "A value - " + i.ToString();item.A29 = "A value - " + i.ToString();item.A30 = "A value - " + i.ToString();item.A31 = "A value - " + i.ToString();item.A32 = "A value - " + i.ToString();item.A33 = "A value - " + i.ToString();item.A34 = "A value - " + i.ToString();item.A35 = "A value - " + i.ToString();item.A36 = "A value - " + i.ToString();item.A37 = "A value - " + i.ToString();item.A38 = "A value - " + i.ToString();item.A39 = "A value - " + i.ToString();item.A40 = "A value - " + i.ToString();item.A41 = "A value - " + i.ToString();item.A42 = "A value - " + i.ToString();item.A43 = "A value - " + i.ToString();item.A44 = "A value - " + i.ToString();item.A45 = "A value - " + i.ToString();item.A46 = "A value - " + i.ToString();item.A47 = "l value - " + i.ToString();item.A48 = "A value - " + i.ToString();item.A49 = "A value - " + i.ToString();item.A50 = "A value - " + i.ToString();item.A51 = "A value - " + i.ToString();item.A52 = "A value - " + i.ToString();item.A53 = "A value - " + i.ToString();item.A54 = "A value - " + i.ToString();item.A55 = " A value - " + i.ToString();item.A56 = " A value - " + i.ToString();item.A57 = " A value - " + i.ToString();item.A58 = " A value - " + i.ToString();item.A59 = " A value - " + i.ToString();item.A60 = " A value - " + i.ToString();item.A61 = " A value - " + i.ToString();item.A62 = " A value - " + i.ToString();item.A63 = " A value - " + i.ToString();item.A64 = " A value - " + i.ToString();item.A65 = " A value - " + i.ToString();item.A66 = " A value - " + i.ToString();item.A67 = " A value - " + i.ToString();item.A68 = " A value - " + i.ToString();item.A69 = " A value - " + i.ToString();item.A70 = " A value - " + i.ToString();item.A71 = " A value - " + i.ToString();item.A72 = " A value - " + i.ToString();item.A73 = " A value - " + i.ToString();item.A74 = " A value - " + i.ToString();item.A75 = " A value - " + i.ToString();item.A76 = " A value - " + i.ToString();item.A77 = " A value - " + i.ToString();item.A78 = " A value - " + i.ToString();item.A79 = "A value - " + i.ToString();item.A80 = "A value - " + i.ToString();item.A81 = " A value - " + i.ToString();item.A82 = " A value - " + i.ToString();item.A83 = " A value - " + i.ToString();item.A84 = " A value - " + i.ToString();item.A85 = " A value - " + i.ToString();item.A86 = " A value - " + i.ToString();item.A87 = " A value - " + i.ToString();item.A88 = " A value - " + i.ToString();item.A89 = " A value - " + i.ToString();item.A90 = " A value - " + i.ToString();item.A91 = " A value - " + i.ToString();item.A92 = " A value - " + i.ToString();item.A93 = " A value - " + i.ToString();item.A94 = " A value - " + i.ToString();item.A95 = " A value - " + i.ToString();item.A96 = " A value - " + i.ToString();item.A97 = " A value - " + i.ToString();item.A98 = " A value - " + i.ToString();item.A99 = "A value - " + i.ToString();}items.Add(item);}for (int i = 0; i < 40; i++){DataGridtest.Columns.Add(new DataGridTextColumn() { Header = "A" + i, Binding = new Binding("A" + i) });}DataGridtest.ItemsSource = items;}}
}