<Grid>  <Grid.RowDefinitions>   <RowDefinition Height="25"></RowDefinition>   <RowDefinition></RowDefinition>  </Grid.RowDefinitions>  <Button Height="23" Click="Button_Click" Content="Click" Grid.Row="0"></Button>  <DataGrid Name="dgStudent" AutoGenerateColumns="False" IsEnabled="True" Grid.Row="1"     EnableColumnVirtualization="True" EnableRowVirtualization="True">   <DataGrid.Columns>    <DataGridTextColumn Header="Name" Binding="{Binding Name}" Width="80"></DataGridTextColumn>    <DataGridTemplateColumn Header="Age" Width="70">     <DataGridTemplateColumn.CellTemplate>      <DataTemplate>       <TextBox Margin="5" Text="{Binding Age, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></TextBox>      </DataTemplate>     </DataGridTemplateColumn.CellTemplate>    </DataGridTemplateColumn>    <DataGridTemplateColumn Header="Course" Width="100">     <DataGridTemplateColumn.CellTemplate>      <DataTemplate>       <ComboBox Margin="5" ItemsSource="{Binding CourseSource}" Text="{Binding Course, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></ComboBox>      </DataTemplate>     </DataGridTemplateColumn.CellTemplate>    </DataGridTemplateColumn>   </DataGrid.Columns>  </DataGrid> </Grid>

 public class Student {  public string Name { get; set; }  public string Age { get; set; }  public List<string> CourseSource { get; set; } = new List<string>() { "C", "C++", "C#" };  public string Course { get; set; } } private void Button_Click(object sender, RoutedEventArgs e)  {   var students = new List<Student>();   for (int i = 1; i <= 50; i++)   {    var student = new Student()    {     Name = $"student{i}"    };    students.Add(student);   }   this.dgStudent.ItemsSource = null;   this.dgStudent.ItemsSource = students;  }