<DataGrid x:Name="datagrid" ItemsSource="{Binding ElementName=Mwindow, Path=Preson}" Margin="0,0,0,20">



            <DataGrid.Columns>



            <DataGridTextColumn Binding="{Binding Name}" Header="Name"></DataGridTextColumn>



            <DataGridTextColumn Binding="{Binding Address}" Header="Address"></DataGridTextColumn>



            <DataGridTextColumn Binding="{Binding Age}" Header="Age"></DataGridTextColumn>



            </DataGrid.Columns>



        </DataGrid>

DataGridTextColumn  一定要在  <DataGrid.Columns>里

WPF 在使用 ItemsSource 之前，项集合必须为空