小编D.J*_*omp的帖子

每次输入正确的char输入时都会执行默认语句.我错过了什么？

我的产出:

正确的产出:

#include <stdio.h>

void main() {
    char ch = '?'; 
    float f;
    double a = 10.00, b = 20.00;
    int i;
    for (i = 0; i < 10; i++) { 
        scanf("%c", &ch);

        switch (ch) {
          case '+': 
            f = a + b; 
            printf("f = %.0f\n", f);
            break;

          case '-': 
            f = a - b; 
            printf("f = %.0f\n", f);
            break;

          case '*': 
            f = a * b; 
            printf("f = %.0f\n", f);
            break;

          case '/': 
            f = a / b; …

我试图将ObservableCollection的T绑定到DataGrid的DataGridComboBoxColumn.
DataGrid定义是:

<DataGrid AutoGenerateColumns="False" ItemsSource="{Binding Model, IsAsync=True}">

     <DataGrid.Columns>
         <DataGridTextColumn  Header="Column Entry"  IsReadOnly="True" Binding="{Binding ColumnName}"/>
         <DataGridComboBoxColumn Header="Road Type" ItemsSource="{Binding RoadTypes}"/>
    </DataGrid.Columns>

</DataGrid>

这是ViewModel和Model

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        var viewModel = new ViewModel();
        DataContext = viewModel;
    }
}

public class ViewModel : ViewModelBase
{
    private ObservableCollection<Model> _model;

    public ViewModel()
    {
        var list = new List<Model>();
        var roadTypes = new ObservableCollection<RoadType>
                            {
                                new RoadType
                                    {
                                        Code = 1,
                                        Id = 1,
                                        Name = "Name1"
                                    },
                                new …