我有两门课
- 条款**
public class Terms
{
[PrimaryKey, AutoIncrement]
public int TermId { get; set; }
public string TermName { get; set; }
public string StartDate { get; set; }
public string EndDate { get; set; }
public DateTime RealStart => DateTime.Parse(StartDate);
public DateTime RealEnd => DateTime.Parse(EndDate);
}- 课程**
public class Courses
{
[PrimaryKey, AutoIncrement]
public int CourseId { get; set; }
public int TermId { get; set; }
public string CourseName { get; set; }
public string StartDate { get; set; }
public string EndDate { get; set; }
public DateTime RealStart => DateTime.Parse(StartDate);
public DateTime RealEnd => DateTime.Parse(EndDate);
public string CIName { get; set; }
public string CIEmail { get; set; }
public string CIPhone { get; set; }
public string Status { get; set; }
public bool Notifications { get; set; }
public string Notes { get; set; }
}第1学期-课程1课程2
在第1学期选择课程时，我尝试显示该课程的扩展课程详细信息。
- xaml**
<CollectionView x:Name="CourseCollection"
ItemsSource="{Binding Courses}"
EmptyView="No Courses to display"
SelectionMode="Single"
SelectionChanged="CourseCollection_SelectionChanged">- C#**
private async void CourseCollection_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
var course = (Courses)e.CurrentSelection.FirstOrDefault();
if (e.CurrentSelection != null)
{
await Navigation.PushAsync(new CoursesDetail(course));
}
}它显示了两条航线
- 课程详细信息**
- xaml**
<CollectionView x:Name="CoursesCollection"
ItemsSource="{Binding Courses}"
EmptyView="No courses to view"
SelectionMode="Single">
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout>
<Grid Padding="5" RowSpacing="1" ColumnSpacing="10">
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Label Grid.Row="0" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Course ID</Label>
<Label Text="{Binding CourseId}" Grid.Row="0" Grid.Column="1" FontSize="Medium" x:Name="CourseId" ></Label>
<Label Grid.Row="1" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Term ID</Label>
<Label Text="{Binding TermId}" Grid.Row="1" Grid.Column="1" FontSize="Medium" x:Name="TermId"></Label>
<Label Grid.Row="2" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Course Name</Label>
<Label x:Name="CourseName" Grid.Row="2" Grid.Column="1" FontSize="Medium" VerticalTextAlignment="Center" Text="{Binding CourseName}"></Label>
<Label Grid.Row="3" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Start Date</Label>
<Label Grid.Row="3" Grid.Column="1" FontSize="Medium" x:Name="StartDate" Text="{Binding StartDate}"></Label>
<Label Grid.Row="4" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">End Date</Label>
<Label Grid.Row="4" Grid.Column="1" FontSize="Medium" x:Name="EndDate" Text="{Binding EndDate}"></Label>
<Label Grid.Row="5" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Instructor Name</Label>
<Label x:Name="CIName" Grid.Row="5" Grid.Column="1" FontSize="Medium" VerticalTextAlignment="Center" Text="{Binding CIName}"></Label>
<Label Grid.Row="6" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Instructor Email</Label>
<Label x:Name="CIEmail" Grid.Row="6" Grid.Column="1" FontSize="Medium" VerticalTextAlignment="Center" Text="{Binding CIEmail}"></Label>
<Label Grid.Row="7" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Instructor Phone</Label>
<Label x:Name="CIPhone" Grid.Row="7" Grid.Column="1" FontSize="Medium" VerticalTextAlignment="Center" Text="{Binding CIPhone}"></Label>
<Label Grid.Row="8" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Course Status</Label>
<Label Grid.Row="8" Grid.Column="1" x:Name="Status" FontSize="Medium" Text="{Binding Status}"></Label>
<Label Grid.Row="9" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Notes</Label>
<Label x:Name="Notes" Grid.Row="9" Grid.Column="1" FontSize="Medium" Text="{Binding Notes}"></Label>
<Label Grid.Row="10" Grid.Column="0" FontSize="Medium" VerticalTextAlignment="Center">Notifications</Label>
<Label x:Name="Notifications" Grid.Row="10" Grid.Column="1" FontSize="Medium" Text="{Binding Notifications}"></Label>
</Grid>
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>- c#**
public partial class CoursesDetail : ContentPage
{
private readonly int _selectedCourseId;
private Courses theBiggestCourses;
protected override async void OnAppearing()
{
base.OnAppearing();
CoursesCollection.ItemsSource = await database.GetCourses(_selectedCourseId);
AssessmentsCollection.ItemsSource = await database.GetAssessments(_selectedCourseId);
}
public CoursesDetail()
{
InitializeComponent();
}
public CoursesDetail(Courses courses)
{
_selectedCourseId = courses.CourseId;
InitializeComponent();
this.theBiggestCourses = courses;
}我试过手动通过构造函数传递每个文本字段，我有一些应该自动填充的示例数据，并认为这是问题所在，但我删除了这些方法，并尝试手动添加一个术语，该术语的课程，但只要它超过1门课程，它就会崩溃。
编辑--我的豌豆大小的大脑理论可能是，由于Terms是作为一个对象传递的，捕获了该对象的所有元素，它仍然保留着该Term对象，所以当调用Courses对象时，它捕获了该terms对象的所有courses对象。我希望我解释得很好。
编辑2-获取课程
public static async Task<IEnumerable<Courses>> GetCourses(int termId)
{
await Init();
var courses = await db.Table<Courses>()
.Where(i => i.TermId == termId).ToListAsync();
return courses;
}
public static async Task<IEnumerable<Courses>> GetCourses()
{
await Init();
var courses = await db.Table<Courses>().ToListAsync();
return courses;
}这是GetCourses的两个参数，是因为我们在这里传递了一个int型的termId，在方法中传递了一个object，然后默认为非参数化的构造函数，它会返回所有的参数吗？
1条答案
按热度按时间r1zk6ea11#
GetCourses需要一个TermID但调用它时传递的是
CourseID