c# - DataGridComboBoxColumn 不同行的不同 ItemsSource

Question

Here问了与我的问题类似的问题，但我没有在那里找到解决方案。

我的问题:如何将不同的数据(比如列表)绑定(bind)到不同行中每个 ComboBox 的“DataGridComboBoxColumn”。这是我试过的代码

XAML:

<Grid>
    <DataGrid x:Name="dg_TimeTable" AutoGenerateColumns="False" Margin="0,0,0,97" ColumnWidth="*">
        <DataGrid.Columns>
            <DataGridTextColumn IsReadOnly="True" Binding="{Binding CLASS}" Header="CLASS" />

            <DataGridComboBoxColumn Header="PERIOD" x:Name="gPeriods" SelectedValueBinding="{Binding PERIOD, Mode=TwoWay}" DisplayMemberPath="{Binding PERIOD}" />

            <DataGridComboBoxColumn Header="TEACHERS" x:Name="gTeachers" SelectedValueBinding="{Binding TEACHER, Mode=TwoWay}" DisplayMemberPath="{Binding TEACHER}" />

            <DataGridComboBoxColumn Header="SUBJECTS" x:Name="gSubjects" SelectedValueBinding="{Binding SUBJECT, Mode=TwoWay}" DisplayMemberPath="{Binding SUBJECT}"/>
        </DataGrid.Columns>
    </DataGrid>
</Grid>

.cs

using System.Collections.ObjectModel; // For ObservableCollection

public partial class MainWindow : Window
{
    ObservableCollection<string> listTeachersSix = null;
    ObservableCollection<string> listTeachersSeven = null;
    ObservableCollection<string> listTeachersEight = null;
    ObservableCollection<string> listTeachersNine = null;
    ObservableCollection<string> listTeachersTen = null;
    ObservableCollection<string> listSubjects = null;
    ObservableCollection<int> listPeriods = null;

    public MainWindow()
    {
        InitializeComponent();

        listTeachersSix = new ObservableCollection<string>();
        listTeachersSeven = new ObservableCollection<string>();
        listTeachersEight = new ObservableCollection<string>();
        listTeachersNine = new ObservableCollection<string>();
        listTeachersTen = new ObservableCollection<string>();
        listSubjects = new ObservableCollection<string>();
        listPeriods = new ObservableCollection<int>();

        listTeachersSix.Add("Vijay");
        listTeachersSix.Add("Naveen");
        listTeachersSix.Add("Gopal");
        listTeachersSix.Add("Somesh");

        listTeachersSeven.Add("Raj");
        listTeachersSeven.Add("Rama Krishna");
        listTeachersSeven.Add("Rakesh");
        listTeachersSeven.Add("Ram Babu");

        listTeachersEight.Add("Murali");
        listTeachersEight.Add("Ritesh");
        listTeachersEight.Add("Nagesh");
        listTeachersEight.Add("Tarun");

        listTeachersNine.Add("Bhaskar");
        listTeachersNine.Add("Babji");
        listTeachersNine.Add("Bhanu");
        listTeachersNine.Add("Balaji");

        listTeachersTen.Add("Lal");
        listTeachersTen.Add("Mohan");
        listTeachersTen.Add("Raj Sekhar");
        listTeachersTen.Add("Sunil");

        for (int i = 0; i <= 8; i++)
            listPeriods.Add(i);

        listSubjects.Add("Maths");
        listSubjects.Add("Physics");
        listSubjects.Add("Social");
        listSubjects.Add("English");
        listSubjects.Add("Hindi");
        listSubjects.Add("Telugu");


        List<Info> listTimeTable = new List<Info>()
        {
            new Info () { CLASS="6", PERIOD=1, TEACHER="Vijay", SUBJECT="Maths" },
            new Info () { CLASS="7", PERIOD=5, TEACHER="Raj", SUBJECT="Physics" },
            new Info () { CLASS="8", PERIOD=7, TEACHER="Murali", SUBJECT="Social" },
            new Info () { CLASS="10", PERIOD=4, TEACHER="Mohan", SUBJECT="English" },
            new Info () { CLASS="6", PERIOD=8, TEACHER="Naveen", SUBJECT="Maths" },
            new Info () { CLASS="9", PERIOD=3, TEACHER="Bhaskar", SUBJECT="Hindi" },
            new Info () { CLASS="8", PERIOD=6, TEACHER="Ritesh", SUBJECT="English" },
            new Info () { CLASS="10", PERIOD=2, TEACHER="Lal", SUBJECT="Social" }
        };

        dg_TimeTable.ItemsSource = listTimeTable;

        gPeriods.ItemsSource = listPeriods;

        gSubjects.ItemsSource = listSubjects;

        gTeachers.ItemsSource = listTeachersSix;

    }
}

public class Info
{
    public string CLASS { get; set; }
    public int PERIOD { get; set; }
    public string SUBJECT { get; set; }
    public string TEACHER { get; set; }
}

当我运行这段代码时，输​​出如下。

正如你们在我的代码中看到的那样，不同的类(class)有不同的老师。当我点击说第 9 课时，

"listTeachersNine" 应该添加到 "gTeachers.ItemsSource"。但是如果我这样做了

gTeachers.ItemsSource = listTeachersNine;

所有其他行都有效。我怎样才能在不改变其他行的情况下做到这一点。请给我一些想法...提前致谢

更新:

即使我在下面的代码中尝试过

 private void dg_TimeTable_SelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        int num = (sender as DataGrid).SelectedIndex;
        try
        {


            if (num == 0)
            {
                //listTeachersSix.Clear();

                //listTeachersSix.Add("Vijay");
                //listTeachersSix.Add("Naveen");
                //listTeachersSix.Add("Gopal");
                //listTeachersSix.Add("Somesh");
                gTeachers.ItemsSource = listTeachersSix;

            }
            else if (num == 1)
            {
                //listTeachersSix.Clear();

                //listTeachersSix.Add("Raj");
                //listTeachersSix.Add("Rama Krishna");
                //listTeachersSix.Add("Rakesh");
                //listTeachersSix.Add("Ram Babu");
                gTeachers.ItemsSource = listTeachersSeven;
            }
            else if (num == 2)
            {
                //listTeachersSix.Clear();

                //listTeachersSix.Add("Murali");
                //listTeachersSix.Add("Ritesh");
                //listTeachersSix.Add("Nagesh");
                //listTeachersSix.Add("Tarun");
                gTeachers.ItemsSource = listTeachersEight;

            }
       }

我尝试了注释部分和未注释部分，但没有用。当我启动我的应用程序时，它显示如上图所示。但是当点击特定行时，所有其他行的数据都消失了。但问题是，它正在更新新的教师数据。请看下面两张图片。

因此，在不更改其他行的情况下，我可以更新我想要的行......

Answer 1

我可以想到几种方法来做到这一点。

如果您不关心严格的 MVVM 设计，您可以使用 IValueConverter，将您的 CLASS 传递给它，并让转换器找出要返回的列表。类似

的东西

public object Convert(object value, Type targetType,
    object parameter, CultureInfo culture)
{
    string key = value as string;
    switch (key)
    {
        case "1":
            return SomethingStatic.TeacherList1;
        case "2":
            return SomethingStatic.TeacherList2;
        ...
    }
}

如果你想让它动态化并避免在你的 Converter 中硬编码列表引用，你可以使用 IMultiValueConverter 并将变量数组作为另一个绑定(bind)值传递给它，并调整代码以简单地找到正确的从其他绑定(bind)值传入的数组中的 ItemsSource。

请注意，要使用其中任何一个，您可能必须从 DataGridComboBoxColumn 切换到 DataGridTemplateColumn，因为绑定(bind)无法从 ComboBoxColumn.

<DataGridTemplateColumn Header="TEACHERS">
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <ComboBox ItemsSource="{Binding CLASS, Converter={StaticResource TestConverter}}" 
                      SelectedItem="{Binding TEACHER}" />
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>
</DataGridTemplateColumn>

另一种替代解决方案是将 ValidTeachers 列表添加到每个 DataRow 的项目中，在您的例子中是 Info 对象。

public class Info
{
    public string CLASS { get; set; }
    public int PERIOD { get; set; }
    public string SUBJECT { get; set; }
    public string TEACHER { get; set; }
    public List<string> ValidTeachers { get; set; }
}

您还需要一个 Change Event，这样每当 CLASS 发生变化时，ValidTeachers 数组就会更新。

我敢肯定还有其他选项可能更简洁，但如果您正在寻找简单易用的东西，我会推荐其中之一。