I am getting the values in my observable Collection in ViewModel Class but not getting the values displayed in my ComboBox please help I referrred this link https://www.c-sharpcorner.com/article/explain-combo-box-binding-in-mvvm-wpf/
(我在ViewModel类的可观察集合中获取值，但未在ComboBox中显示值，请帮助我引用了此链接https://www.c-sharpcorner.com/article/explain-combo-box-binding-in -mvvm-wpf /)
XAML
(XAML)
<Window x:Class="MVVMDemo.UserRegistrationView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:viewmodel="clr-namespace:MVVMDemo"
Title="Window1" Height="300" Width="300">
<Window.Resources>
<viewmodel:ViewModel x:Key="ViewModel"/>
<viewmodel:DatetimeToDateConverter x:Key="MyConverter"/>
</Window.Resources>
<Grid DataContext="{Binding Source={StaticResource ViewModel}}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Text="Name" HorizontalAlignment="Center"/>
<TextBox Grid.Row="0" Grid.Column="1" Width="100" HorizontalAlignment="Center" Text="{Binding Student.Name, Mode=TwoWay}" Margin="76,0"/>
<TextBlock Grid.Row="1" Grid.Column="0" Text="Age" HorizontalAlignment="Center"/>
<TextBox Grid.Row="1" Grid.Column="1" Width="100" HorizontalAlignment="Center" Text="{Binding Student.Age, Mode=TwoWay}"/>
<Button Content="Submit" Command="{Binding SubmitCommand}" HorizontalAlignment="Right" Grid.Row="4" Grid.Column="0" RenderTransformOrigin="0.61,1.96" Margin="0,27.348,0,159.452"/>
<ComboBox Grid.Column="1" ItemsSource="{Binding Path=FillCourseId}" Name="cmb_CourseIDName" HorizontalAlignment="Left" Margin="76,5,0,0"
Grid.Row="3" VerticalAlignment="Top" Width="120" Grid.RowSpan="2">
<ComboBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Path=CourseName}"/>
<TextBlock Text=" - "/>
<TextBlock Text="{Binding Path=CourseID}"/>
</StackPanel>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
<ListView ItemsSource="{Binding Students}" Grid.Row="4" Grid.Column="1" Width="200"
Margin="27.657,34.948,24.342,159.452">
<ListView.View >
<GridView >
<GridViewColumn Header="Name" DisplayMemberBinding="{Binding Name}" Width="60"/>
<GridViewColumn Header="Age" DisplayMemberBinding="{Binding Age}" Width="60"/>
<GridViewColumn Header="Joining Date" DisplayMemberBinding="{Binding JoiningDate, Converter={StaticResource MyConverter}}" Width="80" />
</GridView>
</ListView.View>
</ListView>
</Grid>
</Window>
ViewModel Class here iam getting my values in my observableCollection FillCourseId after referring the link i mentioned iam still not able to get the values.
(在引用我提到的链接后，我在ViewModel类中获取了我的值在我的observableCollection FillCourseId中，但仍然无法获取值。)
please help !!! (请帮忙 ！！！)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Input;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Data.SqlClient;
using System.Data;
namespace MVVMDemo
{
public class ViewModel : ViewModelBase, INotifyPropertyChanged
{
private Student _student;
private ObservableCollection<Student> _students;
private ICommand _SubmitCommand;
private ObservableCollection<Student> _fillCourseId = new ObservableCollection<Student>();
static String connectionString = @"Data Source=Ramco-PCSQLEXPRESS;Initial Catalog=SIT_Ramco_DB;Integrated Security=True;";
SqlConnection con;
SqlCommand cmd;
// SqlDataAdapter adapter;
// DataSet ds;
//SqlDataReader reader;
public ObservableCollection<Student> FillCourseId
{
get { return _fillCourseId; }
set
{
_fillCourseId = value;
OnPropertyChanged("SystemStatusData");
}
}
public Student Student
{
get
{
return _student;
}
set
{
_student = value;
NotifyPropertyChanged("Student");
}
}
public ObservableCollection<Student> Students
{
get
{
return _students;
}
set
{
_students = value;
NotifyPropertyChanged("Students");
}
}
public ICommand SubmitCommand
{
get
{
if (_SubmitCommand == null)
{
_SubmitCommand = new RelayCommand(param => this.Submit(),
null);
}
return _SubmitCommand;
}
}
public void GetCourseIdFromDB()
{
try
{
con = new SqlConnection(connectionString);
con.Open();
cmd = new SqlCommand("select * from dev_Course", con);
SqlDataAdapter adapter = new SqlDataAdapter(cmd);
DataTable dt = new DataTable();
adapter.Fill(dt);
// Student Student = new Student();
for (int i = 0; i < dt.Rows.Count; ++i)
FillCourseId.Add(new Student
{
CourseID = dt.Rows[i][0].ToString(),
CourseName =dt.Rows[i][1].ToString()
});
}
catch (Exception ex)
{
}
}
public ViewModel()
{
Student = new Student();
Students = new ObservableCollection<Student>();
Students.CollectionChanged += new System.Collections.Specialized.NotifyCollectionChangedEventHandler(Students_CollectionChanged);
}
void Students_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
{
NotifyPropertyChanged("Students");
}
private void Submit()
{
Student.JoiningDate = DateTime.Today.Date;
Students.Add(Student);
Student = new Student();
}
// Property Changed Event
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyname)
{
var handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(propertyname));
}
}
}
ModelClass i have defined my properties here
(我在这里定义了我的属性的ModelClass)
namespace MVVMDemo
{
public class Student
{
public string Name { get; set; }
public int Age { get; set; }
public string Course { get; set; }
public string CourseName { get; set; }
public string CourseID { get; set; }
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