使用 MVVM 在 TreeView 中显示实体 [英] Displaying Entities in TreeView using MVVM

问题描述

我正在按照 MVVM 模式制作 WPF 应用程序.在这个我使用实体框架，

I am making a WPF application following MVVM pattern. In this i am using entity framework,

我的实体结构很简单，它有3个实体:部门、课程、书籍，

my entity structure is simple, it has 3 entities: department, course, books,

一个系可以有很多课程，一个课程可以有很多书，

a department can have many courses, and a course can have many books,

现在我想在树视图中显示这个，所以我在 wpf 中的输出应该是这样的，

now i want to show this in a treeview, so my output in wpf should look like this,

Department1

  Course1

    Book1

    Book2

  Course2

    Book3

Department2

  Course

     Book

Department3   

在我的 ViewModel 中，我有 EntityContext 对象.但我不知道如何在树视图中显示它.我怎么能做到这一点.

in my ViewModel i have EntityContext object. But i dont know how to show this in a treeview. how i can do this.

推荐答案

我准备了一个小样本来复制这个..

I prepared the small sample to replicate this..

<Window x:Class="TestApp.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:this="clr-namespace:TestApp"
        Title="MainWindow" Height="350" Width="525">

    <Window.DataContext>
        <this:TreeViewModel />
    </Window.DataContext>

    <Window.Resources>

        <HierarchicalDataTemplate ItemsSource="{Binding Courses}" DataType="{x:Type this:Department}">
            <Label Content="{Binding DepartmentName}"/>
        </HierarchicalDataTemplate>

        <HierarchicalDataTemplate ItemsSource="{Binding Books}" DataType="{x:Type this:Course}">
            <Label Content="{Binding CourseName}"/>
        </HierarchicalDataTemplate>

        <DataTemplate DataType="{x:Type this:Book}">
            <Label Content="{Binding BookName}"/>
        </DataTemplate>

    </Window.Resources>

    <Grid>
        <TreeView ItemsSource="{Binding Departments}">

        </TreeView>
    </Grid>
</Window>

Model 和 ViewModel 类.

Model and ViewModel classes.

public class Book :ViewModelBase
    {
        private string bookname = string.Empty;

        public string BookName
        {
            get
            {
                return bookname;
            }
            set
            {
                bookname = value;
                OnPropertyChanged("BookName");
            }
        }

        public Book(string bookname)
        {
            BookName = bookname;
        }
    }

系类

public class Department : ViewModelBase
    {
        private List<Course> courses;

        public Department(string depname)
        {
            DepartmentName = depname;
            Courses = new List<Course>()
            {
                new Course("Course1"),
                new Course("Course2")
            };
        }

        public List<Course> Courses
        {
            get
            {
                return courses;
            }
            set
            {
                courses = value;
                OnPropertyChanged("Courses");
            }
        }

        public string DepartmentName
        {
            get;
            set;
        }
    }

课程班

public class Course :ViewModelBase
    {
        private List<Book> books;

        public Course(string coursename)
        {
            CourseName = coursename;
            Books = new List<Book>()
            {
                new Book("JJJJ"),
                new Book("KKKK"),
                new Book("OOOOO")
            };
        }

        public List<Book> Books
        {
            get
            {
                return books;
            }
            set
            {
                books = value;
                OnPropertyChanged("Books");
            }
        }

        public string CourseName
        {
            get;
            set;
        }
    }

TreeViewModel 类.

TreeViewModel class.

public class TreeViewModel :ViewModelBase
    {
        private List<Department> departments;

        public TreeViewModel()
        {
            Departments = new List<Department>()
            {
                new Department("Department1"),
                new Department("Department2")
            };
        }

        public List<Department> Departments
        {
            get
            {
                return departments;
            }
            set
            {
                departments = value;
                OnPropertyChanged("Departments");
            }
        }
    }

ViewModelBase 类.

ViewModelBase class.

public class ViewModelBase :INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        public void OnPropertyChanged(string propname)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propname));
            }
        }
    }

最后它以分层格式显示数据......我希望这会让你满意......

Finally it displays the data in the hierarchical format.. I hope this would satisfy you...

这篇关于使用 MVVM 在 TreeView 中显示实体的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！