添加一些记录时刷新我的数据网格（WPF mvvm和ef）(Refresh my datagrid when add some records(WPF mvvm and ef))

简介我是WPF和mvvm的新手，因此我尝试通过应用库存管理来掌握基础知识。

达意堆栈

实体框架数据库首先 WPF MVVM

问题描述

Add或Delete操作不会自动更新我的datagrid不会自动更新。

我在论坛上阅读了很多东西，但无所事事。

码

ArticleViewModel

Class ArticleViewModel { private GStockEntities context; public ArticleViewModel() { context = new GStockEntities(); } public ObservableCollection<article> GetAllArticle() { ObservableCollection<article> Article = new ObservableCollection<article>(); try { var query = (from a in context.articles select a).ToList(); foreach (var item in query) { Article.Add(item); } } catch (Exception) { throw; } return Article; } public ObservableCollection<article> Article { get { return this.GetAllArticle(); } set { Set(ref _Article, value); } } private void Add() { article Article = new article(); Article.id_article = id; Article.nom = nom_Article; Article.id_categorie = GetIdCategoriByName(nom_categorie); Article.quantite = (int)qt; Article.prix_achat = (decimal)prix_achat; Article.prix_vente = (decimal)prix_vente; context.articles.Add(Article); context.SaveChanges(); } }

ViewModelBase

class ViewModelBase : INotifyPropertyChanged, INotifyDataErrorInfo { public ViewModelBase() { } #region INotifyPropertyChanged public event PropertyChangedEventHandler PropertyChanged; public void Notify([CallerMemberName]string propertyName = null) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } protected bool Set<TProperty>(ref TProperty attrib, TProperty value, [CallerMemberName]string propertyName = null) { if (!object.Equals(attrib, value)) { OnPropertyChanging(propertyName, attrib, value); attrib = value; Notify(propertyName); OnPropertyChanged(propertyName); return true; } return false; } protected virtual void OnPropertyChanged(string propertyName) { } protected virtual void OnPropertyChanging(string propertyName, object oldValue, object newValue) { } #endregion

}

ArticleView

Introduction I am new in WPF and mvvm and therefore I try to master the basics by making a application of inventory management.

Tech-Stack

Entity Framework database first WPF MVVM

Problem Description

An Add or Deleteoperation doesn't automatically updates my datagriddoesn't automatically updated.

I read lots of stuff on forums but nothing to do.

Code

ArticleViewModel

Class ArticleViewModel { private GStockEntities context; public ArticleViewModel() { context = new GStockEntities(); } public ObservableCollection<article> GetAllArticle() { ObservableCollection<article> Article = new ObservableCollection<article>(); try { var query = (from a in context.articles select a).ToList(); foreach (var item in query) { Article.Add(item); } } catch (Exception) { throw; } return Article; } public ObservableCollection<article> Article { get { return this.GetAllArticle(); } set { Set(ref _Article, value); } } private void Add() { article Article = new article(); Article.id_article = id; Article.nom = nom_Article; Article.id_categorie = GetIdCategoriByName(nom_categorie); Article.quantite = (int)qt; Article.prix_achat = (decimal)prix_achat; Article.prix_vente = (decimal)prix_vente; context.articles.Add(Article); context.SaveChanges(); } }

ViewModelBase

class ViewModelBase : INotifyPropertyChanged, INotifyDataErrorInfo { public ViewModelBase() { } #region INotifyPropertyChanged public event PropertyChangedEventHandler PropertyChanged; public void Notify([CallerMemberName]string propertyName = null) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } protected bool Set<TProperty>(ref TProperty attrib, TProperty value, [CallerMemberName]string propertyName = null) { if (!object.Equals(attrib, value)) { OnPropertyChanging(propertyName, attrib, value); attrib = value; Notify(propertyName); OnPropertyChanged(propertyName); return true; } return false; } protected virtual void OnPropertyChanged(string propertyName) { } protected virtual void OnPropertyChanging(string propertyName, object oldValue, object newValue) { } #endregion

}

ArticleView

最满意答案

因为您将新创建的文章添加到数据库，但不添加到绑定到网格的ObservableCollection 。一种解决方案可能是不直接在getter中从数据库返回文章。相反，您可以使用局部变量来存储它们：

private ObservableCollection<article> _article public ObservableCollection<article> Article { get { if (_article == null) _article = this.GetAllArticle(); return _article; } }

然后，您可以在add方法中使用该集合：

private void Add() { article Article = new article(); Article.id_article = id; Article.nom = nom_Article; Article.id_categorie = GetIdCategoriByName(nom_categorie); Article.quantite = (int)qt; Article.prix_achat = (decimal)prix_achat; Article.prix_vente = (decimal)prix_vente; context.articles.Add(Article); context.SaveChanges(); _article.Add(Article); }

Because you add the new created article to the database but not to the ObservableCollection that is bound to the grid. One solution could be not to return the articles from the database directly in the getter. Instead you could use a local variable to store them:

private ObservableCollection<article> _article public ObservableCollection<article> Article { get { if (_article == null) _article = this.GetAllArticle(); return _article; } }

Then you can use that collection in the add method:

private void Add() { article Article = new article(); Article.id_article = id; Article.nom = nom_Article; Article.id_categorie = GetIdCategoriByName(nom_categorie); Article.quantite = (int)qt; Article.prix_achat = (decimal)prix_achat; Article.prix_vente = (decimal)prix_vente; context.articles.Add(Article); context.SaveChanges(); _article.Add(Article); }

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