Question

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。

技术-堆栈

实体框架数据库首先
WPF
MVVM

问题说明

Add或Delete操作不会自动更新我的datagrid自动更新。

我在论坛上阅读了很多内容，但无所事事。

代码

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

<DataGrid DockPanel.Dock="Right" 
 AutoGenerateColumns="False"
 Name="ArtDatagrid" 
 ItemsSource="{Binding Article}" 
 SelectedItem="{Binding SelectedArticle}"
 CanUserAddRows="True"> 
            <DataGrid.Columns>
                <DataGridTextColumn 
                     Header="Id" 
                     Binding="{Binding id_article}"
                     Width="*"/>
                <DataGridTextColumn
                     Header="Nom"
                     Binding="{Binding nom}" 
                     Width="*"/>
                <DataGridTextColumn 
                     Header="Nom de la categorie" 
                     Binding="{Binding nom_categorie}"
                     Width="*"/>
                <DataGridTextColumn 
                     Header="QT"
                     Binding="{Binding quantite}"
                     Width="*"/>
                <DataGridTextColumn 
                     Header="Prix d'achat" 
                     Binding="{Binding prix_achat}"
                     Width="*"/>
                <DataGridTextColumn 
                     Header="prix de vente" 
                     Binding="{Binding prix_vente}"
                     Width="*"/>
            </DataGrid.Columns>
        </DataGrid>
</DockPanel>

Answer 1

因为您将新创建的文章添加到数据库中，而不是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);
}

添加一些记录时刷新我的数据网格（WPF mvvm和ef）

1 个答案: