C#•6mo ago

WPF DataGrid Not Updating

Hello i have a datagrid and a button on a window. I want to increase a value on datagrid by pressing that button. Value increases on code i can see that with debug but there is no changes on ui.

I am binding source like this on datagrid
ItemsSource="{Binding InventoryItems}"

I am binding source like this on datagrid
ItemsSource="{Binding InventoryItems}"

// This is my viewmodel

class InventoryItemVM : Base
{
    private ObservableCollection<InventoryItem> itemList = [];

    public ObservableCollection<InventoryItem> InventoryItems
    {
        get { return itemList; }
        set { itemList = value; OnPropertyChanged(); }
    }

    private InventoryItem? selectedItem = null;

    public InventoryItem? SelectedItem
    {
        get { return selectedItem; }
        set { selectedItem = value; }
    }

    public void AddStock(int id, int quantity)
    {
        InventoryItem? item = InventoryItems.FirstOrDefault(i => i.ID == id);
        if (item != null)
        {
            item.Quantity += quantity;
            OnPropertyChanged(nameof(InventoryItems));
        }
    }

    public InventoryItemVM()
    {
        InventoryItems =
        [
            new() { ID = 1, Name = "Item 1", Description = "Bla bla", Quantity = 10 },
            new() { ID = 2, Name = "Item 2", Description = "Bla bla", Quantity = 5 },
            new() { ID = 3, Name = "Item 3", Description = "Bla bla", Quantity = 3 }
        ];
    }
}

// This is my viewmodel

class InventoryItemVM : Base
{
    private ObservableCollection<InventoryItem> itemList = [];

    public ObservableCollection<InventoryItem> InventoryItems
    {
        get { return itemList; }
        set { itemList = value; OnPropertyChanged(); }
    }

    private InventoryItem? selectedItem = null;

    public InventoryItem? SelectedItem
    {
        get { return selectedItem; }
        set { selectedItem = value; }
    }

    public void AddStock(int id, int quantity)
    {
        InventoryItem? item = InventoryItems.FirstOrDefault(i => i.ID == id);
        if (item != null)
        {
            item.Quantity += quantity;
            OnPropertyChanged(nameof(InventoryItems));
        }
    }

    public InventoryItemVM()
    {
        InventoryItems =
        [
            new() { ID = 1, Name = "Item 1", Description = "Bla bla", Quantity = 10 },
            new() { ID = 2, Name = "Item 2", Description = "Bla bla", Quantity = 5 },
            new() { ID = 3, Name = "Item 3", Description = "Bla bla", Quantity = 3 }
        ];
    }
}

// And this is my code
InventoryItemVM inventoryDC = new();
public MainWindow()
{
    InitializeComponent();
    this.DataContext = inventoryDC;
}

private void IncreaseButton_Click(object sender, RoutedEventArgs e)
{
    if (inventoryDC.SelectedItem == null)
    {
        ShowErrorMessage("Please select an item to remove.");
        return;
    }

    inventoryDC.AddStock(inventoryDC.SelectedItem.ID, 1);
}

// And this is my code
InventoryItemVM inventoryDC = new();
public MainWindow()
{
    InitializeComponent();
    this.DataContext = inventoryDC;
}

private void IncreaseButton_Click(object sender, RoutedEventArgs e)
{
    if (inventoryDC.SelectedItem == null)
    {
        ShowErrorMessage("Please select an item to remove.");
        return;
    }

    inventoryDC.AddStock(inventoryDC.SelectedItem.ID, 1);
}

2 Replies

devaness•5mo ago

ObervableCollection only notifies the UI about adding and removing items, not about changing properties on items already inside the collection. You usually do not need to call PropertyChanged on an ObservableCollection yourself. Either implement INotifyPropertyChanged also for the InventoryItem class or (if you cannot or don't want to change your model class) create another viewmodel class for a single inventory item.

quantumOP•5mo ago

Thank you for your help

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WPF DataGrid Not Updating