How can I get value from db and set cell of datagrid wpf

Question

When user enter the barcode of datagrid's first column database fetches required data (PRODUCT_NAME and PURCHASE_PRICE). I want to put it in the related cell data i have.

I can get the data what i want but i dont know how to set of selected item's PRODUCT_NAME and PURCHASE_PRICE cell.

XAML

<DataGrid x:Name="UrunGrid" Grid.Row="0" CanUserAddRows="True" AutoGenerateColumns="False" AlternatingRowBackground="#FF788697" AlternationCount = "2" HorizontalScrollBarVisibility="Hidden" CellEditEnding="UrunGrid_CellEditEnding" SelectionUnit="FullRow" CurrentCellChanged="UrunGrid_CurrentCellChanged" RowEditEnding="UrunGrid_RowEditEnding" SelectedCellsChanged="UrunGrid_SelectedCellsChanged" SelectionChanged="UrunGrid_SelectionChanged">
            <DataGrid.Columns>
                <DataGridTextColumn Header="Barkod" Binding="{Binding BARKOD}" Width="2*" />
                <DataGridTextColumn Header="Ürün Açıklaması" Binding="{Binding PRODUCT_NAME}" Width="4*"/>
                <DataGridTextColumn Header="Adet" Binding="{Binding QUANTITY}" Width="*"/>
                <DataGridTextColumn Header="ISK" Binding="{Binding DISCOUNT}" Width="*"/>
                <DataGridTextColumn Header="KDV" Binding="{Binding TAX}" Width="*"/>
                <DataGridTextColumn Header="Birim Fiyat" Binding="{Binding PURCHASE_PRICE}" Width="*"/>
                <DataGridTextColumn Header="Tutar" Binding="{Binding AMOUNT}" Width="*"/>
            </DataGrid.Columns>
        </DataGrid>

XAML.CS

private void UrunGrid_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)
    {  
        // Eğer seçili kolon barkod ise
        if ((string)e.Column.Header == "Barkod")
        {
            // Girilen değeri barkod değişkenine atıyor.
            TextBox t = e.EditingElement as TextBox;
            string girilenbarkod = t.Text.ToString();

            // Veritabanında kayıtlı mı kontrolü. Değer 0 ise kayıt yok.
            SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["calcuconnection"].ToString());
            String insertquery = "SELECT count(BARCODE) FROM PRODUCT WHERE BARCODE=@BARKOD";
            SqlCommand command = new SqlCommand(insertquery, connection);
            connection.Open();
            command.Parameters.AddWithValue("@BARKOD", girilenbarkod);
            int deger = (int)command.ExecuteScalar();
            connection.Close();

            if (deger == 0)
            {

            }
            else
            {
                string cekilenurunadi;
                string cekilenalisfiyati;

                int col = UrunGrid.CurrentCell.Column.DisplayIndex;
                int rows = UrunGrid.SelectedIndex;

                String insertquery2 = "SELECT PRODUCT_NAME, PURCHASE_PRICE FROM PRODUCT WHERE BARCODE=@BARKOD";
                SqlCommand command2 = new SqlCommand(insertquery2, connection);
                connection.Open();
                command2.Parameters.AddWithValue("@BARKOD", girilenbarkod);
                dataReader = command2.ExecuteReader();
                while (dataReader.Read())
                {
                    cekilenurunadi = dataReader["PRODUCT_NAME"].ToString();
                    cekilenalisfiyati = dataReader["PURCHASE_PRICE"].ToString(); 
                    MessageBox.Show(cekilenurunadi+cekilenalisfiyati);
                }


                connection.Close();

            }

        }
       
    }

CLASS

class Invoice
{
    public string BARKOD { get; set; }
    public string PRODUCT_NAME { get; set; }

    public int  QUANTITY{ get; set; }

    public int  DISCOUNT{ get; set; }

    public int TAX{ get; set; }

    public int PURCHASE_PRICE { get; set; }

    public int AMOUNT { get; set; }

    public static ObservableCollection<Invoice> getInvoice()
    {
        var invoice = new ObservableCollection<Invoice>();
        return invoice;
    }

}

cekilenurunadi and cekilenalisfiyati. These are what set i want of datagrid cell.

Thanks.

Answer 1

Implement INotifyPropertyChanged and raise change notifications in your Invoice class:

class Invoice : INotifyPropertyChanged
{
    public string BARKOD { get; set; }

    private string _productName;
    public string PRODUCT_NAME
    {
        get { return _productName; }
        set { _productName = value; NotifyPropertyChanged(); }
    }


    public int QUANTITY { get; set; }

    public int DISCOUNT { get; set; }

    public int TAX { get; set; }

    private int _purchasePrice;
    public int PURCHASE_PRICE
    {
        get { return _purchasePrice; }
        set { _purchasePrice = value; NotifyPropertyChanged(); }
    }

    public int AMOUNT { get; set; }

    public static ObservableCollection<Invoice> getInvoice()
    {
        var invoice = new ObservableCollection<Invoice>();
        return invoice;
    }

    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged([CallerMemberName] string propertyName = "") =>
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}

...and set the properties:

Invoice invoice = e.Row.Item as Invoice;
if (invoice != null)
{
    invoice.PRODUCT_NAME = "...";
    invoice.PURCHASE_PRICE = ...;
}