Question

我在通过mvvm模式使用ICommand从数据库填充列表视图时遇到问题。我错过了一些简单的东西，或者我没有以正确的方式编写代码。

当我在没有ICommand的情况下尝试它时，它可以工作，但是ICommand并不是问题，因为它可以通过显示MessageBox来工作。

错误： System.Windows.Data信息：10：无法使用绑定检索值，并且不存在有效的后备值；请参见使用默认值代替。 BindingExpression：Path = NonFrozenColumnsViewportHorizontalOffset; DataItem = null;目标元素是“ ColumnDefinition”（HashCode = 40158284）；目标属性为“宽度”（类型为“ GridLength”）

 <ListView x:Name="listViewPorducts" Grid.Column="1" Margin="0" ScrollViewer.HorizontalScrollBarVisibility="Disabled" Grid.Row="2" ItemsSource="{Binding ProductsListView}"  BorderThickness="1">
            <ListView.ItemTemplate>
                <DataTemplate>

                    <Grid >                                
                        <TextBlock Name="itemName" Grid.Row="0"  Margin="0,0,0,4" Text="{Binding Path=product_name}" FontSize="16" FontFamily="Calibri" TextWrapping="Wrap" TextTrimming="WordEllipsis" Background="#FFB2ACAC" HorizontalAlignment="Stretch"/>
                        <Separator HorizontalContentAlignment="Stretch" VerticalAlignment="Bottom"/>
                        <StackPanel Grid.Row="1" Orientation="Horizontal" Margin="0,3,0,3">
                            <TextBlock Name="categoryType" Text="{Binding Path=category_name}" HorizontalAlignment="Stretch" FontSize="14" FontFamily="Calibri"/>
                            <TextBlock  Grid.Row="1" Text="->" Margin="4,0,4,0" FontSize="14" FontFamily="Calibri"/>
                            <TextBlock Name="itemBrand"   Text="{Binding Path=brand_name}" HorizontalAlignment="Stretch" FontSize="14" FontFamily="Calibri"/>
                        </StackPanel>
                        <TextBlock Name="itemPrice" Grid.Row="2" Margin="0,3,0,3"  Text="{Binding Path=list_price, StringFormat={}{0:C}}" FontSize="16" FontFamily="Calibri" FontWeight="Bold" HorizontalAlignment="Left"/>            
                    </Grid>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

// Class1

 DataTable dataTable;

    public DataView ProductsListView { get; private set; }

 public void GetData()
    {

        string conStr = ConfigurationManager.ConnectionStrings["EYEWEAR"].ToString();        

        try
        {
            SqlConnection sqlCon = new SqlConnection(conStr);
            dataTable = new DataTable();

            if (sqlCon.State == ConnectionState.Closed)
            {
                sqlCon.Open();
                using (SqlDataAdapter adapter = new SqlDataAdapter())
                {
                    adapter.SelectCommand = new SqlCommand("SELECT  p.product_name, ct.category_name, bt.brand_name, p.list_price FROM dbo.products p LEFT JOIN brands_Table bt ON p.brand_id = bt.brand_id LEFT JOIN categoriesTable ct ON p.category_id = ct.category_id; ", sqlCon);
                    adapter.Fill(dataTable);
                   ProductsListView = dataTable.DefaultView;

                }
            }
            sqlCon.Close();
        }
        catch (Exception e)
        {
            MessageBox.Show(e.Message);
        }
    }

// ShowFrames：ICommand

   public void Execute(object parameter)
        {
            MessageBox.Show("Click command works.");
            class1.GetData();
        }

无法使用wpf mvvm模式从数据库填充列表视图？

0 个答案: