Question

在示例应用程序中，我使用了ADO.NET实体数据模型。

这是我的代码：

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    InventoryEntities context;
    context = new Inventory.InventoryEntities();
    var query = from x in context.Artikli
                select new { x.ID, x.Sifra, x.Naziv, x.Kolicina, x.Prodajna, x.Nabavna, x.UkupnoProdajna, x.UkupnoNabavna, x.Slika };
    var results = query.ToList();
    grdArtikli.ItemsSource = results;
}

private void button_Click(object sender, RoutedEventArgs e)
{
    Artikli mojID = (Artikli)grdArtikli.Items[grdArtikli.SelectedIndex];//This line raises error
    MessageBox.Show(mojID.ID.ToString());

}

还有XAML：

<Window x:Class="Inventory.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Inventory"
        mc:Ignorable="d"
        Title="MainWindow" Height="800" Width="1600" ResizeMode="NoResize" Loaded="Window_Loaded">
    <Grid>
        <TabControl x:Name="tabControl" HorizontalAlignment="Left" Height="790" Margin="0,0,0,0" VerticalAlignment="Top" Width="1590">
            <TabControl.Effect>
                <DropShadowEffect Color="#FF1A36E8"/>
            </TabControl.Effect>
            <TabItem Header="Artikli" Width="70" FontSize="18" FontWeight="Bold">
                <TabItem.Background>
                    <RadialGradientBrush>
                        <GradientStop Color="#FFF3F3F3" Offset="0"/>
                        <GradientStop Color="#FFEBEBEB" Offset="0.5"/>
                        <GradientStop Color="#FFDDDDDD" Offset="0.8"/>
                        <GradientStop Color="#FF00E2FF" Offset="1"/>
                    </RadialGradientBrush>
                </TabItem.Background>
                <Grid Background="#FFACC383">
                    <DataGrid x:Name="grdArtikli" HorizontalAlignment="Left" Margin="5,5,0,0" VerticalAlignment="Top" Width="1550" Height="650" Background="#FF78B6EC" BorderBrush="#FF72DA36" Foreground="#FFB91313" AutoGenerateColumns="False" IsReadOnly="True" MouseDoubleClick="grdArtikli_MouseDoubleClick" SelectionChanged="grdArtikli_SelectionChanged" SelectionMode="Single" SelectedIndex="0">
                        <DataGrid.Columns>
                            <DataGridTextColumn Width="80" Binding="{Binding ID}" CanUserSort="False" CanUserReorder="False" CanUserResize="False" ClipboardContentBinding="{x:Null}" Header="ID" IsReadOnly="True">
                                <DataGridTextColumn.HeaderStyle>
                                    <Style TargetType="DataGridColumnHeader">
                                        <Setter Property="HorizontalContentAlignment" Value="Center"/>
                                    </Style>
                                </DataGridTextColumn.HeaderStyle>
                            </DataGridTextColumn>
                            <DataGridTextColumn Width="100" Binding="{Binding Sifra}" ClipboardContentBinding="{x:Null}" Header="Šifra" CanUserSort="False" CanUserReorder="False" CanUserResize="False">
                                <DataGridTextColumn.HeaderStyle>
                                    <Style TargetType="DataGridColumnHeader">
                                        <Setter Property="HorizontalContentAlignment" Value="Center"/>
                                    </Style>
                                </DataGridTextColumn.HeaderStyle>
                            </DataGridTextColumn>
                            <DataGridTextColumn Width="250" Binding="{Binding Naziv}" ClipboardContentBinding="{x:Null}" Header="Naziv" CanUserSort="False" CanUserReorder="False" CanUserResize="False">
                                <DataGridTextColumn.HeaderStyle>
                                    <Style TargetType="DataGridColumnHeader">
                                        <Setter Property="HorizontalContentAlignment" Value="Center"/>
                                    </Style>
                                </DataGridTextColumn.HeaderStyle>
                            </DataGridTextColumn>
                            <DataGridTextColumn Width="100" Binding="{Binding Kolicina}" ClipboardContentBinding="{x:Null}" Header="Količina" CanUserSort="False" CanUserReorder="False" CanUserResize="False">
                                <DataGridTextColumn.HeaderStyle>
                                    <Style TargetType="DataGridColumnHeader">
                                        <Setter Property="HorizontalContentAlignment" Value="Center"/>
                                    </Style>
                                </DataGridTextColumn.HeaderStyle>
                            </DataGridTextColumn>
                            <DataGridTextColumn Width="150" Binding="{Binding Prodajna}" ClipboardContentBinding="{x:Null}" Header="Prodajna Cena" CanUserSort="False" CanUserReorder="False" CanUserResize="False">
                                <DataGridTextColumn.HeaderStyle>
                                    <Style TargetType="DataGridColumnHeader">
                                        <Setter Property="HorizontalContentAlignment" Value="Center"/>
                                    </Style>
                                </DataGridTextColumn.HeaderStyle>
                            </DataGridTextColumn>
                            <DataGridTextColumn Width="150" Binding="{Binding Nabavna}" ClipboardContentBinding="{x:Null}" Header="Nabavna Cena" CanUserSort="False" CanUserReorder="False" CanUserResize="False">
                                <DataGridTextColumn.HeaderStyle>
                                    <Style TargetType="DataGridColumnHeader">
                                        <Setter Property="HorizontalContentAlignment" Value="Center"/>
                                    </Style>
                                </DataGridTextColumn.HeaderStyle>
                            </DataGridTextColumn>
                            <DataGridTextColumn Width="150" Binding="{Binding UkupnoProdajna}" ClipboardContentBinding="{x:Null}" Header="Sum Prodajna" CanUserSort="False" CanUserReorder="False" CanUserResize="False">
                                <DataGridTextColumn.HeaderStyle>
                                    <Style TargetType="DataGridColumnHeader">
                                        <Setter Property="HorizontalContentAlignment" Value="Center"/>
                                    </Style>
                                </DataGridTextColumn.HeaderStyle>
                            </DataGridTextColumn>
                            <DataGridTextColumn Width="150" Binding="{Binding UkupnoNabavna}" ClipboardContentBinding="{x:Null}" Header="Sum Nabavna" CanUserSort="False" CanUserReorder="False" CanUserResize="False">
                                <DataGridTextColumn.HeaderStyle>
                                    <Style TargetType="DataGridColumnHeader">
                                        <Setter Property="HorizontalContentAlignment" Value="Center"/>
                                    </Style>
                                </DataGridTextColumn.HeaderStyle>
                            </DataGridTextColumn>
                            <DataGridTemplateColumn CanUserReorder="False" CanUserResize="False" ClipboardContentBinding="{x:Null}" Header="Slika" Width="*">
                                <DataGridTemplateColumn.HeaderStyle>
                                    <Style TargetType="DataGridColumnHeader">
                                        <Setter Property="HorizontalContentAlignment" Value="Center"/>
                                    </Style>
                                </DataGridTemplateColumn.HeaderStyle>
                                <DataGridTemplateColumn.CellTemplate>
                                    <DataTemplate>
                                        <Image Source="{Binding Slika}" Stretch="Fill" Width="Auto" Height="30" x:Name="mojaSlika" Loaded="mojaSlika_Loaded">

                                        </Image>
                                    </DataTemplate>
                                </DataGridTemplateColumn.CellTemplate>
                            </DataGridTemplateColumn>
                        </DataGrid.Columns>
                        <DataGrid.DataContext>
                            <local:Artikli Naziv="0" Sifra="0" UkupnoNabavna="0" UkupnoProdajna="0"/>
                        </DataGrid.DataContext>

                    </DataGrid>
                    <Button x:Name="button" Content="Button" HorizontalAlignment="Left" Margin="423,693,0,0" VerticalAlignment="Top" Width="75" Click="button_Click"/>

                </Grid>
            </TabItem>
            <TabItem Header="TabItem">
                <Grid Background="#FFE5E5E5"/>
            </TabItem>
        </TabControl>
    </Grid>
</Window>

在以下行的button_click事件中：Artikli mojID = (Artikli)grdArtikli.Items[grdArtikli.SelectedIndex];我收到InvalidCastException：

无法转换类型为<< f__AnonymousType0 9[System.Int32,System.String,System.String,System.Int32,System.Single,System.Single,System.Nullable 1 [System.Single]，System.Nullable`1 [System.Single]，System.Byte []]类型的对象来键入“ Inventory.Artikli”

怎么了？

Answer 1

此行：

select new { x.ID, x.Sifra, x.Naziv, x.Kolicina, x.Prodajna, x.Nabavna, x.UkupnoProdajna, x.UkupnoNabavna, x.Slika };

返回包含这些字段的匿名对象，即列表中的内容。更改此值以实例化一个类，或者不要将该项目投影到其他对象。

例如，尝试：

context.Artikli.ToList()

代替Linq。

Answer 2

我认为您的问题是

var query = from x in context.Artikli
                select new { x.ID, x.Sifra, x.Naziv, x.Kolicina, x.Prodajna, x.Nabavna, x.UkupnoProdajna, x.UkupnoNabavna, x.Slika };

这是一个匿名类型，然后尝试将其回退为Artikli类型。如果您从查询中删除“新建”和特定字段，（可能需要调整绑定），这将允许您再次将其投射回去。

所选行中的C＃DataGrid单元格值

2 个答案: