DataGrid复制两列

时间：2015-05-05 17:34:16

标签： c# wpf datagrid

我需要社区的帮助。我试图在DataGrid（WPF和C＃）中乘以两列的值，第一列从MySql数据库获取其数据，第二列是输入值，用户将键入一个应与数字相乘的数字第一列和结果应显示在名为＆＃34; Total＆＃34;的第三列中。我已经搜索过所有尝试过几乎相同的其他人的不同方法，但我只是不能得到乘法的值，结果出现在第三列。这是我尝试过的最后一段代码，我不得不提到我对C＃和WPF还很新，但经验并不多：

<DataGrid AutoGenerateColumns="False" x:Name="tblData" Margin="30,197,7,0" Grid.Row="1" VerticalAlignment="Top" Height="510" Grid.ColumnSpan="4"
              BorderThickness="2" BorderBrush="#FF445BBF" ItemsSource="{Binding Path=LoadDataBinding}" CanUserResizeRows="False" ClipToBounds="True"
              CanUserSortColumns="False" HorizontalGridLinesBrush="#FFC7C7C7" VerticalGridLinesBrush="#FFC7C7C7" IsManipulationEnabled="True" EnableRowVirtualization="False" 
              IsTextSearchEnabled="True" xmlns:local="clr-namespace:PoS_Pimentel">
        <DataGrid.Resources>
            <local:AmmountConverter x:Key="AmmountConverter" />
        </DataGrid.Resources>
        <DataGrid.Columns>
            <DataGridTextColumn Binding="{Binding Path=nomprod}" Header="Producto" Width="500" IsReadOnly="True">
                <DataGridTextColumn.HeaderStyle>
                    <Style TargetType="DataGridColumnHeader">
                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                        <Setter Property="FontSize" Value="14" />
                    </Style>
                </DataGridTextColumn.HeaderStyle>
            </DataGridTextColumn>
            <DataGridTextColumn Binding="{Binding Path=preciogram, Mode=TwoWay}" Header="Precio por Gramo" Width="190" IsReadOnly="True">
                <DataGridTextColumn.HeaderStyle>
                    <Style TargetType="DataGridColumnHeader">
                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                        <Setter Property="FontSize" Value="14" />
                    </Style>
                </DataGridTextColumn.HeaderStyle>
            </DataGridTextColumn>
            <DataGridTextColumn Binding="{Binding Path=gramos, Mode=TwoWay}" Header="Gramos" Width="190" IsReadOnly="False">
                <DataGridTextColumn.HeaderStyle>
                    <Style TargetType="DataGridColumnHeader">
                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                        <Setter Property="FontSize" Value="14" />
                    </Style>
                </DataGridTextColumn.HeaderStyle>
            </DataGridTextColumn>
            <DataGridTextColumn Binding="{Binding Path=total, Mode=TwoWay}" Header="Total" Width="*" IsReadOnly="True">
                <DataGridTextColumn.HeaderStyle>
                    <Style TargetType="DataGridColumnHeader">
                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                        <Setter Property="FontSize" Value="14" />
                    </Style>
                </DataGridTextColumn.HeaderStyle>
            </DataGridTextColumn>
        </DataGrid.Columns>
    </DataGrid>

在C＃端，我为EntitiyClass和AmmountConverter类创建了两个单独的.cs文件：

EntityClass代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.ComponentModel;
using System.Collections.ObjectModel;
using System.Windows.Forms;

namespace PoS
{
    #region
    public class Entity_Class : INotifyPropertyChanged
    {
        private int _preciogram;
        public int PrecioGram
        {
            get { return _preciogram; }
            set { _preciogram = value; NotifyPropertyChanged("gramos"); }
        }

        private int _gramos;
        public int Gramos
        {
            get { return _gramos; }
            set { _gramos = value; NotifyPropertyChanged("gramos"); }
        }

        public event PropertyChangedEventHandler PropertyChanged;
        private void NotifyPropertyChanged(string propertyName)
        {
            if(PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}

和AmmountConverter类：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;

namespace PoS_Pimentel
{
    public class AmmountConverter : IMultiValueConverter
    {
        public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            double prcgrms = values[1] == null ? 0 : System.Convert.ToDouble(values[1]);
            double grms = values[2] == null ? 0 : System.Convert.ToDouble(values[2]);

            return prcgrms * grms;
        }

        public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}

我不是很擅长这个，但我正在努力，任何指针都会非常感激。谢谢大家。

2 个答案:

答案 0 :(得分：3)

您无需使用转换器进行此计算。希望你能在Model Class中处理它。您还需要绑定到属性。 DataGrid绑定属性名称不正确c＃区分大小写。请参阅下面的代码。

 <DataGrid x:Name="dgr" AutoGenerateColumns="False" ItemsSource="{Binding LoadDataBinding}">           
        <DataGrid.Columns>                
            <DataGridTextColumn Binding="{Binding Path=PrecioGram, Mode=TwoWay}" Header="Precio por Gramo" Width="190" IsReadOnly="True">
                <DataGridTextColumn.HeaderStyle>
                    <Style TargetType="DataGridColumnHeader">
                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                        <Setter Property="FontSize" Value="14" />
                    </Style>
                </DataGridTextColumn.HeaderStyle>
            </DataGridTextColumn>
            <DataGridTextColumn Binding="{Binding Path=Gramos, Mode=TwoWay}" Header="Gramos" Width="190" IsReadOnly="False">
                <DataGridTextColumn.HeaderStyle>
                    <Style TargetType="DataGridColumnHeader">
                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                        <Setter Property="FontSize" Value="14" />
                    </Style>
                </DataGridTextColumn.HeaderStyle>
            </DataGridTextColumn>
            <DataGridTextColumn Header="Total" Width="100" Binding="{Binding Total}">
                <DataGridTextColumn.HeaderStyle>
                    <Style TargetType="DataGridColumnHeader">
                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                        <Setter Property="FontSize" Value="14" />
                    </Style>
                </DataGridTextColumn.HeaderStyle>

            </DataGridTextColumn>
        </DataGrid.Columns>
    </DataGrid>

 public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = new MainViewModel();
    }

}

public class MainViewModel
{
    private ObservableCollection<Entity_Class> myVar = new ObservableCollection<Entity_Class>();

    public ObservableCollection<Entity_Class> LoadDataBinding
    {
        get { return myVar; }
        set { myVar = value; }
    }

    public MainViewModel()
    {
        for (int i = 1; i < 10; i++)
        {
            LoadDataBinding.Add(new Entity_Class() { PrecioGram=i});
        }
    }
}   

public class Entity_Class : INotifyPropertyChanged
{
    private int _preciogram;
    public int PrecioGram
    {
        get { return _preciogram; }
        set { _preciogram = value; NotifyPropertyChanged("PrecioGram"); }
    }

    private int _gramos;
    public int Gramos
    {
        get { return _gramos; }
        set
        { 
            _gramos = value; NotifyPropertyChanged("gramos");
            Total = _preciogram * _gramos;
        }
    }

    private int _total;
    public int Total
    {
        get { return _total; }
        set { _total = value; NotifyPropertyChanged("Total"); }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    private void NotifyPropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

答案 1 :(得分：1)

有两种方法可以实现这一点，看起来你正试图混合使用它们。

一种方法是将所有3列绑定到数据对象上的属性，并在用户输入的属性上使用PropertyChange事件处理程序来重新计算总列。这通常是我的偏好。

<DataGridTextColumn Binding="{Binding Value1}" />
<DataGridTextColumn Binding="{Binding Value2}" />
<DataGridTextColumn Binding="{Binding Total}" />

private void MyDataItem_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
    if (e.PropertyName == "Value2")
        Total = Value1 * Value2;
}

采用这种方法，不需要转换器。

另一种方法是不绑定第3列，并使用转换器显示它

<!-- Note: syntax may be incorrect here -->
<DataGridTextColumn Binding="{Binding Value1}" />
<DataGridTextColumn Binding="{Binding Value2}" />
<DataGridTextColumn>
    <DataGridTextColumn.Binding>
        <Multibinding Converter="{StaticResource MyMultiplicationConverter}">
            <Binding Path="Value1" />
            <Binding Path="Value2" />
        </Multibinding>
    <DataGridTextColumn.Binding>
</DataGridTextColumn>

在这种情况下，我们将两列绑定到数据模型上的值，第三列使用转换器将两个值转换为不同的第三个值。

应该注意的是，无论您使用哪种方法，TextBox的默认绑定模式只是更新LostFocus上的源，因此我们不会引发过多的更改通知。如果您希望在用户输入数据时实时更新，则应将绑定模式更改为PropertyChanged或write your own binding update behavior to update the bound source after a short delay。

另外作为旁注，您正在为PrecioGram属性中的错误属性提出PropertyChange通知：

public int PrecioGram
{
    get { return _preciogram; }
    set 
    { 
        _preciogram = value; 
        NotifyPropertyChanged("gramos"); // Incorrect property here
    }
}
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