CODEWITHSUNDEEP
c#wpfdatagridsumgrouping
Andrzej Aksak
Andrzej Aksak

Reputation: 11

how to add sum of values in datagrid with grouping WPF c#

Hello i'm weary beginning in coding and this is my first serious application. I have data grid with grouping and I want to add in each group sum of values from column to make it to look like this https://leeontech.files.wordpress.com/2010/02/final.png

I have try to use many solutions from internet but nothing work for me:

My XML

 <DataGrid x:Name="GridRaport" CanUserAddRows="False" VerticalAlignment="Stretch" MinWidth="500" AlternatingRowBackground="LightBlue"  AlternationCount="2" Margin="20,20,20,20">
                    <DataGrid.GroupStyle>
                        <GroupStyle>
                            <GroupStyle.ContainerStyle>
                                <Style TargetType="{x:Type GroupItem}">
                                    <Setter Property="Template">
                                        <Setter.Value>
                                            <ControlTemplate TargetType="{x:Type GroupItem}">
                                                <StackPanel >
                                                    <StackPanel Orientation="Horizontal">
                                                        <TextBlock Margin="10,10,10,10" Text="{Binding Name}" FontWeight="Bold" />
                                                        <TextBlock  Margin="30,10,10,10"  Text="{Binding ItemCount, StringFormat=Liczba wycieczek: {0}}" FontWeight="Bold"  />

                                                    </StackPanel>
                                                    <ItemsPresenter />
                                                </StackPanel>
                                            </ControlTemplate>
                                        </Setter.Value>
                                    </Setter>
                                </Style>
                            </GroupStyle.ContainerStyle>
                        </GroupStyle>
                    </DataGrid.GroupStyle>
                </DataGrid>

And my Code behind

private void FillGridRaport()
    {

        string CmdString = string.Empty;
        using (SqlConnection con = new SqlConnection(ConString))
        {
            CmdString = "Long query";
            SqlCommand cmd = new SqlCommand(CmdString, con);
            SqlDataAdapter sda = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable("Wycieczki");
            sda.Fill(dt);
            DataView dataView = dt.AsDataView();
            BindingListCollectionView cv = CollectionViewSource.GetDefaultView(dataView) as BindingListCollectionView;
            PropertyGroupDescription groupDescription1 = new PropertyGroupDescription();
            groupDescription1.PropertyName = "Pracownik";
            cv.GroupDescriptions.Add(groupDescription1);
            GridRaport.ItemsSource = cv;    
}
    }

I will be weary grateful for your help

Upvotes: 1

Views: 1387

Answers (1)

J.H.
J.H.

Reputation: 4322

To get the sum, you need a converter. Make a class that implements IValueConverter, add it as a resource with a key and then reference it in the XAML.

Here is an example converter, I have it setup to take the field name as the ConverterParameter.

public class SumValues : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        var cvg = value as CollectionViewGroup;
        var field = parameter as string;
        if (cvg == null || field == null)
            return null;

        // Double field
        return cvg.Items.Sum(r => (double)(r as DataRowView)[field]);
        // Or, if the field is nullable
        //return cvg.Items.Sum(r => (r as DataRowView)[field] as double?); // "as" can return null so we have to use "double?"

        // More complex example - string field that needs to be converted to a long
        //return cvg.Items.Sum(r => long.Parse((r as DataRowView)[field].ToString()));
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

Add the converter as a resource, either in App.xaml or locally to the DataGrid:

<DataGrid.Resources>
    <local:SumValues x:Key="SumValues" />
</DataGrid.Resources>

And, finally, add the textblock to your GroupItem's ControlTemplate:

<TextBlock  Margin="60,10,10,10"  Text="{Binding StringFormat=Sum: {0}, Converter={StaticResource SumValues}, ConverterParameter=MyDataSetFieldName}" FontWeight="Bold"  />

Upvotes: 4

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