Multiple Groups with Different Header Templates

[Francisco Amador]

In my grid I am attempting to group by a certain column, but display a different value in the group header. For this I found a solution in the forum that uses an IValueConverter. Unfortunately, in my grid I will have to group by two different columns like this at the same time. The grouping will occur programmatically. Is there a way to let the value converter know what the name of the column being grouped on is?

I haven't been able to come up with a way on my own, but I'm assuming it would come in through the ConverterParameter somehow. I just don't know how. The grid row object contains the description that I want to display so if there is a way to pass this information into the converter that would be the least expensive way of displaying it. Any ideas on this?

[Vlad]

Hi,

Why not use GroupHeaderTemplate property of the columns similar to this demo?

Best wishes,
Vlad
the Telerik team

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[Francisco Amador]

Thank you for pointing me in that direction, I had not seen that example before. I have not worked with aggregate functions before so I didn't know that you could use them for my purpose. That will work for what I need, however I'm still working out how to use the FirstFunction to display the value I need. When I have the FirstFunction aggregate declared in the GridViewDataColumn that I wish to display, it just shows the namespace name of the class of the row item ("BNS.DataObjects.CatalogItem"). How can I get it to display the value of a specific property from that first item?

[Francisco Amador]

Actually, after trying it out with both of the columns that I need to do this for, Aggregate functions will not work since they will appear in all the group rows. The current code that I'm playing around with is:

<telerikGridView:GridViewDataColumn DataMemberBinding="{Binding RegionCode}" Header="Category" IsVisible="False">
    <telerikGridView:GridViewDataColumn.GroupHeaderTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Group.Items[0].RegionDesc}" />
        </DataTemplate>
    </telerikGridView:GridViewDataColumn.GroupHeaderTemplate>
</telerikGridView:GridViewDataColumn>

I know that the "Binding Group.Items[0].RegionDesc" will not work, but is there a way to grab the value of RegionDesc from the RegionCode GroupHeaderTemplate?

[Francisco Amador]

Sorry, I went on a tangent on my last two posts without taking a closer look at what I had from my original question. I put an IValueConverter for each of the columns that I need like this:

<converters:CategoryCodeConverter x:Key="CategoryCodeConverter"/>
    <converters:RegionCodeConverter x:Key="RegionCodeConverter"/>

    <DataTemplate x:Key="GroupHeaderCategoryCodeTemplate">
        <TextBlock Text="{Binding Group.Key, Converter = {StaticResource CategoryCodeConverter}}" />
    </DataTemplate>

I then used the template as usual

<telerikGridView:GridViewDataColumn DataMemberBinding="{Binding CategoryCode}" Header="Category" IsVisible="False" GroupHeaderTemplate="{StaticResource GroupHeaderCategoryCodeTemplate}" />

If someone using this post for help has never used an IValueConverter, here is the structure

public class SomethingConverter : IValueConverter
        {
            public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
            {
                    return Something;
            }

            public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
            {
                return Something;
            }
    }

Thanks for your help
Francisco Amador