Using the functionality of SummaryDescriptions, I found it difficult to implement the functionality I wanted.
So, I'm going to use two grids.

But if I scroll horizontally on grid1, can I make grid2 scroll with it?

One additional question is, can I use a datagrid without headers?
If not, how to hide the header?

public class CustomDomestic : SummaryCalculator
    {
        private float m_fData = 1.0f;
        public int countries;
        public string m_strDspName;

        public CustomDomestic(string DspName)
        {
            this.DispName = DspName;
        }

        public CustomDomestic()
        {
            this.DispName = this.PropertyName;
        }


        public string DispName
        {
            get
            {
                return m_strDspName;
            }
            set
            {
                m_strDspName = value;
            }
        }

        public override string DisplayName
        {
            get
            {
                return m_strDspName;
            }
        }

        public override void BeginCalculation(IDataSource dataSource, string propertyName)
        {
            base.BeginCalculation(dataSource, propertyName);
            this.countries = 0;
        }

        public override void Aggregate(object item)
        {
            Console.WriteLine("Aggregate: " + item);
            var contents = item as Employee;

            m_fData *= contents.KPI;


            //this.countries++;
            //if (item = "KPI")
            //{
            //    this.countries++;
            //}
        }

        public override ISummaryResult EndCalculation()
        {
            //eturn 1;

            return new DefaultSummaryResult(
                this.PropertyName,
                SummaryOperand.Custom,
                string.Format("{0}\n{1}",100, 200));
        }
    }

   <ig:XamDataGrid.SummaryDescriptions>


                <ig:ColumnSummaryDescription
                    Operand="Custom"
                    PropertyPath="Name"
                    ProvideCalculator="ColumnSummaryDescription_ProvideCalculator_1" />

                <ig:ColumnSummaryDescription
                    Operand="Custom"
                    PropertyPath="Name"
                    ProvideCalculator="ColumnSummaryDescription_ProvideCalculator_2" />

Thank you for answer. I have too many questions to ask

First
I put the same attribute twice, but the result is not printed. Can't I put custom twice in a row?

In the second EndCalculation output, only DisplayName is printed, but I want to center it. And I want to print only the values from the second column.

Add 

I have explained a lot about my development direction and I think you will understand.

Can you make a simple example?

Hello,

I’m not sure I can recommend using multiple grids in this case as they will be independent of each other, and there are no public events/methods that detect when the scroll has changed on the grid at this time. We do have some methods that allow you to scroll rows and columns into view, but there is no way to synchronize the scrolling at the moment between two grids.

Regarding the grid without headers, you can do this by setting the HeaderHeight property of the grid to 0.

It is worth noting that each of the ColumnSummaryDescriptions has a ProvideCalculator event that you might be able to use to get a visual like you are looking for. The event arguments of that event allows you to provide your own custom derived SummaryCalculator to do the summaries how you would like and control things like the DisplayName of the calculator. This would still require you to add a ColumnSummaryDefinition for each of your columns, as there is no “grid-wide” summary in the XamDataGrid in our Xamarin toolset, but I believe this could get you closer to the visualization that you are looking for than using multiple grids would.

Please let me know if you have any other questions or concerns on this matter.