C# Display DataGridView Rows Based on Similar ID from sql server

Question

Display DataGridView Rows Based on Similar ID. My seem problem

Answer 1

Simple group-by to see if there are duplicates. And rather than me write an elaborate code sample

• Linq groupby on datatables
• DataTable group by and iterate through C#

using System.Data;

namespace WinFormsApp1;

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        dataGridView1.DataSource = MockedDataTable();
    }

    private void GroupByIdButton_Click(object sender, EventArgs e)
    {
        dataGridView2.DataSource = GroupData((DataTable)(dataGridView1.DataSource));
    }

    public static DataTable GroupData(DataTable dt) =>
        dt.AsEnumerable()
            .GroupBy(row => row.Field<int>("id"))
            .Select(g => 
                g.OrderBy(r => r.Field<int>("id")).First())
            .CopyToDataTable();

    public static DataTable MockedDataTable()
    {
        var table = new DataTable();

        table.Columns.Add(new DataColumn("Id", typeof(int)));
        table.Columns.Add(new DataColumn("TaxRate", typeof(decimal)));
        table.Columns.Add(new DataColumn("Value", typeof(decimal)));
        table.Columns.Add(new DataColumn("TaxAmount", typeof(decimal)));
        table.Columns.Add(new DataColumn("FinalValue", typeof(decimal), "Value + TaxAmount"));

        table.Rows.Add(1, 5, 1000, 50);
        table.Rows.Add(1, 5, 2000, 100);
        table.Rows.Add(1, 10, 1000, 100);
        table.Rows.Add(2, 10, 2000, 200);
        table.Rows.Add(1, 15, 1000, 150);
        table.Rows.Add(2, 15, 2000, 300);

        return table;

    }
}