Import Excel with Parent Child relationship data to database in ASP.Net

Here I have created Sample that will help you out.

HTML

<div>
    <asp:FileUpload ID="FileUpload1" runat="server" />
    <asp:Button ID="btnImport" runat="server" Text="Import" OnClick="ImportExcel" />
    <hr />
    <asp:GridView ID="GridView1" runat="server">
    </asp:GridView>
</div>

C#

static string ComponentId = string.Empty;
protected void ImportExcel(object sender, EventArgs e)
{
    string filePath = Server.MapPath("~/Files/") + Path.GetFileName(FileUpload1.PostedFile.FileName);
    FileUpload1.SaveAs(filePath);
    using (SpreadsheetDocument doc = SpreadsheetDocument.Open(filePath, false))
    {
        Sheet sheet = doc.WorkbookPart.Workbook.Sheets.GetFirstChild<Sheet>();
        Worksheet worksheet = (doc.WorkbookPart.GetPartById(sheet.Id.Value) as WorksheetPart).Worksheet;
        IEnumerable<Row> rows = worksheet.GetFirstChild<SheetData>().Descendants<Row>();
        DataTable dt = new DataTable();
        List<Component> components = new List<Component>();
        foreach (Row row in rows)
        {
            if (row.RowIndex.Value == 1)
            {
                foreach (Cell cell in row.Descendants<Cell>())
                {
                    dt.Columns.Add(GetValue(doc, cell));
                }
            }
            else
            {
                dt.Rows.Add();
                int i = 0;
                string xml = row.InnerXml;
                if (!xml.Contains("A"))
                {
                    dt.Rows[dt.Rows.Count - 1][i] = string.Empty;
                    i++;
                }
                foreach (Cell cell in row.Descendants<Cell>())
                {
                    if (GetColumnName(cell.CellReference) == "A")
                    {
                        ComponentId = GetValue(doc, cell);
                    }
                    dt.Rows[dt.Rows.Count - 1][i] = GetValue(doc, cell);
                    i++;
                }
                components.Add(new Component
                {
                    ComponentId = dt.Rows[dt.Rows.Count - 1]["ComponentId"].ToString(),
                    ComponentFunctionality = dt.Rows[dt.Rows.Count - 1]["ComponentFunctionality"].ToString(),
                    DerivedResult = dt.Rows[dt.Rows.Count - 1]["DerivedResult"].ToString(),
                    ExpectedResult = dt.Rows[dt.Rows.Count - 1]["ExpectedResult"].ToString(),
                    ParentComponentId = ComponentId
                });
            }
        }
        var grpComp = from comp in components
                        group comp by comp.ParentComponentId into eGroup
                        select new
                        {
                            Key = eGroup.Key,
                            Components = eGroup
                        };

        List<Component> resultComponent = new List<Component>();
        foreach (var c in grpComp)
        {
            Component co = c.Components.Where(x => x.ComponentId == c.Key).FirstOrDefault();
            co.ChildComponent = c.Components.Where(comp => comp.ParentComponentId == c.Key).Where(cm => cm.ComponentId == string.Empty).ToList<Component>();
            resultComponent.Add(co);
        }

        // To Save into Database
        InsertComponent(resultComponent);
        //I have simply shown into Grid if you want you can bind to nested Grid
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
}

private void InsertComponent(List<Component> components)
{
    foreach (Component comp in components)
    {
        //Write code to Insert into Parent Table
        foreach (Component childComp in comp.ChildComponent)
        {
            //Write code to Insert into Child Table    
        }
    }
}

public static string GetColumnName(string cellReference)
{
    Regex regex = new Regex("[A-Za-z]+");
    Match match = regex.Match(cellReference);
    return match.Value;
}

private string GetValue(SpreadsheetDocument doc, Cell cell)
{
    string value = cell.CellValue.InnerText;
    if (cell.DataType != null && cell.DataType.Value == CellValues.SharedString)
    {
        return doc.WorkbookPart.SharedStringTablePart.SharedStringTable.ChildElements.GetItem(int.Parse(value)).InnerText;
    }
    return value;
}

Component Class

public class Component
{
    public Component()
    {
        ChildComponent = new List<Component>();
    }
    public string ParentComponentId { get; set; }
    public string ComponentId { get; set; }
    public string ComponentFunctionality { get; set; }
    public string ExpectedResult { get; set; }
    public string DerivedResult { get; set; }
    public List<Component> ChildComponent { get; set; }
}

Screenshot

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