How to perform DML operations on a Dataset / DataTable and save to database

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C#

ASP.NET

Hi,
Here i am trying to load a Excel file to a grid view without saving to the database.
I need to perform DML operations on the grid that is saved in a DataSet / DataTable.
I dont have any idea of performing operations on a dataset and here i am saving the whole excel sheet in a ViewState and assiging it to gridview.
Any one have idea of performing DML operations on a DataSet/DataTable. If So, helpme out in this aspect.

Thank You.

This is the process i am following
First:

Loading excel to gridview

DataTable _dtTable = new DataTable();
        DataSet _objDs = new DataSet();
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            if (FileUpload1.HasFile)
            {
                OleDbConnection connection = null;
                string excelPath = ConfigurationManager.AppSettings["ExcelPath"].ToString();
                excelPath = excelPath + FileUpload1.PostedFile.FileName;
                ViewState["ExcelSheetName"] = FileUpload1.PostedFile.FileName;
                FileUpload1.SaveAs(excelPath);
                string FileType = FileUpload1.PostedFile.FileName.Substring(FileUpload1.PostedFile.FileName.LastIndexOf("."));
                if (FileType == ".xlsx")
                {
                    connection = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;" + "Data Source=" + excelPath + ";" + "Extended Properties=Excel 12.0 Xml;");
                }
                else if (FileType == ".xls")
                {
                    connection = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + excelPath + ";" + "Extended Properties=Excel 8.0;");
                }
                connection.Open();
                OleDbCommand ocmd = new OleDbCommand("SELECT * FROM [Sheet1$]", connection);
                OleDbDataAdapter da = new OleDbDataAdapter(ocmd);
                da.Fill(_objDs);
                _dtTable = _objDs.Tables[0];
                Label1.Text = "Total No.Records:";
                lblcount.Text = _dtTable.Rows.Count.ToString();
                ViewState["PinsTable"] = _dtTable;
                GridView1.DataSource = _dtTable;
                GridView1.DataBind();
            }


Second:

protected void btnSubmit_Click(object sender, EventArgs e)
        {
            string connectionString = "";
            DataTable _dt = (DataTable)ViewState["PinsTable"];
// This is where i was struck ed

I have idea of grid editing but here it is different scenario.
Here i have to do some DML operations on the datatable and this has to be saved to the database not the Excel sheet data only the gridview data.