How can edit single column on bind gridview with excel using asp.net c# in web application

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C#

ASP.NET

MS-Excel

Gridview

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Dear all,
I have bind Gridview with excel sheet.
My Code given below:

.aspx file

<div>
        <asp:DropDownList ID="ddlCategories" runat="server"
             AutoPostBack="true"
             OnSelectedIndexChanged="ddlCategories_SelectedIndexChanged" Width="300px">
        
    </div>
     <div>
        <asp:GridView ID="gvProducts" runat="server" BackColor="#DEBA84"
                BorderColor="#DEBA84"
            BorderStyle="None" BorderWidth="1px" CellPadding="3" 
                CellSpacing="2">
            <footerstyle backcolor="#F7DFB5" forecolor="#8C4510" />
            <HeaderStyle BackColor="#A55129" Font-Bold="True" 
                ForeColor="White" />
            <pagerstyle forecolor="#8C4510" horizontalalign="Center" />
            <rowstyle backcolor="#FFF7E7" forecolor="#8C4510" />
            <SelectedRowStyle BackColor="#738A9C" Font-Bold="True"
                 ForeColor="White" />
            <sortedascendingcellstyle backcolor="#FFF1D4" />
            <sortedascendingheaderstyle backcolor="#B95C30" />
            <sorteddescendingcellstyle backcolor="#F1E5CE" />
            <sorteddescendingheaderstyle backcolor="#93451F" />
        
    </div>      

Code behind:

protected void Page_Load(object sender, EventArgs e)
    {

        if (!Page.IsPostBack)
        {
            OleDbConnection oconn = null;
            string FilePath = "D:\\HBL Current Work\\HBLMBI\\Forms\\dotnetmentors\\Products.xlsx";
            oconn = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0; Data Source=" + FilePath + ";Extended Properties=Excel 8.0");

            DataTable dtCategories = new DataTable();
            oconn.Open();
            dtCategories = oconn.GetOleDbSchemaTable(
                        OleDbSchemaGuid.Tables, null);
            oconn.Close();

            List<listitem> lstCategories = new List<listitem>();

            string sheetName = string.Empty;
            foreach (DataRow dr in dtCategories.Rows)
            {
                sheetName = dr["TABLE_NAME"].ToString();
                if (!sheetName.Contains("Sheet"))
                    lstCategories.Add(new ListItem(
                                sheetName.Replace("$", "")));
            }
            ddlCategories.DataSource = lstCategories;
            ddlCategories.DataBind();
        }

    }


    protected void ddlCategories_SelectedIndexChanged(object sender, EventArgs e)
    {

        DataTable dtProducts = new DataTable();

        OleDbConnection oconn = null;
        string FilePath = "D:\\HBL Current Work\\HBLMBI\\Forms\\dotnetmentors\\Products.xlsx";
        oconn = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0; Data Source=" + FilePath + "; Extended Properties=Excel 8.0");
        OleDbCommand ocmd = new OleDbCommand("select * from [" + ddlCategories.SelectedItem.Value + "$]", oconn);

        oconn.Open();
       // ocmd.ExecuteNonQuery();
        OleDbDataAdapter dr = new OleDbDataAdapter();
        dr.SelectCommand = ocmd;
        dr.Fill(dtProducts);

        oconn.Close();
        gvProducts.DataSource = dtProducts;
        gvProducts.DataBind();  


    }

Now I want to edit single column data of entire row and then rebind the gridview with modify data. How can I solved this problem. Help to me