Dynamically creating a dropdown, with values from SQL server

I want to create a feature within my program that when i load in an excel file, it counts how many columns in the spreadsheet and dynamically creates a dropdown for each and every column, to select what header it should be, and bind it to the GridView .Data from SQL server will populate the dropdowns. Some problems i have run into is, how do i have a button where it asks for the file location? i have tried this way to load in a hardcoded location, but it doesnt work.

Sub SubmitBtn_Excel(Sender As Object, E As EventArgs)
        Try
            Dim MyConnection As System.Data.OleDb.OleDbConnection
            Dim dataSet As System.Data.DataSet
            Dim MyCommand As System.Data.OleDb.OleDbDataAdapter
            Dim path As String = "C:\\spreadsheet.xlsx"

            MyConnection = New System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=Excel 12.0;")
            MyCommand = New System.Data.OleDb.OleDbDataAdapter("select * from [Sheet1$]", MyConnection)

            dataSet = New System.Data.DataSet
            MyCommand.Fill(dataSet)
            GridView1.DataSource = dataSet.Tables(0)

            MyConnection.Close()
        Catch ex As Exception

        End Try

    End Sub

I also have a method to call on the database with the table i have created to populate the data, should i put this method all in one method with the excel call?? considering that the dropdown id was dynamically created, it doesnt know how to find it because its not id'd in the HTML

Protected Sub Page_Load(sender As Object, e As EventArgs)
        If Not Page.IsPostBack Then
            FillDeptDropdownList()
        End If
    End Sub
    Protected Sub FillDeptDropdownList()
        Dim con As New SqlConnection(ConfigurationManager.ConnectionStrings("MyDbCon").ConnectionString)

        Dim cmd As New SqlCommand("Select * from demofeepay.dbo.catagories", con)
        Dim adp As New SqlDataAdapter(cmd)
        Dim dt As New DataTable()
        adp.Fill(dt)
        ddlDynamic.DataSource = dt
        ddlDynamic.DataTextField = "catagory"
        ddlDynamic.DataValueField = "ID"
        ddlDynamic.DataBind()
        ddlDynamic.Items.Insert(0, "Select Catagory")

    End Sub

This is the method i have for creating the dropdown

Sub SubmitBtn_Excel(Sender As Object, E As EventArgs)
        Try
            Dim MyConnection As System.Data.OleDb.OleDbConnection
            Dim dataSet As System.Data.DataSet
            Dim MyCommand As System.Data.OleDb.OleDbDataAdapter
            Dim path As String = "C:\\Users\\John\\Documents\\John\\EPP\\WorldNet_Notes\\CHRISTIAN_BROTHERS_HIGH_SCHOOL.xlsx"

            MyConnection = New System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=Excel 12.0;")
            MyCommand = New System.Data.OleDb.OleDbDataAdapter("select * from [Sheet1$]", MyConnection)

            dataSet = New System.Data.DataSet
            MyCommand.Fill(dataSet)
            GridView1.DataSource = dataSet.Tables(0)

            MyConnection.Close()
        Catch ex As Exception

        End Try

    End Sub

This is the HTML

<form id="form1" runat="server" style="overflow-x:hidden; width:100%">
<div>
    <asp:button id="butOK" text="Add Dropdowns" onclick="SubmitBtn_Click" runat="server"/>
    <asp:button id="BtnAddExcel" text="Add Spreadsheet" OnClick="SubmitBtn_Excel" runat="server"/>
</div>
<div id ="ddlDynamic">
<!-- Dynamic Dropdowns -->

    <asp:GridView ID="GridView1" runat="server"></asp:GridView>
</div>
</form>

I am aware that this is all over the place, as you can see im a bit lost. I dont really want anybody to spoon fed me the answer, im just unsure how to structure it, or could anybody point me in the right direction to find out more. New to vb. Thanks in advance :-)