Transfer Excel data into a SQL Server table using file upload - asp.net

Question

I need to give user a functionality of file upload where user can browse for a file and upload it to server. Data stored in the file will be extracted and inserted into a table.
Frontend code:
<asp:Panel ID="panelFileUpload" runat="server">
<table>
<tr>
<td><asp:Label ID="lblFileUpload" runat="server" Text="File Upload:"></asp:Label></td>
<td><asp:FileUpload CssClass = "FileUpload" ID="fuFileUpload" runat="server" />
<asp:Button ID="btnUploadFile" runat="server" CssClass="inputButton" OnClientClick="fnStartInterval()" Text="Upload" ValidationGroup="A" />
<asp:RequiredFieldValidator ID="RFValidator" runat="server" ControlToValidate="fuFileUpload" Font-Italic="True" Display="Dynamic" ValidationGroup="A">*Please choose a file to upload! </asp:RequiredFieldValidator>
</td>
</tr>
</table>
</asp:Panel>
I found this backend code for file upload but this is not working. My Excel file has 4 cols - col1...col4. I am not sure how to map the column of Excel to table structure.
Backend code:
Protected Sub btnUploadFile_Click(sender As Object, e As EventArgs) Handles btnUploadFile.Click
Dim filename As String = Path.GetFileName(fuFileUpload.PostedFile.FileName)
Dim contentType As String = fuFileUpload.PostedFile.ContentType
Using fs As Stream = fuFileUpload.PostedFile.InputStream
Using br As New BinaryReader(fs)
Dim bytes As Byte() = br.ReadBytes(CType(fs.Length, Integer))
Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
Using con As New SqlConnection(constr)
Dim query As String = "INSERT INTO dbo..table_1 VALUES (#ContentType, #Data)"
Using cmd As New SqlCommand(query)
cmd.Connection = con
cmd.Parameters.Add("#ContentType", SqlDbType.VarChar).Value = contentType
cmd.Parameters.Add("#Data", SqlDbType.Binary).Value = bytes
con.Open()
cmd.ExecuteNonQuery()
con.Close()
End Using
End Using
End Using
End Using
End Sub
Here, contenttype is being directly read from file. is there a way to read all 4 columns as it is and store it in table.

Answer 1

No promises on this but it should give you an idea on how this can be accomplished.
The DataTable is agnostic when it comes to its source so you can use the same DataTable for both the retrieved data from Excel and the insert data from to Sql Server.
Private Sub UpdateSQLServerFromExcel(FilePath As String)
Dim dt = New DataTable()
Using cnSource As New OleDbConnection($"Provider=Microsoft.ACE.OLEDB.12.0;Data Source={FilePath};Extended Properties=""Excel 12.0 Xml;HDR=YES"";")
Using selectCommand As New OleDbCommand("Select * From [Sheet1$];", cnSource)
Using da As New OleDbDataAdapter
'The following allows the .DataRowState to remain as Added (normally it is changed to Unchanged by the .Fill method)
da.AcceptChangesDuringFill = False
da.Fill(dt)
End Using
End Using
End Using
Using cnDestination As New SqlConnection("Your Sql Server connection string")
Using selectCommand As New SqlCommand("Select * From YourSqlTableName;", cnDestination)
Using da As New SqlDataAdapter()
da.SelectCommand = selectCommand
Dim cb As New SqlCommandBuilder(da)
da.Update(dt)
End Using
End Using
End Using
End Sub