Find Data difference between DataSet and ASP.Net GridView using C# and VB.Net

Dear develpoers,

I am trying to find the differences between Imported Excel File and gridView data that imported from Oracle Database.

I am trying to put the data into DataSet, so I can compare between them. OracleDataImported v.s ImportedExcelFileData. OracleDataImported Code:

private static DataSet OracleDataImported()  
{  
    String strConnString;  
    strConnString = "DATA SOURCE=RCADEVC;USER ID=OUD;PASSWORD=123;";  
    var conn = new OracleConnection(strConnString);  
    String strSQL;  
  
    OracleCommand cmd = conn.CreateCommand();  
    strSQL = "select Name,Password from OUD.USERDATA";  
    cmd = new OracleCommand(strSQL, conn);  
    cmd.CommandType = CommandType.Text;  
  
    OracleDataAdapter da = new OracleDataAdapter();  
    da = new OracleDataAdapter(cmd);  
    DataSet ds1 = new DataSet();  
    da.Fill(ds1);  
  
    return ds1;  
}

ImportedExcelFileData code:

protected void ImportedExcelFileData(object sender, EventArgs e)  
{  
    // CHECK IF A FILE HAS BEEN SELECTED.  
    if ((FileUpload.HasFile))  
    {  
        if (!Convert.IsDBNull(FileUpload.PostedFile) &  
                FileUpload.PostedFile.ContentLength > 0)  
        {  
            // SAVE THE SELECTED FILE IN THE ROOT DIRECTORY.  
            FileUpload.SaveAs(Server.MapPath(".") + "\\" + FileUpload.FileName);  
  
            // SET A CONNECTION WITH THE EXCEL FILE.  
            OleDbConnection myExcelConn = new OleDbConnection  
                ("Provider=Microsoft.ACE.OLEDB.12.0; " +  
                    "Data Source=" + Server.MapPath(".") + "\\" + FileUpload.FileName +  
                    ";Extended Properties=Excel 12.0;");  
            try  
            {  
                myExcelConn.Open();  
  
                // GET DATA FROM EXCEL SHEET.  
  
                // READ THE DATA EXTRACTED FROM THE EXCEL FILE.  
                OleDbDataAdapter oleDbDataAdapter;  
                oleDbDataAdapter = new OleDbDataAdapter("select rtrim(ltrim(name)) as [Name],rtrim(ltrim(password)) as [Password] from [Sheet1$]", myExcelConn);  
                oleDbDataAdapter.TableMappings.Add("Table", "ExcelTable");  
                DataSet dataSet = new DataSet();  
                oleDbDataAdapter.Fill(dataSet);  
  
                // FINALLY, BIND THE EXTRACTED DATA TO THE GRIDVIEW.  
                DisplayExcelData.DataSource = dataSet;  
                DisplayExcelData.DataBind();  
  
                lblConfirm.Text = "DATA IMPORTED TO THE GRID, SUCCESSFULLY.";  
                lblConfirm.Attributes.Add("style", "color:green");  
            }  
            catch (Exception ex)  
            {  
                // SHOW ERROR MESSAGE, IF ANY.  
                lblConfirm.Text = ex.Message;  
                lblConfirm.Attributes.Add("style", "color:red");  
            }  
            finally  
            {  
                // CLEAR.  
                myExcelConn.Close(); myExcelConn = null;  
            }  
        }  
    }  
}

Button to find the differences code:

protected void calculate(object sender, EventArgs e)  
{  
    //Get data from UserData Table from DB  
    var ds = OracleDataImported();  
    //Assign the data to the first gridview  
    DisplayDBData.DataSource = ds;  
    DisplayDBData.DataBind();  
  
    DataSet dataSet;  
    //Get data from Excel data source and bind it to second gridview  
    var oleDbConnection = ImportedExcelFileData(out dataSet);  
    DisplayExcelData.DataSource = dataSet.Tables[0];  
    DisplayExcelData.DataBind();  
    oleDbConnection.Close();  
  
    //Find the difference of data and bind the data to third gridview  
    var dtAll = GetDataDifference(ds, dataSet);  
    DisplayDifferenceData.DataSource = dtAll;  
    DisplayDifferenceData.DataBind();  
}  

How to do it? Please, assist .. Regards,