Want to protect your cyber security and still get fast solutions? Ask a secure question today.Go Premium

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 250
  • Last Modified:

Dynamic list creation

Greetings all

I have a method that returns the results of stored procedure, selected by the user. I would like to return that data to the UI layer via a generic list. The problem is that I have no way of knowing how many fields or what type comes back.

Is this possible using a List/Class in a similiar way to the attached snippet (this is just an example of a simple case) ??


In advance, thanks!!!

    allanamrk
SAMPLE CLASS
 
List<EMailAddress> emailContacts = new List<EMailAddress>();
 
using System;
using System.Collections.Generic;
using System.Text;
 
namespace DataTransferObjects
{
    public class EMailAddress
    {
 
        private string name;
        private string email;
        
        public EMailAddress()
        {
 
        }
 
        public EMailAddress(string pName, string pEmail)
        {
            name = pName;
            email = pEmail;
        }
 
        public string Name
        {
            get { return name; }
            set { name = value; }
        }
 
        public string Email
        {
            get { return email; }
            set { email = value; }
        }
 
    }
}

Open in new window

0
allanmark
Asked:
allanmark
  • 6
  • 6
1 Solution
 
DabasCommented:
What about returning a list of DataRows?

List<DataRow> MyDataRowList = new List<DataRow>();

Dabas
0
 
allanmarkAuthor Commented:
I tried that, but I need to work with the data in a GridView. When I linked the List (of DataRow) to the grid, it complained that there was no DATAFIELD - what I had was a list of array.
0
 
DabasCommented:
Show me the code where you bind to the grid
0
Free Backup Tool for VMware and Hyper-V

Restore full virtual machine or individual guest files from 19 common file systems directly from the backup file. Schedule VM backups with PowerShell scripts. Set desired time, lean back and let the script to notify you via email upon completion.  

 
allanmarkAuthor Commented:
queryResults =
    BusinessLogic.Business.GetQueryResults(.......);

// Binding
gvResults.DataSource = queryResults;
 gvResults.DataBind();
0
 
DabasCommented:
And the code for GetQueryResults?
0
 
allanmarkAuthor Commented:
Ooops!!!

Sorry!  I'm having a really blonde day!! (no offense intended, if you happen to be blonde!!!).


 public static List<DataRow> GetQueryResults(string procName, List<DbParam> dbParms, string [] fieldNames)
        {
            List<DataRow> queryResults = new List<DataRow>();
 
            queryResults = DataAccess.ReturnQueryResults(procName, dbParms);
 
            return queryResults;
        }
 
 
public static List<DataRow> ReturnQueryResults(string procName, List<DbParam> dbParms)
{
            List<DataRow> returnedRecords = new List<DataRow>();
                        
            SqlParameter workParam;
 
            SqlConnection sqlConn = new SqlConnection(connectStr);
 
            DataSet dsQuery = new DataSet();
                   
            SqlDataAdapter daQuery = new SqlDataAdapter(procName, sqlConn);
            daQuery.SelectCommand.CommandType = CommandType.StoredProcedure;
 
            if (dbParms.Count > 0)
            {
                foreach (DbParam parm in dbParms)
                {
                    workParam = GetParameter(parm.ParmName, parm.ParmType, parm.ParmVal);
                    daQuery.SelectCommand.Parameters.Add(workParam);
                }
            }
         
            daQuery.Fill(dsQuery, "QueryResults");
 
            List <DataRow> returnedRecords = new List<DataRow>(dsQuery.Tables["QueryResults"].Select());
 
            return returnedRecords;
}

Open in new window

0
 
DabasCommented:
Thanks

I suggest that you try filling a DataTable instead of a DataSet
Then instead of returning a List of rows, return the DataTable.

DataGridViews work very well with DataTables

Dabas
0
 
allanmarkAuthor Commented:
COuld do that.
It's just that we have been encouraged to work with Lists, so as to achieve independance/separattion between the DataLayer and the UI and also to n=minimise reliance on System.Data.

0
 
DabasCommented:
It could be the right approach, except for your statement 'The problem is that I have no way of knowing how many fields or what type comes back'

I do not see anything wrong with reliance on System.Data. The same can be argued against reliance on System.Collections.

Dabas
0
 
allanmarkAuthor Commented:
Ok.

So maybe what I need to do is work with the lists, where I have a definite structure that is returned and where it is something flexible / unknown (shoudl only be this one case) return a datatable.

Does that sound like an acceptable "work-around" compromsie, to you?
0
 
DabasCommented:
Yes
0
 
allanmarkAuthor Commented:
Many thanks!!!
0

Featured Post

VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

  • 6
  • 6
Tackle projects and never again get stuck behind a technical roadblock.
Join Now