Question

I am retrieving 4 Fields from my database table. Now i want to add them to a dynamic list <>. How to add those into the list.
I tried this :

public class myclass
{
   public string StdDetails, StdAdderID;
   public DateTime StdAddedDate, StdAddedTime;
}

public void buttonClick()
{
    List<myclass> StdList = new List<myclass>();

    myclass mc = new myclass();

    OdbcCommand readStd = 
        new OdbcCommand("SELECT StdDetails, StdAddedDate," +
                        "StdAddedTime, StdAdderID" +
                        "FROM Students", Conn);

    OdbcDataReader readStdreader = 
        readStd.ExecuteReader(CommandBehavior.SingleRow);

    while (readStdreader .Read())
    {
        mc.StdDetails = readStdreader.GetString(0);
        mc.StdDetails = readStdreader.GetString(3); 
        mc.StdDetails = readStdreader.GetDate(1);
        mc.StdDetails = readStdreader.GetDateTime(2);
        StdList.Add(mc);
    }
    MessageBox.Show(StdList[0].ToString());
}

In the message box the value isn’t displayed? what to do.please help

//SORRY FOR THE TYPOS :

replace these 3 lines :

mc.StdDetails = readStdreader.GetString(3); 
        mc.StdDetails = readStdreader.GetDate(1);
        mc.StdDetails = readStdreader.GetDateTime(2);

with :

mc.StdAddedDate= readStdreader.GetString(3); 
                mc.StdAdderID= readStdreader.GetDate(1);
                mc.StdAddedTime= readStdreader.GetDateTime(2);

Answer 1

You’re only creating a single instance of myclass, so your list will be full of references to the same object. You want this instead:

while (readStdreader.Read())
{
    myclass mc = new myclass();
    mc.StdDetails = readStdreader.GetString(0);
    mc.StdAdderID = readStdreader.GetString(3);
    mc.StdAddedDate= readStdreader.GetDate(1);
    mc.StdAddedTime = readStdreader.GetDateTime(2);
    StdList.Add(mc);
}

Note how I’ve changed the properties that are assigned, too – the code you posted attempts to assign to StdDetails repeatedly.

You also haven’t overridden ToString in myclass, so calling ToString() isn’t going to give you anything particularly useful.

Additionally:

• You should look into the .NET naming conventions; your naming is all over the shop at the moment. (What does std mean here? You’ve used it for almost everything…)
• Public fields are a really bad idea; use properties instead
• Use using statements to close readers, commands, connections etc in a reliable way.