Question

Code for Property in JobQuote class:

 public class JobQuote
{
// Properties
private List<string> _jobfilenames;
public List<string> JobFileNames
{
    get
    {
        if (_jobfilenames != null)
            return _jobfilenames;
        else
        {
            _jobfilenames = new List<string>();
            return _jobfilenames;
        }
    }

    set { _jobfilenames = value; }
}

Code for Property in User Control

public JobQuote quote
{
    get 
    {
        if (ViewState["Quote"] != null)
            return (JobQuote)ViewState["Quote"];
        else
        {
            JobQuote newQuote = new JobQuote();
            return newQuote;
        }   
    }
    set { ViewState["Quote"] = value; }
}

Code in try block of UserControl where the string is not being added to the generic list of strings:

try
        {
            string filename = System.IO.Path.GetFileName(FileUploader.FileName);
            quote.JobFileNames.Add(filename); 
        }     

What am I doing wrong?

Answer 1

You are reading from the viewstate but you never assign.

public JobQuote quote 
{ 
    get  
    { 
        if (ViewState["Quote"] != null) 
            return (JobQuote)ViewState["Quote"]; 
        else 
        { 
            // you only construct a new instance but you dont assign it to the viewstate
            JobQuote newQuote = new JobQuote(); 
            // add the following line to fix the problem
            // ViewState["Quote"] = newQuote;
            return newQuote; 
        }    
    } 

This means that next time you refer to the quote property, a new JobQuote instance will be created rather than your old JobQuote instance being returned

A clean way for implementing this would be:

public JobQuote Quote
{
    get
    {
        JobQuote result = ViewState["Quote"] as JobQuote;
        if (result == null)
        {
            result = new JobQuote();
            ViewState["Quote"] = result;
        }

        return result;
    }
}