ArrayList of a class

Question

3.67/5 (3 votes)

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I have the following snippets of code

C#

public class Project
{
    public int nPom;
    public string sName;
    public int nTotPom;
    public int nExtraTime;
    public bool bSelected;
}

when the user enters a name into a text box I do the following

C#

public partial class AddProjectForm : Form
{
  public AddProjectForm()
  {
      InitializeComponent();
  }

  private void btnOkay_Click(object sender, EventArgs e)
  {
      Project Projects = new Project();
      Projects.sName = txtProjectName.Text;
      this.Close();
  }
}

I want to make an ArrayList of Projects. What I have so far is this

C#

public static class ProjectGlobals
{
    ArrayList ProjectArray = new ArrayList();
}

Since Projects is not accessible to ProjectGlobals how would I go about doing this?

[edit]Code blocks moved to only cover code fragments - OriginalGriff[/edit]

Posted 23-Mar-11 21:30pm

CathyT

Updated 23-Mar-11 21:37pm

OriginalGriff

v3

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Comments

Toli Cuturicu 24-Mar-11 9:13am

For all of you! Stop using ArrayList! Think of them as deprecated for over 5 years! My God!

CathyT 24-Mar-11 22:18pm

If it's "deprecated" then why is it supported by .Net 4.0?!

2 solutions

Solution 1

I fixed many problems of your code in my Answer to your previous Question, why you repeat your mistakes?

OK. Don't use <code>ArrayList, it is obsolete, since generics were introduce. Use System.Collections.Generic.List<T> instead. Do you want all that problems with type casting?

Now, what's your problem with access modifiers. Make your list 1) a property (accessible field is a bad style), 2) make it internal (preferred) or public (only if you plan to access it from the other assembly).

—SA

Posted 23-Mar-11 21:43pm

Sergey Alexandrovich Kryukov

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OriginalGriff · Accepted Answer · 2011-03-23T21:51:00

Since you have declared Project as public it is available to all classes that can reference the assembly / namespace.

C#

public class Project
{
...
}

There is nothing stopping you from using it in ProjectGlobals

C#

public static class ProjectGlobals
{
    List<Project> ProjectArray = new List<Project>();
}

(Note that I have replaces ArrayList with the generic List<>: they are very, very similar, but a List<Project>will only hold projects, and you do not need to cast the contecnts when you use them)

Your problem is a bit more fundamental:

C#

private void btnOkay_Click(object sender, EventArgs e)
{
    Project Projects = new Project();
    Projects.sName = txtProjectName.Text;
    this.Close();
}

The method Creates an instance of a Project, and assigns a name to it. It then closes the form it is in. This makes doubly sure that the instance is discarded as it is out of scope!.

I assume that you are trying to set up a dialog to get a name for a new project?
If so, you could either:
1) Return the Project name via a property and let the calling form create the project and add it to it's list.
2) Return a completed Project via a property.
3) Mess about with a static as you are.

I would go with the first option: That way the same dialog can be re-used to change the name of a project.
The route you are taking is very messy, and there are much simpler ways to do it:

Main Form:

private List<Project> Projects = new List<Project>();
...
AddProjectForm apf = new AddProjectForm();
if (apf.ShowDialog() == DialogResult.OK)
   {
   Projects.Add(new Project(apf.ProjectName));
   }
...
   }

AddProjectForm:

public string ProjectName 
   { 
   get { return txtProjectName.Text; }
   set { txtProjectName.Text = value }
   }

You do not need the ProjectGlobals class at all.