Develop Reference

Struggling to add to ListBox

So I'm making this small program for my assignment at university and I'm finding it hard to add to my list in my form. Here is my code:
public partial class WorkOutBeam : Form
{
Check checkLib;
public BindingList<ListBox> list;
public WorkOutBeam()
{
InitializeComponent();
}
public void StartForm(object sender, EventArgs e)
{
list = new BindingList<ListBox>();
listBox1.DataSource = list;
}
private void NewForce_Click(object sender, EventArgs e)
{
NewForceName forceItem = new NewForceName();
forceItem.Show();
}
public void AddToForceList(string name)
{
list.Items.Add(name);
}
}
NewForceName class below:
public partial class NewForceName : Form
{
public WorkOutBeam workOutBeam;
public NewForceName()
{
InitializeComponent();
}
private void OkButton_Click(object sender, EventArgs e)
{
if (NewForceNames.Text != "")
{
ReferToLibs();
workOutBeam.AddToForceList(NewForceNames.Text);
Close();
}
}
private void ReferToLibs()
{
workOutBeam = new WorkOutBeam();
}
private void NewForceName_Load(object sender, EventArgs e)
{
}
}
So I say to my program, "give me a new force." When it does, it initializes a new form of "NewForceName." I type into a text box and click 'Ok', this starts a public method shown below:
The list is a binding list which refers to the listBox as a data source. However the program tells me that the Items part is inaccessible due to its protection but I don't know how to add it as public. I tried looking in the properties of my listBox but to no avail.

Give this a shot:
public partial class WorkOutBeam : Form
{
Check checkLib;
// public BindingList<ListBox> list; // get rid of this for now
public WorkOutBeam()
{
InitializeComponent();
}
/*public void StartForm(object sender, EventArgs e)
{
list = new BindingList<ListBox>();
listBox1.DataSource = list;
}*/
private void NewForce_Click(object sender, EventArgs e)
{
NewForceName forceItem = new NewForceName(this); // pass a reference to this
// instance of WorkoutBeam
forceItem.Show();
}
public void AddToForceList(string name)
{
// we should do some more things here, but let's keep it simple for now
listBox1.Items.Add(name);
}
}
And
public partial class NewForceName : Form
{
public WorkOutBeam workOutBeam;
public NewForceName( WorkoutBeam beam ) // we take a WorkoutBeam instance as CTOR param!
{
InitializeComponent();
workoutBeam = beam;
}
private void OkButton_Click(object sender, EventArgs e)
{
if (!string.IsNullOrEmpty(NewForceNames.Text))
{
workOutBeam.AddToForceList(NewForceNames.Text);
Close();
}
}
// DO NOT create new WorkoutBeams every time. Use the original.
/*private void ReferToLibs()
{
workOutBeam = new WorkOutBeam();
}*/
}
Disclaimer: I did not address each and every problem in this code. This is just enough so that it should "work" as intended.

how to call customized web form in asp.net

in windows application , when i want to call a customized form , i ueses this method :
result frm = new result();
frm.firstparameter = "first parameter";
frm.secondparameter = "second parameter";
frm.showdialog();
but in web application , i do not know how to handle it .
here is my webapplication source code :
in WebForm1.aspx.cs :
protected void sumbitbtn_Click(object sender, EventArgs e)
{
result frm = new result();
frm.firstparameter = "firstparameter";
frm.secondparameter = "secondparameter";
// frm.showpage() ???
// Response.Redirect("~/result.aspx");
}
in result.aspx.cs :
public partial class result : System.Web.UI.Page
{
private string Firstparameter = string.Empty;
public string firstparameter
{
get{return Firstparameter;}
set { Firstparameter = value; }
}
private string Secondtparameter = string.Empty;
public string secondparameter
{
get{return Secondparameter;}
set { Secondparameter = value; }
}
protected void Page_Load(object sender, EventArgs e)
{
firstlbl.Text=Firstparameter;
secondlbl.Text=Secondtparameter;
}
}

ASP.NET does not work that way. If you want to open one page after the other - you need to send a redirect request to do so. Of course you can also open popup, or make server transfer, but in your case redirect seems to be the best thing to do. Also note that parameters are not just passed into constructor or property - you need to attach them to the request, for example with query string.
So, in WebForm1.aspx.cs:
protected void sumbitbtn_Click(object sender, EventArgs e)
{
string url = string.Format("~/result.aspx?fp={0}&sp={1}", "firstparameter", "secondparameter");
Response.Redirect(url);
}
In result.aspx.cs :
public partial class result : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
firstlbl.Text = Request["fp"];
secondlbl.Text = Request["sp"];
}
}
Note that this code leaves a lot of things out (parameter null handling for one), it just shows the point.

Exchanging/Passing Values between C# forms

I have a problem with my code. Its working fine and there is no error but a logical one i think so. I have used a method PassValue(int id) to get value from another from. I have tested it and the forms are exchanging the values correctly but the problem comes when I use the value which i have received from other form as a "textbox.text" or a "label.text"
Here is my code:
namespace MyProgram
{
public partial class UserProfile : Form
{
public string empidstr;
public UserProfile()
{
InitializeComponent();
}
public void PassValue(int id)
{
string idstring = Convert.ToString(id);
// empidlabel.Text = idstring;
empidstr = idstring;
}
private void button2_Click(object sender, EventArgs e)
{
empidlabel.Text = empidstr;
}
private void UserProfile_Load(object sender, EventArgs e)
{
}
}}

using a listbox to display items from a class

My program compiles and to me it makes sense.
I want to know how to get 'name' to list in my listbox.
I'm trying to use an array of classes so I can add salesmen. A new class will be created every time a person is to be added.
This way the name is a way of calling all the data in that class.
When I execute the program everything looks like its doing what it's suppose to do but it just lists 'form1' in the list box when i press the list names button
This is what i mean:
Where am I going wrong?
SalesmanClass
namespace WindowsFormsApplication1
{
class SalesmanClass
{
private string name;
public string cNum;
public string Email;
public string address;
public string gArea;
public int tSales;
public string Name
{
get
{
return name;
}
set
{
name = value;
}
}
Form 1
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
Form2 w2;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
if (w2 == null)
{
w2 = new Form2();
w2.Show();
}
}
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
}
private void button2_Click(object sender, EventArgs e)
{
Object names;
names = Name;
listBox1.Items.Add(Name);
}
}
}
Form 2
//form2
namespace WindowsFormsApplication1
public partial class Form2 : Form
{
SalesmanClass[] salesman = new SalesmanClass[] { };
public Form2()
{
InitializeComponent();
}
private void Form2_Load(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
if (textBox1.Text.Trim().Length != 0)
{
for (int i = 0; i > salesman.Length; i++)
{
if (salesman[i] == null)
{
salesman[i].Name = textBox1.Text;
break;
}
}
this.Close();
}
else
{
MessageBox.Show("Please Input a Name");
}
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}
}
}

In this method:
private void button2_Click(object sender, EventArgs e)
{
Object names;
names = Name; // <--- Using this.Name, i.e. Form.Name, NOT SalesmanClass.Name
listBox1.Items.Add(Name);
}
You have accidentally used the Name property of the Form itself (which naturally is "form1").
You need to have a SalesmanClass object at this point, and use the Name property of that instead.
You don't currently have a list of salesmen in your Form1, so you will need to add one and use that.
Also, if you have a list or array of SalesmanClass objects, you should create a List<string> from them and use that to initialise the listbox, something like:
SalesmanClass[] salesmen = new SalesmanClass[] {};
// ...
List<string> names = new List<string>();
foreach (var salesman in salesmen)
names.Add(salesman.Name);
listBox1.Items.AddRange(names);
You can do this using Linq too, but I don't want to confuse you by introducing that into the mix!

In your button2_Click, you have :
names = Name;
What does this Name belong to ? I suspect it belongs to Form1, that's why it's been displaying "form1". If that's the case, you just need to get your SalesmanClass object and get the Name from it.

Passing a AVLTree between forms

There is another question that is very similar to mine however after reading it i still cannot get it to work.
I have two forms , MainForm and SecondForm and a few other classes, i need an instance of my AVLtree and be able to access it through my other forms.
This is what ive done so far
MainForm
public partial class MainForm : Form
{
AddArtist secondForm = new AddArtist();
public static AVLTree<Artist> treeAVL { get; set; }
public MainForm()
{
InitializeComponent();
}
private void butAdd_Click(object sender, EventArgs e)
{
secondForm.Show();
}
private void MainForm_Load(object sender, EventArgs e)
{
}
}
}
SecondForm
public partial class AddArtist : Form
{
String Name1 = "No Name";
int Members = 0;
public AVLTreetreeAVL = new AVLTree();
public AddArtist()
{
InitializeComponent();
treeAVL = MainForm.treeAVL;
}
private void MainForm_Load(object sender, EventArgs e)
{
}
private void butAdd_Click(object sender, EventArgs e)
{
Name1 = tBName.Text;
Members = (Convert.ToInt32(tBMem.Text));
Artist newArtist = new Artist(Name1,Members);
try
{
treeAVL.InsertItem(newArtist);
}
catch (Exception )
{
MessageBox.Show("No Data Entered", "Error",MessageBoxButtons.OK, MessageBoxIcon.Error);
}
tBName.Text = "";
tBMem.Text = " ";
}
}
}
Any help would be greatly appreciated pointing out where im going wrong or how to solve it.
It now compiles however it gives an error of Object reference not set to an instance of an object. i hope ive gone about coding this is the right way.

What is the access modifier of AVLTree class? Check if it is private or internal, since your code needs it to be public.

Set public on your parametrized type
public class Artist
{
..
}