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How to populate over multiple columns?

I am working on an 'attendance' system for the school I work at. I'm using a listview for this, but noticed that there's simply not enough space to house all employees in one list. So I want to add a second column (or at least, another 'instance' of the three columns currently used). How do I manage to get such job done?
I have been thinking about workarounds such as a second listview instance, but that would make things only more complex in my opinion. So I'd like to stick by one.
See image below for visual description of what I want to get; I want the output to first fill the left part of the listview, then the right one.
And this is the part of my code that it's (probably) about:
public void LoadEmployees()
{
lvEmployees.View = View.Details;
lvEmployees.GridLines = true;
lvEmployees.Items.Clear();
List<Employees> data = database.LoadEmployees();
for (int i = 0; i < data.Count; i++)
{
// Define the list items
ListViewItem emp = new ListViewItem(data[i].Abbreviation);
emp.SubItems.Add(data[i].Name);
emp.SubItems.Add(data[i].Status);
// Add the list items to the ListView
lvEmployees.Items.Add(emp);
}
}

With lvEmployees1 and lvEmployees2 (or left/right), two ListView.
We can simply split the List<Employees> data in half.
lvEmployees1.View = View.Details;
lvEmployees1.GridLines = true;
lvEmployees1.Items.Clear();
lvEmployees2.View = View.Details;
lvEmployees2.GridLines = true;
lvEmployees2.Items.Clear();
List<Employees> data = database.LoadEmployees();
int half = data.Count / 2;
for (int i = 0; i < data.Count; i++)
{
// Define the list items
ListViewItem emp = new ListViewItem(data[i].Abbreviation);
emp.SubItems.Add(data[i].Name);
emp.SubItems.Add(data[i].Status);
if (i <= half) lvEmployees1.Items.Add(emp);
else lvEmployees2.Items.Add(emp);
}
To create the second "grid", you can simply copy past the element in the designer.

Clearing button Array

I am creating a grid of buttons using the following code:
Button[][] buttons;
In the method:
for (int r = 0; r < row; r++)
{
for ( int c = 0; c < col; c++)
{
buttons[r][c] = new Button();
}
}
How can I clear and reset buttons[][] if row or col changes, is there away to do it?

Yes, there is. You can call the Array.Clear() function. Since your array holds Button objects, which are reference types, it will reset every item in the array to null.
Array.Clear(buttons, 0, buttons.Length);
However, I strongly suggest using one of the generic containers for this, rather than a raw array. For example, a List<T> would be a good choice. In your case, T would be Button.
using System.Collections.Generic; // required at the top of the file for List<T>
List<Button> buttons = new List<Button>();
To use it like a two-dimensional array, you will need a nested list (basically, a List that contains a List that contains Button objects). The syntax is a little intimidating, but it's not so hard to figure out what it means:
List<List<Button>> buttons = new List<List<Button>>();

you can invoke Clear() Method
http://msdn.microsoft.com/en-us/library/system.array.clear.aspx

how to define an array of textboxes in c#?

Hi when I create textboxes on Windows Application Form I cannot name it as box[0], box[1] and so on. The purpose why I want to do like this is because I want to use them in a loop.

Actually I found TextBox[] array = { firstTextBox, secondTextBox }; works too!

How about making a list of them after you create them? In your form initialization function, you can do something like:
List<TextBox> myTextboxList = new List<TextBox>();
myTextBoxList.Add(TextBox1);
myTextBoxList.Add(TextBox2);
mytextBoxList.Add(TextBox3);
Now you can itterate through with your "myTextboxList" with something like below:
Foreach (TextBox singleItem in myTextboxList) {
// Do something to your textboxes here, for example:
singleItem.Text = "Type in Entry Here";
}

You can create textboxes on runtime and just put them in an array...
If you want to do it in design time, you will have to do some control filtering logic on the whole this.Controls array in order to access only the wanted textboxes. Consider if (currControl is TextBox) if all textboxes in the form are ones you want in the array.
Another option for design time, is putting all wanted textboxes in a panel which will be their parent, and then iterating over the panel's children (controls) and cast them to TextBox.
A runtime solution would be something like:
var arr = new TextBox[10];
for (var i = 0; i < 10; i++)
{
var tbox = new TextBox();
// tbox.Text = i.ToString();
// Other properties sets for tbox
this.Controls.Add(tbox);
arr[i] = tbox;
}

I wouldn't use an array for this, personally. I would use some form of generic collection, like List.
List<TextBox> textBoxList = new List<TextBox>();
//Example insert method
public void InsertTextBox(TextBox tb)
{
textBoxList.Add(tb);
}
//Example contains method
public bool CheckIfTextBoxExists(TextBox tb)
{
if (textBoxList.Contains(tb))
return true;
else
return false;
}
You don't necessarily have to use the Contains method, you could also use Any(), or maybe even find another way- all depends on what you're doing. I just think using a generic collection gives you more flexibility than a simple array in this case.

for C# just use this to create an array of text boxes
public Text [] "YourName" = new Text ["how long you want the array"];
then add the text boxes to the array individually.

TextBox Array using C#
// Declaring array of TextBox
private System.Windows.Forms.TextBox[] txtArray;
private void AddControls(int cNumber)
{
// assign number of controls
txtArray = new System.Windows.Forms.TextBox[cNumber + 1];
for (int i = 0; i < cNumber + 1; i++)
{
// Initialize one variable
txtArray[i] = new System.Windows.Forms.TextBox();
}
}

TextBox[] t = new TextBox[10];
for(int i=0;i<required;i++)
{
t[i]=new TextBox();
this.Controls.Add(t[]);
}

Highlight a C# ListView row

I'm using a ListView in Details mode to display a list. I want to change the current index in two ways: firstly, by a mouse click (which works now), and secondly with + and - buttons. The problem is that when I click the button, the list loses focus and the row highlight disappears. How do I keep the highlight?
EDIT: Okay, I found the HideSelection property. But how do I change the selected index from the outside?

You can do something simple like this
this.listView1.Items[0].Selected = true;
Or you can iterate throught the list of items and find the one that you want to select.
private void PlusButtonClick()
{
int newIndex = 0;
for (int x = 0; x < listView1.Items.Count; x++)
{
if(listItem.Selected);
{
listItem.Selected = false;
newIndex = x++;
break;
}
}
this.listView1.Items[newIndex].Selected = true;
}

Dynamic Variable Name Use in C# for WinForms

Not sure what is the best way to word this, but I am wondering if a dynamic variable name access can be done in C# (3.5).
Here is the code I am currently looking to "smarten up" or make more elegant with a loop.
private void frmFilter_Load(object sender, EventArgs e)
{
chkCategory1.Text = categories[0];
chkCategory2.Text = categories[1];
chkCategory3.Text = categories[2];
chkCategory4.Text = categories[3];
chkCategory5.Text = categories[4];
chkCategory6.Text = categories[5];
chkCategory7.Text = categories[6];
chkCategory8.Text = categories[7];
chkCategory9.Text = categories[8];
chkCategory10.Text = categories[9];
chkCategory11.Text = categories[10];
chkCategory12.Text = categories[11];
}
Is there a way to do something like ("chkCategory" + i.ToString()).Text?

Yes, you can use
Control c = this.Controls.Find("chkCategory" + i.ToString(), true).Single();
(c as textBox).Text = ...;
Add some errorchecking and wrap it in a nice (extension) method.
Edit: It returns Control[] so either a [0] or a .Single() are needed at the end. Added.

for(...)
{
CheckBox c = this.Controls["chkCategory" + i.ToString()] as CheckBox ;
c.Text = categories[i];
}

You can do that with reflection. But don't.
It's more proper to instantiate a list of contols, add them programmatically to your form, and index that.

Sometimes it can help to put your controls into an array or collection as such:
Checkbox[] chkCataegories = new Checkbox[] { chkCategory1, chkCategory2 ... };
for(int i = 0; i < chkCategories.Length; i++)
chkCategories[i].Text = categories[i];
As another approach, you can dynamically create your checkboxes at runtime instead of design time:
for(int i = 0; i < categories.Length; i++)
{
Checkbox chkCategory = new chkCategory { Text = categories[i] };
someContainer.Controls.Add(chkCategory);
}
At least with dynamically created controls, you don't need to modify your GUI or your form code whenever you add new categories.

You don't need dynamic for that. Put chkCategory1 - 12 in an array, and loop through it with a for loop. I would suggest you keep it around in a field and initialize it at form construction time, because chkCategory seems to be related. But if you want a simple example of how to do it in that simple method, then it would be something like this:
private void frmFilter_Load(object sender, EventArgs e)
{
var chkCategories = new [] { chkCategory1, chkCategory2, chkCategory3, .......... };
for(int i = 0 ; i < chkCategories.Length ; i++ )
chkCategoies[i].Text = categories[i];
}
You know more about the application, so you could perhaps avoid writing out all the control names - for instance, if they are placed on a common parent control, then you could find them by going through it's children.

No, but you could do something like this (untested, beware of syntax errors):
private readonly CheckBox[] allMyCheckboxes = new CheckBox[] { chkCategory1, chkCategory2, ... }
Then you just need to do
for (i = 0; i < 12; i++) allMyCheckboxes[i].Text = categories[i];

The "this.Controls["chkCategory" + i.ToString()]" and "this.Controls.Find("chkCategory" + i.ToString(), true)" both do not work... the former informs you that the contents of the [] are not an int and the latter that ControlCollection does not contain a definition for Find.
Use "Control myControl1 = FindControl("TextBox2");" instead.
I needed this form as I was looping through another array, extracting values and using them to populate form fields. Much easier to look for label1, label2, label3, etc.