Develop Reference

How do I set event methods for programmatically created combo boxes?

I am creating small program that has dynamically created combo boxes. Each time the user opens the program, based on some context, there could be 3-30 items that need 4 drop down lists for selection. I am creating these based off of the following code, which is just a snippet.
for (int i = 0; i < 4; i++)
{
s.Children.Add(new ComboBox()
{
VerticalAlignment = VerticalAlignment.Top,
HorizontalAlignment = HorizontalAlignment.Left,
Margin = new Thickness(m, -25, 0, 0),
Width = 75,
Height = 25,
FontSize = 12,
Name = "obj1_" + i.ToString(),
ItemsSource = objs,
});
m = m + 50;
s.Children.Add(new Label()
{
VerticalAlignment = VerticalAlignment.Top,
HorizontalAlignment = HorizontalAlignment.Left,
Margin = new Thickness(m, -25, 0, 0),
Width = 25,
Height = 25,
FontSize = 12,
Name = "lbl1_" + i.ToString(),
});
}
s is a stack panel that I am adding each of the combo boxes too. The ItemSource is from a small method elsewhere to figure out which list should go into the drop down.
My question is, how do I call the events for these created combo boxes? Trying
private void obj1_1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ComboBox this_box = (ComboBox)sender;
lbl1_1.Content = "!!!";
}
works well enough but the label doesn't exist in the current context.
Also, am I creating the boxes and labels the best way for this type of scenario?
Thanks in advance.

Inside you for loop
1)Create an new Panel
2)Add the label and combo to that panel
3)Add the newly created panel to s
Inside your obj1_1_SelectionChanged event:
1)Find the Parent control of the ComboBox
2)Search for the label inside its Children and update its text
Solution 2
When you create your controls create a Guid (or an int) and set the Tag property of your controls to that object.
Now when you are on a combo you can search your Window for the label with the same Tag
for (int i = 0; i < 4; i++)
{
Guid g = Guid.NewGuid();
s.Children.Add(new ComboBox()
{
Tag = g
});
s.Children.Add(new Label()
{
Tag = g
});
}

c# objects won't go under each other

i'm making a simple login-register program, i save usernames and passwords in lists.
i'm trying to show all the usernames under each other and that it wil repeat everytime a new user will be registered.
for some reason it only shows the last user, and that's it.
for (Int32 i = 0; i < frmLogin.reg_usernames.Count; i++ )
{
TextBox lbl = new TextBox { Location = new Point(15, 30), BorderStyle = BorderStyle.Fixed3D, BackColor = Color.AliceBlue, Font = new Font(Font.FontFamily.Name, 9), ScrollBars = ScrollBars.Vertical };
this.Controls.Add(lbl);
lbl.Text = frmLogin.reg_usernames[i];
}

You need to move the boxes down as you go:
TextBox lbl = new TextBox { Location = new Point(15, 30 * i), BorderStyle ....
Note that your form would need to be large enough to see them all, as well. You may need to set your height appropriately, or place the text boxes inside of a container which could scroll, instead of directly on the form itself.

Add Controls to GroupBox which was created dynamically

I add GroupBoxes to an ItemsControl dynamically using:
string name_ = "TestName", header_ = "TestHeader"
GroupBox MyGroupBox = new GroupBox { Name = name_, Header= header_, Width = 240, Height = 150, Foreground=new SolidColorBrush(Color.FromArgb(255, 0, 0, 0)) };
MyItemsControl.Items.Add(MyGroupBox);
Now I need to add content to this GroupBox, like a few TextBlocks created like:
TextBlock MyTextBlock = new TextBlock {Text = "test"};
But I can't figure out how to do that. Normally to a Grid or something like that I would just use .Children.Add(MyTextBlock), but that doesn't work here.
Also I have to be able to remove specific Items from the ItemsControl again (best would be by the name of the Item, name_ in this example).

Try something like that
GroupBox groupBox1 = new GroupBox();
Grid grid1 = new Grid();
TextBlock MyTextBlock = new TextBlock {Text = "test"};
groupBox1.Width = 185;
groupBox1.Height = 160;
grid1.Height = 185;
grid1.Width = 160;
grid1.Children.Add(MyTextBlock);
groupBox1.Content = grid1;
mainWindow.canvas.Children.Add(groupBox1);

The GroupBox has only a Content Property which is designed to hold a ContentPresentor. You can add a Grid/Canvas etc.. to the GroupBox and then add your content to that.

Adding controls to GroupBox during runtime

I'm trying to create a GroupBox, add a Grid (or StackPanel) to it then put some TextBlocks on it, all during runtime. This is what i've tried
GroupBox groupBox1 = new GroupBox();
Grid grid1 = new Grid();
groupBox1.Width = 85;
groupBox1.Height = 60;
grid1.Height = 85;
grid1.Width = 60;
groupBox1.Content = grid1.Children.Add(textBlock1);
groupBox1.Margin = new Thickness(50, 50, 0, 0);
mainWindow.canvas.Children.Add(groupBox1);
But all I get is a groupbox with a thick white border with nothing in it.

As far as I can see a Grid.Children.Add returns an int and that's not what you want to set the content of the groupBox1 to.
An untested idea from me as a non WPF expert is to set the grid as the Content of your groupbox.
grid1.Children.Add(textBlock1);
groupBox1.Content = grid1;

For simple checkboxes i used this code :
var container = new FlowLayoutPanel
{
FlowDirection = FlowDirection.TopDown,
Dock = DockStyle.Fill
};
myGroupBox.Controls.Add(container);
foreach (var myText in textList)
{
var checkBox = new CheckBox
{
Text = myText
};
container.Controls.Add(checkBox);
}
Of course the foreach statement is just for the example :)

setting DockStyle.Fill for dynamic controls does not resize when i move the splitter

I have a split container on panel 1 I have added a groupbox, in that groupbox is a flowcontrol which has dynamic number of textboxes, i have set both the groupbox and flowcontrol to dockstyle to fill.
In code i have also set the textboxes to dock style to fill, but they wont resize when i move the splitter, while the parent flowcontrol does resize.
Label labelInput = new Label();
TextBox listBoxNewInput = new TextBox();
listBoxNewInput.Name = ce.ToString();
labelInput.AutoSize = true;
labelInput.Font = new Font(labelInput.Font, FontStyle.Bold);
listBoxNewInput.Multiline = true;
// Add vertical scroll bars to the TextBox control.
listBoxNewInput.ScrollBars = ScrollBars.Vertical;
// Allow the RETURN key in the TextBox control.
listBoxNewInput.AcceptsReturn = true;
// Allow the TAB key to be entered in the TextBox control.
listBoxNewInput.AcceptsTab = true;
// Set WordWrap to true to allow text to wrap to the next line.
listBoxNewInput.WordWrap = true;
listBoxNewInput.Text = ts.ToString();
//listBoxNewInput.Width = 150;
listBoxNewInput.MinimumSize = new Size(200,150);
listBoxNewInput.MaximumSize = new Size(1000, 150);
listBoxNewInput.Dock = DockStyle.Fill;
listBoxNewInput.TextChanged += new EventHandler(listBoxNewInput_TextChanged);
//Add the newly created text box to the list of input text boxes
inputTextBoxesList.Add(listBoxNewInput);
//Add the labels and text box to the form
flowLayoutPanel1.Controls.Add(labelInput);
flowLayoutPanel1.Controls.Add(listBoxNewInput);
if i try to put controls directly in to spliter panel 1 only the first two controls appear, which do resize when i move the splitter
splitContainer1.Panel1.Controls.Add(labelInput); splitContainer1.Panel1.Controls.Add(listBoxNewInput);
->if the controls when i put them in flow control resize, when i move the splitter that would be good
OR
->All controls appear when i put them directly into the splitter panel 1

Based on your comments and what I think you are trying to accomplish, I think you need to replace the FlowLayoutPanel with a TableLayoutPanel because it sounds like you are just stacking one TextBox below another.
Create a TableLayoutPanel with 1 column and 1 row.
Here is a working example:
tableLayoutPanel1.AutoScroll = true;
tableLayoutPanel1.GrowStyle = TableLayoutPanelGrowStyle.AddRows;
tableLayoutPanel1.RowStyles.Clear();
tableLayoutPanel1.RowStyles.Add(new RowStyle(SizeType.Absolute, 150));
for (int i = 0; i < 4; i++) {
AddTextBox("TextBox #" + i.ToString());
}
private void AddTextBox(string info) {
TextBox tx = new TextBox();
tx.Multiline = true;
tx.Text = info;
tx.ScrollBars = ScrollBars.Vertical;
tx.WordWrap = true;
tx.Height = 150;
tx.Anchor = AnchorStyles.Left | AnchorStyles.Top | AnchorStyles.Right;
tableLayoutPanel1.Controls.Add(tx);
}
Instead of docking, I set the height of the TextBox and then I set the Anchors so that when the SplitPanel resizes, the TextBoxes resize appropriately.