Removing dynamic controls from panel

Question 1

You are still not saying which control you want to remove, what type of controls you want to remove or how you want to identify them.

You could just loop through the controls to remove specific Controls.

If you have Linq, its easy:

private void btn_Click(object sender, EventArgs e)
{
    panel1.Controls.Clear(); //to remove all controls


    //to remove all comboboxes
    foreach (Control item in panel1.Controls.OfType<ComboBox>().ToList())
    {
        panel1.Controls.Remove(item); 
    }


   //to remove control by Name
    foreach (Control item in panel1.Controls.OfType<Control>().ToList())
    {
        if (item.Name == "bloodyControl")
            panel1.Controls.Remove(item); 
    }

    
    //to remove just one control, no Linq
    foreach (Control item in panel1.Controls)
    {
        if (item.Name == "bloodyControl")
        {
             panel1.Controls.Remove(item);
             break; //important step
        }
    }
}

Edit:

Its easy to do the same since you're tagging the control already. All you need is to just retrieve the control back from tag. But you need to tag appropriately:

Do this instead:

private void button1_Click(object sender, EventArgs e)
{
    int v;
    v = c++;
    panel1.VerticalScroll.Value = VerticalScroll.Minimum;

    Button btn = new Button();
    btn.Name = "btn" + v;
    btn.Text = "Remove";
    btn.Location = new Point(750, 5 + (30 * v));
    btn.Click += new EventHandler(btn_Click);
    
    ComboBox combo = new ComboBox();
    combo.Name = "combobox" + v ;
    combo.Location = new Point(30, 5 + (30 * v));
    combo.Tag = btn;

    ComboBox combo2 = new ComboBox();
    combo2.Name = "combobox2" + v ;
    combo2.Location = new Point(170, 5 + (30 * v));
    combo2.Tag = btn;

    TextBox txt = new TextBox();
    txt.Name = "txtbx" + v;
    txt.Location = new Point(300, 5 + (30 * v));
    txt.Tag = btn;

    TextBox txt2 = new TextBox();
    txt2.Name = "txtbx2" + v;
    txt2.Location = new Point(450, 5 + (30 * v));
    txt2.Tag = btn;

    TextBox txt3 = new TextBox();
    txt3.Name = "txtbx3" + v;
    txt3.Location = new Point(600, 5 + (30 * v));
    txt3.Tag = btn;

    panel1.Controls.Add(combo);
    panel1.Controls.Add(btn);
    panel1.Controls.Add(txt);
    panel1.Controls.Add(combo2);
    panel1.Controls.Add(txt2);
    panel1.Controls.Add(txt3);    
}

private void btn_Click(object sender, EventArgs e)
{
   //to remove control by Name
    foreach (Control item in panel1.Controls.OfType<Control>().ToList())
    {
        if (item.Tag == sender || item == sender)
            panel1.Controls.Remove(item); 
    }
}

Here you are tagging controls with the button, hence on the button click you can remove all the controls whose tags are the clicked button which you get from sender argument. But the downside of this approach is that you have to enumerate all the controls of the panel which is not great.

Edit: As I came to learn the below code is for a table layout panel which the OP isn't using for now. But anyway a table panel layout is better suited for this job.

I would suggest you to do this:

private void button1_Click(object sender, EventArgs e)
{
    int v;
    v = c++;
    panel1.VerticalScroll.Value = VerticalScroll.Minimum;

    Button btn = new Button();
    btn.Name = "btn" + v;
    btn.Text = "Remove";
    btn.Location = new Point(750, 5 + (30 * v));
    btn.Click += new EventHandler(btn_Click);
    btn.Tag = v;

    ComboBox combo = new ComboBox();
    combo.Name = "combobox" + v ;
    combo.Location = new Point(30, 5 + (30 * v));
    combo.Tag = v;

    ComboBox combo2 = new ComboBox();
    combo2.Name = "combobox2" + v ;
    combo2.Location = new Point(170, 5 + (30 * v));
    combo2.Tag = v;

    TextBox txt = new TextBox();
    txt.Name = "txtbx" + v;
    txt.Location = new Point(300, 5 + (30 * v));
    txt.Tag = v;

    TextBox txt2 = new TextBox();
    txt2.Name = "txtbx2" + v;
    txt2.Location = new Point(450, 5 + (30 * v));
    txt2.Tag = v;

    TextBox txt3 = new TextBox();
    txt3.Name = "txtbx3" + v;
    txt3.Location = new Point(600, 5 + (30 * v));
    txt3.Tag = v;

    panel1.Controls.Add(combo);
    panel1.Controls.Add(btn);
    panel1.Controls.Add(txt);
    panel1.Controls.Add(combo2);
    panel1.Controls.Add(txt2);
    panel1.Controls.Add(txt3);    
}

private void btn_Click(object sender, EventArgs e)
{
    int toBeDeletedRow = (int)((Control)sender).Tag;
    for (int row = panel1.RowCount - 1; row >= 0; row--)
    {
        if (row == toBeDeletedRow)
        {
            panel1.RowStyles.RemoveAt(row);
            panel1.RowCount--;
            return;
        }
    }
}

Question 2

If you have a Panel o other container with more dinamicaly components for remove all or more than one you can proceed in this way.

In first step you load a component in array or list.

List<PersonalUserControl> lst = new List<PersonalUserControl>();

foreach (Object obj in this.PanelImplementationTeam.Controls)
{     
    //DO NOT REMOVE COMPONENT IN THIS LOOP BECAUSE
    //YOU DECREASE THE .Controls  ARRAY AND YOU WILL HAVE AN ERROR      
    if (obj is PersonalUserControl)
    {
        lst.Add((PersonalUserControl)obj);
    }
}

foreach(PersonalUserControl uc in lst)
{
    uc.Dispose();
}

Question 3

If all of your controls that you want to delete are in a Panel, you can do: panel.Controls.Clear(); That clears all controls form your panel.

Question 4

Remove control events. From MSDN:

To remove controls from a collection programmatically

Remove the event handler from the event. In Visual Basic, use the RemoveHandler Statement keyword; in Visual C#, use the -= Operator (C# Reference).

Use the Remove method to delete the desired control from the panel's Controls collection.

Call the Dispose method to release all the resources used by the control.

Specific examples are given using VB and C# in the linked page.

Question 5

Since the controls are added at the run time, register them before using the findName method using the register method.

StackPanel sp = new StackPanel
{
   Name = "mySP",
   Orientation = Orientation.Horizontal,
};

//need to register the control to find it by name
RegisterName(sp.Name, sp);

//now to find control by name 
StackPanel sp = (StackPanel)mainStackPanel.FindName("mySP");

//deleting the control found
mainStackPanel.Children.Remove(sp);

//if you need to use the same name again, you have to unregister too
UnregisterName(sp.Name);