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Location of panel not correct when using different anchor style

this is for Winforms / C# btw.
So I am making my own ComboBox, just playing around.
The item List is basically a Panel, which is located under or above the ComboBox control, depending on its height and location.
This works as intended, as long as I use AnchorStyle Top / Left for my usercontrol.
As soon as I switch to Top / Right Style, the location of my listpanel breaks. Okay, makes sense, the location point of my usercontrol changes with the different anchorstyle, so how about I adjust my panel to a new location using my usercontrol.LocationChanged event? Doesen't work. Maybe because of the order of the events? Or does the origin of locations change depending on the given AnchorStyles?
Anyway, I am a bit lost. Unfortunately I couldn't find a similar case here, therefore this question.
Here's my DropDownPanel (effectively my "list"):
private Panel DropDownPanel()
{
Panel DropDownPanel = new Panel() {
Width = this.Width,
Height = 200,
BackColor = _skin.TextBoxBackColor,
BorderStyle = BorderStyle.FixedSingle,
ForeColor = _skin.TextBoxForeColor,
Visible = false,
AutoScroll = false
};
DropDownPanel.HorizontalScroll.Enabled = false;
DropDownPanel.HorizontalScroll.Visible = false;
DropDownPanel.HorizontalScroll.Maximum = 0;
DropDownPanel.AutoScroll = true;
DropDownPanel.Leave += DropDownPanel_Leave;
return DropDownPanel;
}
Here's my userControl Load Event:
private void GbComboBox_Load(object sender, EventArgs e)
{
_dropDownPanel = DropDownPanel();
this.Parent.Parent.Controls.Add(_dropDownPanel);
RelocateDropDownPanel();
_dropDownPanel.BringToFront();
ApplyItems(_items);
}
And my calculation for the location:
private void RelocateDropDownPanel()
{
if (_dropDownPanel != null)
{
int initLocY = this.Parent.Location.Y + this.Location.Y + this.Height + _dropDownPanel.Height;
int fullHeight = this.FindForm().Height;
Point p = new Point();
if (initLocY < fullHeight)
{
p = new Point(this.Parent.Location.X + this.Location.X, initLocY - _dropDownPanel.Height);
}
else
{
p = new Point(this.Parent.Location.X + this.Location.X, initLocY - _dropDownPanel.Height - this.Height);
}
_dropDownPanel.Location = p;
}
}

So I figured out a "solution".
I simply inherited the Anchor of my Panel from the Usercontrol it was associated to.
But I wanna mention, that still, this whole thing is kind of a crappy way of dealing with custom combobox desings. As #Jimi stated in his first comment, the correct way of doing this would be to ownerdraw the combobox. I haven't done this because of specific reasons, which didn't let me do this.
A little example on how this could be made:
Change ComboBox Border Color in Windows Forms

How can I pass a parameter to control event handler?

I am creating a winforms app which generates a number of panels at runtime. I want each panel, when clicked, to open a web link.
The panels are generated at runtime:
for (int i = 0; i < meetings.Count(); i++) {
Panel door = new Panel();
door.Location = new System.Drawing.Point((i * 146) + (i * 10) + 10, 10);
door.Size = new System.Drawing.Size(146, 300);
door.BackgroundImage = ConferenceToolkit.Properties.Resources.Door;
door.Click += new EventHandler(door_Click);
Controls.Add(door);
}
and I want the event handler to point to a URL that is stored somehow in the Panel attributes. (On a web form I could use Attributes["myAttribute"] but this doesn't seem to work with WinForms):
private void door_Click(object sender, EventArgs e)
{
Panel p = sender as Panel;
Process.Start(p.Attributes["url"]);
}

There are many options for this, you may store URL in the (unused in Panel) Text property:
door.Text = FindUrl(meetings[i]);
Used like:
Process.Start(p.Text);
As alternative you may use general purpose Tag property:
door.Tag = FindUrl(meetings[i]);
With:
Process.Start(p.Tag.ToString());
Tag property is usually right place for these things and, becauase it's of type object, you can even use it to store complex types (in case you need more than a simple string).
See also similar posts for slightly more complex cases: this, this and this.

You can store the URL that you want in the Panel's Tag propertie
for example
p.Tag = "www.google.com";
and then you can use it when use cast the Panel in the on click method
reference for the .Tag property
http://msdn.microsoft.com/en-us/library/system.windows.forms.control.tag(v=vs.110).aspx

Can I give controls an index property in C# like in VB?

I've found similar answers to my question before, but not quite to what I'm trying to do...
In Visual Basic (last I used it, in 06/07) there was an "Index" property you could assign to multiple controls with the same name. I used this primarily to loop through controls, i.e.:
For i = 1 to 500
picSeat(i).Print "Hello"
Next i
Is there a way to do this in C#? I know there is a .IndexOf(), but would that really help for what I'm doing? I want to have multiple controls with the same name, just different index.
This is a Windows Form Application, and I'm using Visual Studio 2012. I am talking about controls, not arrays/lists; this was possible in VB and I was wondering if it was possible at all in C#. So I want to have, say, 30 seats in a theatre. I want to have each seat represented by a picturebox named "picSeat". VB would let me name several objects the exact same, and would assign a value to a control property "Index". That way, I could use the above loop to print "Hello" in every picture box with only 3 lines of code.

No, this feature does not exist in C#, and was never implemented in the transition from classic VB to VB.Net.
What I normally do instead is put each of the controls in question in a common parent container. The Form itself can work, but if you need to distinguish these from others of the same type a GroupBox or Panel control will work, too. Then, you access the controls like this:
foreach (var picBox in parentControl.Controls.OfType<PictureBox>())
{
// do something with each picturebox
}
If you want to use a specific control, just write by name:
pictureBox6.SomeProperty = someValue;
If you need to change a specific control determined at run-time, normally this is in response to a user event:
void PictureBox_Click(object sender, EventArgs e)
{
var picBox = sender As PictureBox;
if (picBox == null) return;
//picBox is now whichever box was clicked
// (assuming you set all your pictureboxes to use this handler)
}
If you really really want the Control Arrays feature, you can do it by adding code to create the array to your form's Load event:
PictureBox[] pictureBoxes = Me.Controls.OfType<PictureBox>().ToArray();

Are we talking WinForms here? I'm not sure, but I don't think you can have multiple controls in winforms with same name. But I vaguely recall doing something similar and the solution was to name them Button_1, Button_2 etc. Then you can iterate through all controls and get your own index.
Beware though that if you want to instanciate a separate control for each seat in a theatre, you might run into some serious performance issues :) I've done something similar to that as well and ended up drawing the whole thing on a canvas and using mouse coordinates to handle the events correctly.

You may want to check out the Uid property of controls.
(http://msdn.microsoft.com/en-us/library/system.windows.uielement.uid(v=vs.110).aspx)
You can access Control through Uid property with the following
private static UIElement FindUid(this DependencyObject parent, string uid)
{
var count = VisualTreeHelper.GetChildrenCount(parent);
if (count == 0) return null;
for (int i = 0; i < count; i++)
{
var el = VisualTreeHelper.GetChild(parent, i) as UIElement;
if (el == null) continue;
if (el.Uid == uid) return el;
el = el.FindUid(uid);
if (el != null) return el;
}
return null;
}
And simply use
var control = FindUid("someUid");
I copied code from this post

If you create an indexed dictionary of your user control, it will behave pretty much the same as in VB6, though you'll not see it on the VS C# GUI. You'll have to get around the placement issues manually. Still - and most importantly -, you'll be able to refer to any instance by the index.
The following example is for 3 pieces for clarity, but of course you could automate every step of the process with appropriate loops.
public partial class Form1 : Form
{
...
Dictionary<int, UserControl1> NameOfUserControlInstance = new Dictionary<int, UserControl1>()
{
{ 1, new UserControl1 {}},
{ 2, new UserControl1 {}},
{ 3, new UserControl1 {}}
};
private void Form1_Load(object sender, EventArgs e)
{
NameOfUserControlInstance[1].Location = new System.Drawing.Point(0, 0);
NameOfUserControlInstance[2].Location = new System.Drawing.Point(200, 0);
NameOfUserControlInstance[3].Location = new System.Drawing.Point(400, 0);
Controls.Add(NameOfUserControlInstance[1]);
Controls.Add(NameOfUserControlInstance[2]);
Controls.Add(NameOfUserControlInstance[3]);
}
...
}

I like using Tags to apply any type of meta data about the controls
for (int i = 0; i< 10; ++i)
{
Button button = new Button();
button.Tag = i;
}

Links inside rich textbox?

I know that richtextboxes can detect links (like http://www.yahoo.com) but is there a way for me to add links to it that looks like text but its a link? Like where you can choose the label of the link? For example instead of it appearing as http://www.yahoo.com it appears as Click here to go to yahoo
edit: forgot, im using windows forms
edit: is there something thats better to use (as in easier to format)?

Of course it is possible by invoking some WIN32 functionality into your control, but if you are looking for some standard ways, check this post out:
Create hyperlink in TextBox control
There are some discussions about different ways of integration.
greetings
Update 1:
The best thing is to follow this method:
http://msdn.microsoft.com/en-us/library/f591a55w.aspx
because the RichText box controls provides some functionality to "DetectUrls". Then you can handle the clicked links very easy:
this.richTextBox1.LinkClicked += new System.Windows.Forms.LinkClickedEventHandler(this.richTextBox1_LinkClicked);
and you can simple create your own RichTextBox contorl by extending the base class - there you can override the methods you need, for example the DetectUrls.

Here you can find an example of adding a link in rich Textbox by linkLabel:
LinkLabel link = new LinkLabel();
link.Text = "something";
link.LinkClicked += new LinkLabelLinkClickedEventHandler(this.link_LinkClicked);
LinkLabel.Link data = new LinkLabel.Link();
data.LinkData = #"C:\";
link.Links.Add(data);
link.AutoSize = true;
link.Location =
this.richTextBox1.GetPositionFromCharIndex(this.richTextBox1.TextLength);
this.richTextBox1.Controls.Add(link);
this.richTextBox1.AppendText(link.Text + " ");
this.richTextBox1.SelectionStart = this.richTextBox1.TextLength;
And here is the handler:
private void link_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
{
System.Diagnostics.Process.Start(e.Link.LinkData.ToString());
}

I found a way which may not be the most elegant, but it's just a few lines of code and does the job. Namely, the idea is to simulate hyperlink appearance by means of font changes, and simulate hyperlink behavior by detecting what the mouse pointer is on.
The code:
public partial class Form1 : Form
{
private Cursor defaultRichTextBoxCursor = Cursors.Default;
private const string HOT_TEXT = "click here";
private bool mouseOnHotText = false;
// ... Lines skipped (constructor, etc.)
private void Form1_Load(object sender, EventArgs e)
{
// save the right cursor for later
this.defaultRichTextBoxCursor = richTextBox1.Cursor;
// Output some sample text, some of which contains
// the trigger string (HOT_TEXT)
richTextBox1.SelectionFont = new Font("Calibri", 11, FontStyle.Underline);
richTextBox1.SelectionColor = Color.Blue;
// output "click here" with blue underlined font
richTextBox1.SelectedText = HOT_TEXT + "\n";
richTextBox1.SelectionFont = new Font("Calibri", 11, FontStyle.Regular);
richTextBox1.SelectionColor = Color.Black;
richTextBox1.SelectedText = "Some regular text";
}
private void richTextBox1_MouseMove(object sender, MouseEventArgs e)
{
int mousePointerCharIndex = richTextBox1.GetCharIndexFromPosition(e.Location);
int mousePointerLine = richTextBox1.GetLineFromCharIndex(mousePointerCharIndex);
int firstCharIndexInMousePointerLine = richTextBox1.GetFirstCharIndexFromLine(mousePointerLine);
int firstCharIndexInNextLine = richTextBox1.GetFirstCharIndexFromLine(mousePointerLine + 1);
if (firstCharIndexInNextLine < 0)
{
firstCharIndexInNextLine = richTextBox1.Text.Length;
}
// See where the hyperlink starts, as long as it's on the same line
// over which the mouse is
int hotTextStartIndex = richTextBox1.Find(
HOT_TEXT, firstCharIndexInMousePointerLine, firstCharIndexInNextLine, RichTextBoxFinds.NoHighlight);
if (hotTextStartIndex >= 0 &&
mousePointerCharIndex >= hotTextStartIndex && mousePointerCharIndex < hotTextStartIndex + HOT_TEXT.Length)
{
// Simulate hyperlink behavior
richTextBox1.Cursor = Cursors.Hand;
mouseOnHotText = true;
}
else
{
richTextBox1.Cursor = defaultRichTextBoxCursor;
mouseOnHotText = false;
}
toolStripStatusLabel1.Text = mousePointerCharIndex.ToString();
}
private void richTextBox1_MouseClick(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left && mouseOnHotText)
{
// Insert your own URL here, to navigate to when "hot text" is clicked
Process.Start("http://www.google.com");
}
}
}
To improve on the code, one could create an elegant way to map multiple "hot text" strings to their own linked URLs (a Dictionary<K, V> maybe). An additional improvement would be to subclass RichTextBox to encapsulate the functionality that's in the code above.

Many moons later there is a solution for .NET (Core), as of at least .NET 6.0 (possibly earlier) - for .NET Framework (whose latest and last version is 4.8) you'll still need one of the other solutions here:
The .Rtf property now recognizes RTF-format hyperlinks; e.g., the following renders as:
This is a true RTF hyperlink: Example Link
this.richTextBox1.Rtf = #"{\rtf1 This is a true RTF hyperlink:\line {\field{\*\fldinst HYPERLINK ""https://example.org""}{\fldrslt Example Link}}} }";

The standard RichTextBox control (assuming you are using Windows Forms) exposes a rather limited set of features, so unfortunately you will need to do some Win32 interop to achieve that (along the lines of SendMessage(), CFM_LINK, EM_SETCHARFORMAT etc.).
You can find more information on how to do that in this answer here on SO.

Can I display links in a ListView's detail mode?

I'm displaying a set of search results in a ListView. The first column holds the search term, and the second shows the number of matches.
There are tens of thousands of rows, so the ListView is in virtual mode.
I'd like to change this so that the second column shows the matches as hyperlinks, in the same way as a LinkLabel shows links; when the user clicks on the link, I'd like to receive an event that will let me open up the match elsewhere in our application.
Is this possible, and if so, how?
EDIT: I don't think I've been sufficiently clear - I want multiple hyperlinks in a single column, just as it is possible to have multiple hyperlinks in a single LinkLabel.

You can easily fake it. Ensure that the list view items you add have UseItemStyleForSubItems = false so that you can set the sub-item's ForeColor to blue. Implement the MouseMove event so you can underline the "link" and change the cursor. For example:
ListViewItem.ListViewSubItem mSelected;
private void listView1_MouseMove(object sender, MouseEventArgs e) {
var info = listView1.HitTest(e.Location);
if (info.SubItem == mSelected) return;
if (mSelected != null) mSelected.Font = listView1.Font;
mSelected = null;
listView1.Cursor = Cursors.Default;
if (info.SubItem != null && info.Item.SubItems[1] == info.SubItem) {
info.SubItem.Font = new Font(info.SubItem.Font, FontStyle.Underline);
listView1.Cursor = Cursors.Hand;
mSelected = info.SubItem;
}
}
Note that this snippet checks if the 2nd column is hovered, tweak as needed.

Use ObjectListView -- an open source wrapper around a standard ListView. It supports links directly:
This recipe documents the (very simple) process and how you can customise it.

The other answers here are great, but if you don't want to have to hack some code together, look at the DataGridView control which has support for LinkLabel equivalent columns.
Using this control, you get all the functionality of the details view in a ListView, but with more customisation per row.

You can by inheriting the ListView control override the method OnDrawSubItem.
Here is a VERY simple example of how you might do:
public class MyListView : ListView
{
private Brush m_brush;
private Pen m_pen;
public MyListView()
{
this.OwnerDraw = true;
m_brush = new SolidBrush(Color.Blue);
m_pen = new Pen(m_brush)
}
protected override void OnDrawColumnHeader(DrawListViewColumnHeaderEventArgs e)
{
e.DrawDefault = true;
}
protected override void OnDrawSubItem(DrawListViewSubItemEventArgs e)
{
if (e.ColumnIndex != 1) {
e.DrawDefault = true;
return;
}
// Draw the item's background.
e.DrawBackground();
var textSize = e.Graphics.MeasureString(e.SubItem.Text, e.SubItem.Font);
var textY = e.Bounds.Y + ((e.Bounds.Height - textSize.Height) / 2);
int textX = e.SubItem.Bounds.Location.X;
var lineY = textY + textSize.Height;
// Do the drawing of the underlined text.
e.Graphics.DrawString(e.SubItem.Text, e.SubItem.Font, m_brush, textX, textY);
e.Graphics.DrawLine(m_pen, textX, lineY, textX + textSize.Width, lineY);
}
}

You can set HotTracking to true so that when the user hovers mouse over the item it appears as link.