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TabPage from tabcontrol does not show data in C# Winforms

I am facing issue in tabcontrol of Windows application.
We have a tabcontrol on 1 windows form on which first tab is by default and other tabs we are adding dynamically at runtime.
In first case while we opening the form, we able to see all the controls in both the tabs i.e. (Default and other tabs)
Although, when we try opening the form for second time, data is being getting added into the form if we debug but while showing, it shows blank in other tabs which are getting added dynamically.
In CustomgroupControl class, i am adding controls dynamically like textbox, dropdown, grid and etc. Although this is working in first case, but not showing controls in second case. (Flow of code is same for both the cases)
Below is attached screenshot in link and shown sample source code
Screenshot for above query
public void renderTabpage(Dictionary<string, List<Field>> subHeaderMap, TabPage currentTabPage, AsynchTabRenderer asynchTabRenderer, DoWorkEventArgs e)
{
currentTabPage.SuspendLayout();
TableLayoutPanel headerTableLayout = createNewheaferTableLayoutPanel(currentTabPage.Name + TABLE_LAYOUT_NAME_SUFFIX);
currentTabPage.Controls.Add(headerTableLayout);
headerTableLayout.ColumnCount = 1;
headerTableLayout.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100F));
headerTableLayout.RowCount = 0;
headerTableLayout.SuspendLayout();
foreach (string subHeaderName in subHeaderMap.Keys)
{
if (asynchTabRenderer != null && asynchTabRenderer.CancellationPending == true)
{
e.Cancel = true;
return;
}
else
{
CustomGroupControl customGroupControl = createAndPopulateSubheaderGroupControl(subHeaderMap[subHeaderName], subHeaderName);
headerTableLayout.RowCount = headerTableLayout.RowCount + 1;
headerTableLayout.RowStyles.Add(new RowStyle(SizeType.AutoSize));
headerTableLayout.Controls.Add(customGroupControl, 0, ++headerTableLayout.RowCount);
}
}
headerTableLayout.ResumeLayout(false);
headerTableLayout.PerformLayout();
currentTabPage.ResumeLayout(false);
currentTabPage.PerformLayout();
}
private void detailsTabControl_TabIndexChanged(object sender, EventArgs e)
{
tabIndexChangedEvent(((TabControl)sender).SelectedTab);
}
private void tabIndexChangedEvent(TabPage tabPage)
{
try
{
//WordApp.ScreenUpdating = false;
//WordApp.System.Cursor = Word.WdCursorType.wdCursorWait;
if (tabPage.Name == TabName.Replace(" ", "_").ToUpper())
{
FileUtilService service = FileUtilFactory.getInstance();
// service.clearIENetCache();
showForm(Window, forms);
}
//TabPage tabPage = ((TabControl)sender).SelectedTab;
if ((tabPage.Tag == null || true == (Boolean)tabPage.Tag) && !string.Equals(tabPage.Name, FieldConstants.TAB, StringComparison.CurrentCultureIgnoreCase))
{
var controls = WindowsFormControlUtils.GetControlHierarchy(tabPage);
foreach (Control control in controls)
{
if (control is CustomGroupControl)
{
CustomGroupControl customGroupControl = (CustomGroupControl)control;
customGroupControl.fieldRenderDelegater();
}
else
continue;
}
tabPage.Tag = false;
}
}
catch (Exception ex)
{
logger.Error(ex.Message);
}
}
internal TableLayoutPanel createNewheaferTableLayoutPanel(string headerName)
{
TableLayoutPanel subHeaderTableLayout = new TableLayoutPanel();
// resources.ApplyResources(subHeaderTableLayout, headerName.Replace(" ", "_").ToUpper());
subHeaderTableLayout.Name = headerName.Replace(" ", "_").ToUpper() + TABLE_LAYOUT_NAME_SUFFIX;
subHeaderTableLayout.Dock = DockStyle.Fill;
subHeaderTableLayout.AutoSize = true;
subHeaderTableLayout.AutoScroll = true;
subHeaderTableLayout.AutoSizeMode = System.Windows.Forms.AutoSizeMode.GrowOnly;
subHeaderTableLayout.GrowStyle = TableLayoutPanelGrowStyle.AddRows;
return subHeaderTableLayout;
}

#Jimi & #Lucky
It works. Got the correct direction. Thanks.
Hint - Don't create controls on worker thread
Tried solution and worked - Removed creation of controls from parameterized constructor and added on form_load event.

AutoScroll problem when using Left Dock - C# Telerik Winforms

Here is my code:
RadScrollablePanel panel = new RadScrollablePanel() { AutoScroll = true, Dock = DockStyle.Fill};
pnlclp.PanelContainer.Controls.Add(panel);
foreach (var date in dates)
panel.Controls.Add(new ucDetails() { Dock = DockStyle.Left });
I'm adding some controls inside a RadScrollablePanel and then adding it into a PanelContainer.
Everything works great. If I add so many controls inside the RadScrollablePanel which is not visible in first look, the scroll bar will be shown as well.
But If I change the DockStyle.Left to DockStyle.Right in foreach loop, after loading the controls, it will not show the scroll bar and it is strange and I can not find any reason or solution to solve this issue.
I even try to change the RightToLeft property of RadScrollablePanel. but no success :(
Any suggestion?

Following the provided information, I have prepared a sample project to test the behaior in RadScrollablePanel.
I have logged it in our feedback portal by creating a public thread. You can track its progress, subscribe for status changes and add your comments on the following link: https://feedback.telerik.com/winforms/1453253-radscrollablepanel-missing-scrollbar-when-there-is-no-enough-space-to-display-the-content-controls
I hope this information helps.

To work around this problem of the standard Microsoft WinForms Panel, I can suggest docking all the UserControls to the Left and use an empty Panel that occupies all the available space on the left of the form, so exactly the same behavior as all UserControls are docked to the Right. When the size of the form is changed adjust the width of the empty panel. The described approach is illustrated with the code below:
public partial class Form1 : Form
{
UserControl1[] userControls;
RadScrollablePanel parentPanel;
Panel spacePanel;
public Form1()
{
InitializeComponent();
new Telerik.WinControls.RadControlSpy.RadControlSpyForm().Show();
}
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
this.parentPanel = new RadScrollablePanel();
this.parentPanel.Dock = DockStyle.Fill;
this.parentPanel.BackColor = Color.Yellow;
this.Controls.Add(this.parentPanel);
this.parentPanel.AutoScroll = true;
int count = 10;
this.userControls = new UserControl1[count];
for (int i = 0; i < count; i++)
{
this.userControls[i] =
new UserControl1()
{
Dock = DockStyle.Left,
BackColor = Color.FromKnownColor((KnownColor)(i + 50))
};
this.parentPanel.Controls.Add(this.userControls[i]);
}
this.spacePanel = new Panel();
this.spacePanel.Dock = DockStyle.Left;
this.parentPanel.Controls.Add(this.spacePanel);
}
protected override void OnSizeChanged(EventArgs e)
{
base.OnSizeChanged(e);
if (this.spacePanel != null)
{
int lastPanelWidth = this.parentPanel.Width;
foreach (Control control in this.parentPanel.PanelContainer.Controls)
{
if (control.Dock == DockStyle.Left && control != this.spacePanel)
{
lastPanelWidth -= control.Width;
}
}
if (lastPanelWidth < 0)
{
lastPanelWidth = 0;
}
this.spacePanel.Width = lastPanelWidth;
}
}
}

TabPage title alignment being wrong after drag'n'dropping

I have the class that extends System.Windows.Forms.TabControl and had implemented drag'n'drop mechanism for its TabPages as following:
#region Overriden base methods
protected override void OnDragOver(DragEventArgs e)
{
if (PointedTabPage == null) return;
e.Effect = DragDropEffects.Move;
var dragTab = e.Data.GetData(typeof (ManagedTabPage)) as ManagedTabPage;
if (dragTab == null) return;
int dropIndex = TabPages.IndexOf(PointedTabPage);
int dragIndex = TabPages.IndexOf(dragTab);
if (dragIndex == dropIndex) return;
var modifiedTabPages = new List<ManagedTabPage>(from ManagedTabPage tabPage in TabPages
where TabPages.IndexOf(tabPage) != dragIndex
select TabPages[TabPages.IndexOf(tabPage)] as ManagedTabPage);
modifiedTabPages.Insert(dropIndex, dragTab);
for (byte i = 0; i < TabPages.Count; ++i)
{
var managedTabPage = TabPages[i] as ManagedTabPage;
if (managedTabPage != null && managedTabPage.Uid == modifiedTabPages[i].Uid)
continue;
TabPages[i] = modifiedTabPages[i];
}
SelectedTab = dragTab;
}
protected override void OnMouseDown(MouseEventArgs e)
{
try
{
switch (e.Button)
{
case MouseButtons.Left:
DoDragDrop(PointedTabPage, DragDropEffects.Move);
break;
case MouseButtons.Middle:
CloseTab(PointedTabPage);
break;
}
}
catch (InvalidOperationException)
{
}
finally
{
TabPages.Insert(0, String.Empty);
TabPages.RemoveAt(0);
}
}
#endregion
Nota bene that in the finally clause of OnMouseDown method there are 2 lines for workarounding the
problem: for some reason w/o these lines after drag'n'dropping any of TabPages alignment of their titles is being wrong:
What should I do to correct this behavior without this smelly workaround? Maybe sending some Windows messages could do the trick?
Thanks a lot for any suggestions.
Edit 1. Code of ManagedTabPage is 100% unimportant (it's just extends TabPage with some specific properties).
PointedTabPage is unimportant too, but this is it:
return (from ManagedTabPage tabPage in TabPages
let tabPageIndex = TabPages.IndexOf(tabPage)
where GetTabRect(tabPageIndex).Contains(PointToClient(Cursor.Position))
select TabPages[tabPageIndex]).Single() as ManagedTabPage;
I'm trying to achieve fully-centered alignment of labels. You see, labels on the screenshot didn't centered horizontally?

I can't do much with the posted code. Let's take a completely different tack and create a tabcontrol that supports dragging a tabpage with the mouse. Add a new class to your project and paste this code:
using System;
using System.Drawing;
using System.Windows.Forms;
class TabControlEx : TabControl {
private Point downPos;
private Form draggingHost;
private Rectangle draggingBounds;
private Point draggingPos;
public TabControlEx() {
this.SetStyle(ControlStyles.UserMouse, true);
}
}
The usage of the variable becomes clear later. First thing we need is to get mouse events from the TabControl so we can see the user trying to drag a tab. That requires turning on the UserMouse control style, it is off by default for controls (like TabControl) that are built-in Windows controls and use their own mouse handling.
Use Build > Build and drag the new control from the top of the toolbox onto a form. Everything still looks and acts like a regular TabControl, but do note that clicking tabs no longer changes the active tab. A side-effect of turning the UserMouse style on. Let's fix that first, paste:
protected override void OnMouseDown(MouseEventArgs e) {
for (int ix = 0; ix < this.TabCount; ++ix) {
if (this.GetTabRect(ix).Contains(e.Location)) {
this.SelectedIndex = ix;
break;
}
}
downPos = e.Location;
base.OnMouseDown(e);
}
We are storing the click location, that's needed later to detect the user dragging the tab. That requires the MouseMove event, we need to start dragging when the user moved the mouse far enough away from the original click position:
protected override void OnMouseMove(MouseEventArgs e) {
if (e.Button == MouseButtons.Left && this.TabCount > 1) {
var delta = SystemInformation.DoubleClickSize;
if (Math.Abs(e.X - downPos.X) >= delta.Width ||
Math.Abs(e.Y - downPos.Y) >= delta.Height) {
startDragging();
}
}
base.OnMouseMove(e);
}
The startDragging method needs to create a toplevel window that can be moved around with the mouse, containing a facsimile of the tab we're dragging around. We'll display it as an owned window, so it is always on top, that has the exact same size as the tab control:
private void startDragging() {
draggingBounds = this.RectangleToScreen(new Rectangle(Point.Empty, this.Size));
draggingHost = createDraggingHost(draggingBounds);
draggingPos = Cursor.Position;
draggingHost.Show(this.FindForm());
}
The createDraggingHost needs to do the heavy lifting and create a window that looks just like the tab. A borderless form we'll move around with the mouse. We'll use the TransparencyKey property to make it look similar to the dragged TabPage with a tab sticking out at the top. And make it look the same by simply letting it display a screenshot of the tabpage:
private Form createDraggingHost(Rectangle bounds) {
var host = new Form() { FormBorderStyle = FormBorderStyle.None, ControlBox = false, AutoScaleMode = AutoScaleMode.None, Bounds = this.draggingBounds, StartPosition = FormStartPosition.Manual };
host.BackColor = host.TransparencyKey = Color.Fuchsia;
var tabRect = this.GetTabRect(this.SelectedIndex);
var tabImage = new Bitmap(bounds.Width, bounds.Height);
using (var gr = Graphics.FromImage(tabImage)) {
gr.CopyFromScreen(bounds.Location, Point.Empty, bounds.Size);
gr.FillRectangle(Brushes.Fuchsia, new Rectangle(0, 0, tabRect.Left, tabRect.Height));
gr.FillRectangle(Brushes.Fuchsia, new Rectangle(tabRect.Right, 0, bounds.Width - tabRect.Right, tabRect.Height));
}
host.Capture = true;
host.MouseCaptureChanged += host_MouseCaptureChanged;
host.MouseUp += host_MouseCaptureChanged;
host.MouseMove += host_MouseMove;
host.Paint += (s, pe) => pe.Graphics.DrawImage(tabImage, 0, 0);
host.Disposed += delegate { tabImage.Dispose(); };
return host;
}
Note the use of the Capture property, that's how we detect that the user released the mouse button or interrupted the operation by any other means. We'll use the MouseMove event to move the window around:
private void host_MouseMove(object sender, MouseEventArgs e) {
draggingHost.Location = new Point(draggingBounds.Left + Cursor.Position.X - draggingPos.X,
draggingBounds.Top + Cursor.Position.Y - draggingPos.Y);
}
And finally we need to handle the completion of the drag. We'll swap tabs, inserting the dragged tab at the mouse position and destroy the window:
private void host_MouseCaptureChanged(object sender, EventArgs e) {
if (draggingHost.Capture) return;
var pos = this.PointToClient(Cursor.Position);
for (int ix = 0; ix < this.TabCount; ++ix) {
if (this.GetTabRect(ix).Contains(pos)) {
if (ix != this.SelectedIndex) {
var page = this.SelectedTab;
this.TabPages.RemoveAt(this.SelectedIndex);
this.TabPages.Insert(ix, page);
this.SelectedIndex = ix;
}
break;
}
}
draggingHost.Dispose();
draggingHost = null;
}
Looks pretty good.

since you hasn't shared ManagedTabPage code, i used default TabPage control
changes are made in method OnDragOver
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
namespace Demo
{
public class MyTabControl : TabControl
{
public MyTabControl()
{
SizeMode = TabSizeMode.Fixed;
ItemSize = new Size(224, 20);
}
#region Overriden base methods
protected override void OnDragOver(DragEventArgs e)
{
if (DesignMode)
return;
if (PointedTabPage == null) return;
e.Effect = DragDropEffects.Move;
var dragTab = e.Data.GetData(typeof(TabPage)) as TabPage;
if (dragTab == null) return;
int dropIndex = TabPages.IndexOf(PointedTabPage);
int dragIndex = TabPages.IndexOf(dragTab);
if (dragIndex == dropIndex) return;
// change position of tab
TabPages.Remove(dragTab);
TabPages.Insert(dropIndex, dragTab);
SelectedTab = dragTab;
base.OnDragOver(e);
}
protected override void OnMouseDown(MouseEventArgs e)
{
if (DesignMode)
return;
switch (e.Button)
{
case MouseButtons.Left:
DoDragDrop(PointedTabPage, DragDropEffects.Move);
break;
case MouseButtons.Middle:
TabPages.Remove(PointedTabPage);
break;
}
}
#endregion
TabPage PointedTabPage
{
get
{
return TabPages.OfType<TabPage>()
.Where((p, tabPageIndex) => GetTabRect(tabPageIndex).Contains(PointToClient(Cursor.Position)))
.FirstOrDefault();
}
}
}
}

Switching Panels via Index Methods

I've been trying to solve my issue for quite a while and to be honest am getting nowhere. What i would like is when the user clicks the 'top' button on my panel it automatically goes to the top( and swaps with the one there.) and when they click the bottom button it automatically goes to the bottom. I'm setting the index panel manually but of course this doesnt work because its only viable for one panel (i have ten). Greatly appreciate some help in finding a method that can send the panel to the top of the stack regardless of its position.
Here is a image (basic) to help understand
Control ctrlToMove = (Control)this.bookControls[bookName];
int ctrlToMoveIndex = bookPanel.Controls.IndexOf(ctrlToMove);
int ctrlToSwapIndex = ctrlToMoveIndex - 5;
Control ctrlToSwap = bookPanel.Controls[ctrlToSwapIndex];
this.bookPanel.Controls.SetChildIndex(ctrlToMove, ctrlToSwapIndex);
this.bookPanel.Controls.SetChildIndex(ctrlToSwap, ctrlToMoveIndex);

Based on your drawing, I made a UserControl with a button on it:
void uc_ButtonClicked(object sender, EventArgs e) {
UserControl1 uc = sender as UserControl1;
if (uc != null) {
int childIndex = flowLayoutPanel1.Controls.GetChildIndex(uc);
if (childIndex > 0) {
UserControl1 ucTop = flowLayoutPanel1.Controls[0] as UserControl1;
flowLayoutPanel1.Controls.SetChildIndex(uc, 0);
flowLayoutPanel1.Controls.SetChildIndex(ucTop, childIndex);
}
}
}

According to your picture you have one control per row in panel. Thus I suggest you to use TableLayoutPanel instead of FlowLayoutPanel. Also I'd create user control for items in panel. E.g. it will have name PriorityUserControl and four buttons to increase, decrease, maximize, minimize it's 'priority' (I placed buttons horizontally just to save place on screen):
Next, create four events in this user control:
public event EventHandler PriorityMaximized;
public event EventHandler PriorityIncreased;
public event EventHandler PriorityDecreased;
public event EventHandler PriorityMinimized;
And rise appropriate event when button clicked:
private void topButton_Click(object sender, EventArgs e)
{
if (PriorityMaximized != null)
PriorityMaximized(this, EventArgs.Empty);
}
That's it. We have user control which tells whether it want to move up or down. Now add user controls to TableLayoutPanel (either manually or dynamically) and subscribe same event handlers of these four events to ALL user controls. Something like:
// create user control and attach event handlers
PriorityUserControl control = new PriorityUserControl();
control.PriorityMaximized += priorityUserControl_PriorityMaximized;
control.PriorityMinimized += priorityUserControl_PriorityMinimized;
control.PriorityIncreased += priorityUserControl_PriorityIncreased;
control.PriorityDecreased += priorityUserControl_PriorityDecreased;
// add another row to table
panel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
panel.RowCount = panel.RowStyles.Count;
// add control table layout panel
panel.Controls.Add(control);
panel.SetRow(control, panel.RowCount - 1);
Good. All you should do now is implement these event handlers. It's simple. E.g. decreasing priority (i.e. moving down):
private void priorityUserControl_PriorityDecreased(object sender, EventArgs e)
{
// sender is a control where you clicked Down button
Control currentControl = (Control)sender;
// get position in panel
var position = panel.GetPositionFromControl(currentControl);
// just to be sure control is not one at the bottom
if (position.Row == panel.RowCount - 1)
return;
// we want to switch with control beneath current
Control controlToSwitch = panel.GetControlFromPosition(0, position.Row + 1);
// move both controls
panel.SetRow(currentControl, position.Row + 1);
panel.SetRow(controlToSwitch, position.Row);
}
Now implementation of maximizing priority (i.e. moving to top):
private void priorityUserControl_PriorityMaximized(object sender, EventArgs e)
{
Control currentControl = (Control)sender;
var position = panel.GetPositionFromControl(currentControl);
if (position.Row == 0 || panel.RowCount < 2)
return;
Control topControl = panel.GetControlFromPosition(0, 0);
panel.SetRow(currentControl, 0);
panel.SetRow(topControl, position.Row);
}
I believe you will create rest two handlers by yourself.

The key of what you want is setting up a clear and extendable algorithm capable to deal with the different positions of the Panels. Here you have a simple code showing certain approach to this problem:
public partial class Form1 : Form
{
int[] panelLocations;
Point[] pointLocations;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
panelLocations = new int[5];
pointLocations = new Point[5];
panelLocations[1] = 1;
panelLocations[2] = 2;
panelLocations[3] = 3;
pointLocations[1] = new Point(panel1.Left, panel1.Top);
pointLocations[2] = new Point(panel2.Left, panel2.Top);
pointLocations[3] = new Point(panel3.Left, panel3.Top);
}
private void relocate(int curPanel, bool goTop)
{
int curLoc = panelLocations[curPanel];
int newLoc = curLoc - 1;
if (!goTop)
{
newLoc = curLoc + 1;
}
if (newLoc < 1) newLoc = 3;
if (newLoc > 3) newLoc = 1;
if (newLoc != curLoc)
{
int otherIndex = Array.IndexOf(panelLocations, newLoc);
panelLocations[curPanel] = newLoc;
relocatePanel(curPanel);
panelLocations[otherIndex] = curLoc;
relocatePanel(otherIndex);
}
}
private void relocatePanel(int curIndex)
{
if (curIndex == 1)
{
panel1.Location = pointLocations[panelLocations[1]];
}
else if (curIndex == 2)
{
panel2.Location = pointLocations[panelLocations[2]];
}
else if (curIndex == 3)
{
panel3.Location = pointLocations[panelLocations[3]];
}
}
private void buttonTop1_Click(object sender, EventArgs e)
{
relocate(1, true);
}
private void buttonBottom1_Click(object sender, EventArgs e)
{
relocate(1, false);
}
}
Open a new project, add 3 panels (Panel1, Panel2 and Panel3... better put different background colors) and include two buttons (buttonUp and buttonDown). This code will make the Panel1 to go up and down (by changing its position with the other panels).
The idea is pretty simple: at the start you store the positions of all the Panels in an array. In another array, you store where each panel is located every time (1 is the original position of Panel1, etc.).
It is a quite simple code which you can improve and extend as much as required, but the idea is pretty reliable and you can use it in any case: a set of fixed positions through which the panels will be moving.

Leaving the dropdown enabled

I want to disable a combobox, but at the same time I want to let the users see the other options available (that is, I want to enable the dropdown).
By default, when ComboBox.Enabled = false, the dropdown is also disabled (nothing happens when we click on the combobox).
My first thought is to leave it enabled and handle the ComboBox.SelectedIndex event to set it back to the default value (I will just need to gray it out in some way.)
I am wondering if there is any native functionality like this that I am missing, or if there would be other way of doing it.

Don't use a Combobox if you don't want the Combobox functionality. Use a ListView instead.

A "What You See Is What You Can't Get" Combobox seems a bad idea.
I suggest using ListBox instead.

It's a hacky workaround, but it should accomplish something similar to your request:
public partial class Form1 : Form
{
ComboBox _dummy;
public Form1()
{
InitializeComponent();
// set the style
comboBox1.DropDownStyle =
System.Windows.Forms.ComboBoxStyle.DropDownList;
// disable the combobox
comboBox1.Enabled = false;
// add the dummy combobox
_dummy = new ComboBox();
_dummy.Visible = false;
_dummy.Enabled = true;
_dummy.DropDownStyle = ComboBoxStyle.DropDownList;
this.Controls.Add(_dummy);
// add the event handler
MouseMove += Form1_MouseMove;
}
void Form1_MouseMove(object sender, MouseEventArgs e)
{
var child = this.GetChildAtPoint(e.Location);
if (child == comboBox1)
{
if (!comboBox1.Enabled)
{
// copy the items
_dummy.Items.Clear();
object[] items = new object[comboBox1.Items.Count];
comboBox1.Items.CopyTo(items, 0);
_dummy.Items.AddRange(items);
// set the size and position
_dummy.Left = comboBox1.Left;
_dummy.Top = comboBox1.Top;
_dummy.Height = comboBox1.Height;
_dummy.Width = comboBox1.Width;
// switch visibility
comboBox1.Visible = !(_dummy.Visible = true);
}
}
else if (child != _dummy)
{
// switch visibility
comboBox1.Visible = !(_dummy.Visible = false);
}
}
}

If using a ListBox as other answers suggested is not convenient. There is a way by creating a custom combobox and adding a ReadOnly property. Try this code :
class MyCombo : System.Windows.Forms.ComboBox
{
public bool ReadOnly { get; set; }
public int currentIndex;
public MyCombo()
{
currentIndex = SelectedIndex ;
}
protected override void OnSelectedIndexChanged(EventArgs e)
{
if (ReadOnly && Focused)
SelectedIndex = currentIndex;
currentIndex = SelectedIndex;
base.OnSelectedIndexChanged(e);
}
}
Usually the background color of read-only controls should not change, so I haven't done that part.