I am working TreeView and TreeView.Nodes in my C# GUI application and want to use the right click functionality on a few nodes in my tree. I have searched quite a bit but it seems like the SelectedNode is valid only for left click and there is nothing to capture the right click on a node. I want to add functionalities like 'Add', 'Remove', 'Rename', etc. to the nodes when right clicked upon. Any guidance please?
Thanks,
Viren
Add a handler for MouseUp.
In the handler, check the args for a right mouse button, return if it's not.
Call treeView.GetNodeAt() with the mouse coordinates to find the node.
Create a context menu.
Here's something similar for a list control which can be adapted for a TreeView:
private void listJobs_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Right)
{
int index = listJobs.IndexFromPoint(e.Location);
if (index != ListBox.NoMatches)
{
listJobs.SelectedIndex = index;
Job job = (Job)listJobs.Items[index];
ContextMenu cm = new ContextMenu();
AddMenuItem(cm, "Run", QueueForRun, job).Enabled = !job.Pending;
AddMenuItem(cm, "Cancel run", CancelQueueForRun, job).Enabled = (job.State == JobState.Pending || job.State == JobState.Running);
AddMenuItem(cm, "Open folder", OpenFolder, job);
cm.Show(listJobs, e.Location);
}
}
}
private MenuItem AddMenuItem(ContextMenu cm, string text, EventHandler handler, object context)
{
MenuItem item = new MenuItem(text, handler);
item.Tag = context;
cm.MenuItems.Add(item);
return item;
}
You may need to use PointToClient or PointToScreen on the form to translate the coordinates appropriately. You'll soon realize if you need them when the context menu appears in the wrong place.
Use the ContextMenuStrip property on the TreeView to add a context menu. If you need to not show the menu for some of the nodes, you can handle the ContextMenuStrip's Opening event to cancel it from showing itself -- or, you can disable some of the menu's options from there as well.
Edit: to grab the node under the mouse, handle the MouseUp event on the TreeView, and use this code:
TreeNode nodeUnderMouse = tvMyTreeView.GetNodeAt(e.X, e.Y);
Related
So, following this question, I have been attempting to deal with a way to stop a drop down menu from closing when I click on an item.
In the linked question, one such answer suggested that I set the AutoClose property to false. I did so, and this did achieve what I asked. However, the way I implemented it means that the Drop Down menu is forced open.
Form Code:
public void ToolStripMenuItem_Click(object sender, EventArgs e)
{
ToolStripMenuItem item = sender as ToolStripMenuItem;
if (item != null)
item.Checked = !item.Checked;
item.DropDown.AutoClose = false;
}
I know why this is - the implementation means that there is no way to allow the AutoClose to be set to true. However, since the menuItems are dynamically generated in a different class, I don't have any events or objects to refer to.
This code copies the menu structure from the Main Form, and copies it across to recreate it in the "Profile View" (to set what users can/cannot see).
Controller Code:
private void PopulateProfileView(User_AccessProfilesView view, Menu_View mainMenu)
{
// Disabled Items are not able to be set, becasue they are either always visible for every user,
// or only visible to specific users (Administrator)
List<string> disabledMenuItems = new List<string>();
List<string> disabledSubMenuItems = new List<string>();
bool error = false;
bool subError = false;
_groupDictionary = new Dictionary<string, List<string>>();
// Populate the disallowed Menu Items from the Main Menu,
// and then add the items specific to the Profile View
disabledMenuItems.Add("File");
disabledMenuItems.Add("Administrator");
disabledMenuItems.Add("Help");
disabledMenuItems.Add("Te&rminations");
disabledMenuItems.AddRange(mainMenu.disallowedMenuItems);
// Populate the disallowed Sub Menu Items from the Main Menu,
// and then add the items specific to the Profile View
disabledSubMenuItems.Add("View All");
disabledSubMenuItems.AddRange(mainMenu.disallowedSubItems);
foreach (ToolStripMenuItem item in mainMenu.mainMenuStrip.Items)
{
ToolStripMenuItem menuItem = new ToolStripMenuItem(item.Text);
if (error == false)
{
// Add to the menu bar
view.menuStrip.Items.Add(menuItem);
menuItem.Click += new EventHandler(view.ToolStripMenuItem_Click);
foreach (ToolStripItem dropItem in item.DropDownItems)
{
if (dropItem is ToolStripMenuItem)
{
ToolStripMenuItem menuDropItem = new ToolStripMenuItem(dropItem.Text);
// Same concerns as above with regards to doing a substring check
// to decide if menu items should be excluded or not.
foreach (string s1 in disabledSubMenuItems)
{
if (!menuDropItem.Text.Contains(s1))
{
subError = false;
}
else
{
subError = true;
break;
}
}
if (!subError)
{
menuItem.DropDownItems.Add(menuDropItem);
menuDropItem.Click += new EventHandler(view.ToolStripMenuItem_Click);
}
}
else if (dropItem is ToolStripSeparator)
{ menuItem.DropDownItems.Add(new ToolStripSeparator()); }
}
How do I implement the AutoClose property correctly so that if I click on a menu item, the menu won't close, but if I click on the menu header, or move the mouse away from the menu, or select another menu (either by click or mouse over), the menu does Close?
Apologies if this is a simple issue - I have been out of the game for roughly a year, and have to jump back into this and I am having a little bit of an issue following everything properly.
To solve the problem you can follow these steps:
You should determine which menu items should keep open even after clicking on them. I'll use "keepopen" as value of Tag property for those items that should be kept open after clicking.
For the menu item which contains those items, you need to get DropDown property and and handle its ItemClicked event and in the ItemClicked event, you should check if the item which is clicked is one of those "keepopen" items, then set DropDown.AutoClose of the container menu item to false. For other items, set it to true. It will prevent closing those "keepopen" item when clicking, while let other items close by click.
You should handle CheckedChanged event of those "keepopen" items and set DropDown.AutoClose to true. While using the Click event handler we prevented the items from closing, here we enable the closing again, so if the user click outside of the menu, it will close.
Then this would be the result, look at mouse clicks:
Example
As an example, create an empty form and handle its Load event and use following code. When you click on SubMenu1, SubMenu2 or SubMenu3, they will just get checked or unchecked without closing the menu. But of you click outside the menu or on SubMenu4, it will close the menu.
const string keepopen = "keepopen";
private void Form1_Load(object sender, EventArgs e)
{
var menuStrip = new MenuStrip() { Dock = DockStyle.Top };
this.Controls.Add(menuStrip);
var menu1 = (ToolStripMenuItem)menuStrip.Items.Add("Menu1");
menu1.DropDownItems.Add(new ToolStripMenuItem("Submenu1")
{ Tag = keepopen, CheckOnClick = true });
menu1.DropDownItems.Add(new ToolStripMenuItem("Submenu2")
{ Tag = keepopen, CheckOnClick = true });
menu1.DropDownItems.Add(new ToolStripMenuItem("Submenu3")
{ Tag = keepopen, CheckOnClick = true });
menu1.DropDownItems.Add("-");
menu1.DropDownItems.Add(new ToolStripMenuItem("Submenu4"));
menu1.DropDown.ItemClicked += (obj, args) =>
{
if (args.ClickedItem.Tag == keepopen)
menu1.DropDown.AutoClose = false;
else
menu1.DropDown.AutoClose = true;
};
menu1.DropDownItems.OfType<ToolStripMenuItem>()
.Where(x => x.Tag == keepopen)
.ToList().ForEach(x =>
{
x.CheckedChanged += (obj, args) =>
{
menu1.DropDown.AutoClose = true;
};
});
}
I am using the TreeView from the WinrtXamlToolkit. The default behavior of this control is to expand the nested items on double click of the header. The code responsible for this is here (TreeViewItem.cs line 1205).
private void OnHeaderMouseLeftButtonDown(object sender, PointerRoutedEventArgs e)
{
if (Interaction.AllowMouseLeftButtonDown(e))
{
// If the event hasn't already been handled and this item is
// focusable, then focus (and possibly expand if it was double
// clicked)
if (!e.Handled && IsEnabled)
{
if (Focus(FocusState.Programmatic))
{
e.Handled = true;
}
// Expand the item when double clicked
if (Interaction.ClickCount % 2 == 0)
{
bool opened = !IsExpanded;
UserInitiatedExpansion |= opened;
IsExpanded = opened;
e.Handled = true;
}
}
Interaction.OnMouseLeftButtonDownBase();
OnPointerPressed(e);
}
}
Is there a way to change this behavior to expand the items on single click or tap without actually copying the control and all it's related classes to my project?
It seems like an overkill to do this just to change a few lines of code.
I tried to do drag'n'drop stuff with that TreeView and was in a similar situation. My first move was to actually copy all the TreeView and its related classes and man there are a lot. There's a lot of internal stuff happening and I pretty much gave up interfering with it after a bunch of other stuff stopped working.
So my solution was to just have a specific control inside the ItemTemplate that handled dragging for me. For you this would be a Button whose Click you handle. In the eventhandler you will navigate up the visual tree to your TreeViewItem and change the IsExpanded.
Probably this question has already an answer here but I was not able to find it..
I have a tabControl with a flowlayoutpanel in each tab page where I can add controls at run time. I can rearrange them, move them across tab pages.. How can I select multiple controls to be able to move them around using ctrl key + mouse click?
This is my drag event so far:
private void control_DragDrop(object sender, DragEventArgs e)
{
Control target = new Control();
target.Parent = sender as Control;
if (target != null)
{
int targetIndex = FindCSTIndex(target.Parent);
if (targetIndex != -1)
{
string cst_ctrl = typeof(CustomControl).FullName;
if (e.Data.GetDataPresent(cst_ctrl))
{
Button source = new Button();
source.Parent = e.Data.GetData(cst_ctrl) as CustomControl;
if (targetIndex != -1)
fl_panel = (FlowLayoutPanel)tabControl1.SelectedTab.Controls[0];
if (source.Parent.Parent.Name == target.Parent.Parent.Parent.Name)
{
this.fl_panel.Controls.SetChildIndex(source.Parent, targetIndex);
}
else
{
target.Parent.Parent.Parent.Controls.Add(source.Parent);
this.fl_panel.Controls.SetChildIndex(source.Parent, targetIndex);
}
}
}
}
}
private int FindCSTIndex(Control cst_ctr)
{
fl_panel = (FlowLayoutPanel)tabControl1.SelectedTab.Controls[0];
for (int i = 0; i < this.fl_panel.Controls.Count; i++)
{
CustomControl target = this.fl_panel.Controls[i] as CustomControl;
if (cst_ctr.Parent == target)
return i;
}
return -1;
}
This is not an easy, nor a common task. But surely doable and depending on preconditions could become trivial without need to spend multi-man-year effort on it ^^.
You have many options:
controls support selection;
container control support children controls selection;
overlay.
Handling selection is pretty easy: have a dictionary (or a control property, possibly using Tag) to store if control is selected or not, show selection somehow, when control is Ctrl-clicked invert selection. You can even provide Shift-key selection.
As #Hans Passant commented, you can use overlay window (invisible window on top of everything) to draw selection reticle there as well as handle selection and dragging itself. Or it could be a custom control with property IsSelected, setting which will draw something (border?) to indicate selection.
Easiest option would be to create SelectionPanel control, which can host any other controls inside, has IsSelected indication and is draggable. When children is added subscribe to MouseUp/MouseDown events or you can only allow to drag if special area of SelectionPanel is clicked. To example, you could have option Enable dragging in your software, when set all SelectionPanels will display special area (header?) which you can drag or Ctrl-click.
I have a TreeView control for which each node in it I want to share a ContextMenuStrip which has two ToolStripMenuItems ie:
this.BuildTree = new MyApp.MainForm.TreeView();
this.ItemMenuStrip = new System.Windows.Forms.ContextMenuStrip(this.components);
this.DeleteMenuItem = new System.Windows.Forms.ToolStripMenuItem();
this.ShowLogMenuItem = new System.Windows.Forms.ToolStripMenuItem();
...
this.ItemMenuStrip.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
this.DeleteMenuItem,
this.ShowLogMenuItem});
So I show and hide these to items according to certain criteria on a right click in a MouseUp event. When both are hidden I hide the ContextMenuStrip itself. Problem is when I hide the ContextMenuStrip it seems the next time I want to show one of the menu items I have to click twice on the node. The strange thing is on the first click to reshow one or both of the the items I have the following code:
ItemMenuStrip.Visible = true;
ShowLogMenuItem.Visible = true;
The two lines above don't seem to do anything ie both remain false in the debugger view after stepping over each line.
I don't think I've got any events on these values being set at least I don't have any events attached.
What am I doing wrong?
I suggest you to set:
this.BuildTree.ContextMenuStrip = this.ItemMenuStrip;
to make the menu automatically open on tree right-click.
Then subscribe ItemMenuStrip.Opening event to change the visibility of items and the contextmenu itself:
void ItemMenuStrip_Opening(object sender, CancelEventArgs e)
{
if (something)
{
e.Cancel = true; // don't show the menu
}
else
{
// show/hide the items...
}
}
If you need to know the current position of the clicked point (e.g. to check if a tree node is clicked), you can use Control.MousePosition property. Note that MousePosition is a point in screen coordinates, so you need to call treeView1.PointToClient(position) to get the tree coordinates e.g. :
private void ItemMenuStrip_Opening(object sender, CancelEventArgs e)
{
var pointClicked = this.BuildTree.PointToClient(Control.MousePosition);
var nodeClicked = this.BuildTree.GetNodeAt(pointClicked);
if (nodeClicked == null)
{
// no tree-node is clicked --> don't show the context menu
e.Cancel = true;
}
else
{
// nodeClicked variable is the clicked node;
// show/hide the context menu items accordingly
}
}
So figured out what was going wrong I was setting Visible on this.ItemMenuStrip rather than the this.BuildTree.ContextMenuStrip.
This seems rather strange to me as I would have thought BuildTree.ContextMenuStrip was just a direct reference to the ItemMenuStrip but apparently not.
I would need to know how to let the programatically selected node make graphically in the state "selected" like the user clicked on it. SelectedNode only makes this one internally selected. Thank you very much!
The reason it does not show as highlighted is due to the tree view not having focus. This is in a button click event on my test form:
TreeView1.SelectedNode = TreeView1.Nodes(2);
TreeView1.Focus();
Which highlights the node properly. if you remove the Focus(); call it doesn't highlight until you click into the tree view (anywhere in the tree view, not necessarily on to the node that you want to be selected).
TreeView1.SelectedNode.BackColor = SystemColors.HighlightText; // This will work
Above solutions will only set the focus on it but will not change the highlight view of it.
This works for me for .net 3.5:
Set the treeview component's DrawMode property to: OwnerDrawAll
Then in the DrawNode event write the following:
if (((e.State & TreeNodeStates.Selected) != 0) && (!MyTreeView.Focused))
e.Node.ForeColor = Color.Blue;
else
e.DrawDefault = true;
And in the BeforeSelect event have:
if (MyTreeView.SelectedNode != null)
MyTreeView.SelectedNode.ForeColor = Color.Black;
e.Node.ForeColor = Color.Blue;
I don't know if it helps you or not but check the taborder of the the page and make sure that the tree view control has tab order of 0
Here is what I got to work:
void myProcedure()
{
// Hookup a DrawMode Event Handler
this.myTV.DrawNode += myTV_DrawNode;
// Set DrawMode and HideSelection
this.myTV.DrawMode = TreeViewDrawMode.OwnerDrawText;
this.myTV.HideSelection = false;
// Make sure the TreeView has Focus
this.myTV.Focus();
// Make sure the TreeView is Selected
this.myTV.Select();
// If the TreeView has a Node, I want to select the first Node to demonstrate.
if (this.myTV.Nodes.Count > 0)
{
// Make sure the node is visible
this.myTV.Nodes[0].EnsureVisible();
// Make sure the Node is Selected
this.myTV.SelectedNode = myTV.Nodes[0];
}
// Make sure the SelectedNode IS the Node that we programmatically want to select.
textBox1.Text = this.myTV.SelectedNode.Text;
// if we display sanityCheck1 string, it actually is the correct node.text
// Make sure .NET runtime knows the Node is selected
textBox1.Text += " is Selected = " + this.myTV.SelectedNode.IsSelected.ToString();
}
Following up: laalto answered the How to HighLight the TreeView.Node. The following code in the DrawNode Event Handler, from samball's answer, properly highlights the TreeView.Node based on its Selected State.
private void myTV_DrawNode(object sender, DrawTreeNodeEventArgs e)
{
// first, let .NET draw the Node with its defaults
e.DrawDefault = true;
// Now update the highlighting or not
if (e.State == TreeNodeStates.Selected)
{
e.Node.BackColor = SystemColors.Highlight;
e.Node.ForeColor = SystemColors.HighlightText;
}
else
{
e.Node.BackColor = ((TreeView)sender).BackColor;
e.Node.ForeColor = ((TreeView)sender).ForeColor;
}
}
Platform = C# .NET 4.5 in Windows 10, Visual Studio 2015
TreeView1.SelectedNode = TreeView1.Nodes(2);
this.ActiveControl = TreeView1;
This works for me (.net 4.7)
The underlying Win32 control supports this (think it's TVIS_DROPHILITED), but I can't see the same functionality exposed through the TreeView control.
As theraneman says, you could fake it with the TreeNode.ForeColor and BackColor properties...
I had an similar issue and wanted to have a TreeView node selected (highlighted) on form load.
Maybe someone has the same problem, too.
I first tried Pondidum's solution. Without success.
But then I found the solution in another thread: Simply set the TabIndex of the TreeView to 0.
In that case you don't need to set the focus. Just choose the node that should be selected by using SelectedNode and set the TabIndex. That's it.
Not sure, but can you not change the background color of that node?