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.
Related
I'm trying to create a simple listbox with ObjectListView (WinForm, C#). The goal is to have a single value (a double) and a check box.
I want to be able to edit the double value by Single Click, so here are the relevant lines of code from my MyWindow.Designer.cs file (i've left out the default values for efficiency):
this.olvDepths = new BrightIdeasSoftware.ObjectListView();
this.olvColumn1 = ((BrightIdeasSoftware.OLVColumn)(new BrightIdeasSoftware.OLVColumn()));
...
this.olvDepths.CellEditActivation = BrightIdeasSoftware.ObjectListView.CellEditActivateMode.SingleClick;
this.olvDepths.CheckBoxes = true;
this.olvDepths.CheckedAspectName = "IsDefault";
this.olvDepths.FullRowSelect = true;
//
// olvColumn1
//
this.olvColumn1.AspectName = "Depth";
this.olvColumn1.Text = "";
this.olvColumn1.IsEditable = true;
I then create a list of my class (ShieldingEntry) and use the olvDepths.SetObjects() with the list. My ShieldingEntry class looks like this:
public class ShieldingEntry
{
public double Depth { get; set; }
public bool IsDefault { get; set; }
}
However, when I click the field, it doesn't go into edit mode. I've also tried the DoubleClick, SingleClickAlways, and F2Only modes and they don't work either.
The Checkbox works fine.
************** I have additional information *********************
I've pulled and build the ObjectListView source, so I could step through it.
I put a breakpoint in the OLV StartCellEdit method and it gets called and appears to setup and select the control appropriately. It just never appears...
As I noted in the comments on the answer below, I've got this control on a tabbed dialog, and if I switch to another tab, then back, the control works fine.
What am I missing?
I've used ObjectListView before, and here is what I had to do:
Handle the CellEditStarting event. This event is raised when the cell goes into edit mode. Since OLV doesn't really have built-in editors, you have to make your own. Then handle the CellEditFinishing event to validate the data before putting it back into your model.
So first, handling the CellEditStarting event:
private void objlv_CellEditStarting(object sender, CellEditEventArgs e)
{
//e.Column.AspectName gives the model column name of the editing column
if (e.Column.AspectName == "DoubleValue")
{
NumericUpDown nud = new NumericUpDown();
nud.MinValue = 0.0;
nud.MaxValue = 1000.0;
nud.Value = (double)e.Value;
e.Control = nud;
}
}
This creates your editing control. If you want to make sure the size is right, you can set the size of the control (in this case a NumericUpDown) to the cell bounds using e.CellBounds from the event object.
This will show the editor when you click in the cell. Then you can handle the editor finished event to validate the data:
private void objlv_CellEditFinishing(object sender, CellEditEventArgs e)
{
if (e.Column.AspectName == "DoubleValue")
{
//Here you can verify data, if the data is wrong, call
if ((double)e.NewValue > 10000.0)
e.Cancel = true;
}
}
I don't think handling it is required, but its good practice to validate data from the user.
The editing control in the CellEditStarting event can be any control, even a user defined one. I've used a lot of user defined controls (like textboxes with browse buttons) in the cell editor.
[Edit]
I uploaded an example here dropbox link that seems to work. Might not be in the exact view as needed, but seems to do the job.
For anyone else with this problem. I had it specifically when trying to edit a 'null' value in a decimal? on the OLV on a tab page. Solution for me was to set UseCustomSelectionColors to 'False'. I didn't look elsewhere to see if it was reported as a bug. Seems like a bug.
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 an application build with the MVVM pattern from Josh Smith (http://msdn.microsoft.com/en-us/magazine/dd419663.aspx).
When I have several workspaces opened in my app, I want to catch the event of switching workspaces/tabs so I can save the content of the current workspace first. I have looked throught WorkspaceViewModel and ViewModelBase, but I don't know how to add that EventHandler.
I have found a solution in another post, I just had to tweak it a little bit : What is the proper way to handle multiple datagrids in a tab control so that cells leave edit mode when the tabs are changed?
Basically I have added an EventHandler on PreviewMouseDown of my TabControl generating the different Workspaces.
private void TabControl_PreviewMouseDown(object sender, MouseButtonEventArgs e) {
MainWindow_VM dc = (MainWindow_VM)this.DataContext;
if (IsUnderTabHeader(e.OriginalSource as DependencyObject))
//Do what need to be done before switching workspace
// in my case, switch the focus to a dummy control so the objectContext would save everything, even the currently focused textbox
}
private bool IsUnderTabHeader(DependencyObject control)
{
if (control is TabItem)
{
return true;
}
DependencyObject parent = VisualTreeHelper.GetParent(control);
if (parent == null)
return false;
return IsUnderTabHeader(parent);
}
You should be able to bind the "Current" item of the tab to a variable in the model. When this changes, do your work.
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?