Develop Reference

How to add a ListBox programmatically in a Form

I started out C# very recently and sorry if this question sounds dumb.
How do I add a Listbox in a Form that pops out from a Button click?
Note: The Form isn't the one that's added from the Solution Explorer whereby I can just drag a Listbox from the Toolbox to my Form.
So what I want is to create a ListBox in my file drawer1Form where I can add additional items. Thanks for the help in advance!:)
private void drawer1button_Click(object sender, EventArgs e) // Drawer 1 Button
{
drawer1Form df1 = new drawer1Form();
df1.StartPosition = FormStartPosition.CenterScreen;
df1.Show();
}
public partial class drawer1Form : Form // Creates drawer1Form
{
public drawer1Form()
{
Text = "Drawer 1 ";
}
}

Pretty much the same way as you'd do with any other object.
In the class of your form add a
private ListBox myAwesomeListBox;
Then in the button event handler add something like this:
myAwesomeListBox = new ListBox();
myAwesomeListBox.SuspendLayout();
// set all the properties that you want
myAwesomeListBox.Name = "myAwesomeListBox";
myAwesomeListBox.Location = new Point(...); // place it somewhere
myAwesomeListBox.Size = new Size(...); // give it a size
// etc...
df1.Controls.Add(myAwesomeListBox);
myAwesomeListBox.ResumeLayout();
This should be it.
I highly advise you to do it through the designer first though, and then take a look at the generated code in the form's .Designer.cs file, you'll have a very good understanding after reading through that.

WinrtXamlToolkit TreeView expand with single instead of double click

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.

ObjectListView editing doesn't work

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.

Winform menustrip and hiding tabs

Hello I'm thinking of creating a tabcontrol which the tabpages will be filtered by the clicks in the menustrip.
For ex.
My menustrip is in form 1
and my tabcontrol is in form 2
My tabcontrol consist of 7 tabs and I want only 1 tab will be shown at a time.
for example If I click the name in the menustrip it will open/show a new form and the tabcontrol will only show the names tab.
I wonder if its possible because making diff forms for each list seems to be very long.
thanks for reading this.

Problem is, the TabPage control has no Visible property (well, it has, but it does nothing). So you can't hide and show tabs at will. You'll have to remove the tabs that should not be visible.
You could make a form (named TabbedForm) with code like this:
private readonly int _index;
public TabbedForm(int index)
{
this._index = index;
InitializeComponent();
}
private void form_Load(object sender, EventArgs e)
{
for (int index = this.tabControl1.TabPages.Count - 1; index >= 0; index--)
{
if (index != this._index)
this.tabControl1.TabPages.Remove(this.tabControl1.TabPages[index]);
}
}
With each menu button (Clicked event) in your main form you can open a TabbedForm with a different index.

Yes, this will work pretty fine. But I think, you must use the default tab view control for this and that must not create the problem either in you case too.

How do I get a control which looks like a TabControl with no tabs?

We have a form which displays media items in tab pages of a tab control, and I'm implementing a feature which allows users to 'pop out' the tab pages into their own forms.
However, when I add the media player to a form rather than a TabPage, the background switches from the gradient fill of a tab page to the plain SystemColors.Control background of the parent form. I need to add the the media player to a control which has the same background as a TabControl, but which doesn't display a tab at the top. I tried adding the media player to the TabControl's control collection, but that just throws an exception.
How do I get a control which looks like a TabControl with no tabs? Should I keep trying to add the media player to a TabControl, or should I try to write a Panel with a custom-drawn background? If the latter, how do I make sure that works with all possible themes?

The questions seems to be about the UseVisbleBackgroundStyle. AFAIK only buttons and TabPages have this property.
The following is a very dirty hack, just to get you started:
1) derive a customControl from Panel and add "using System.Windows.Forms.VisualStyles;"
2) Add the following code
//warning: incomplete, add error checking etc
private readonly VisualStyleElement element = VisualStyleElement.Tab.Body.Normal;
public bool UseVisbleBackgroundStyle { get; set; }
protected override void OnPaint(PaintEventArgs pe)
{
if (UseVisbleBackgroundStyle)
{
var x = new VisualStyleRenderer(element);
x.DrawBackground(pe.Graphics, this.ClientRectangle);
}
else
{
base.OnPaint(pe);
}
}

Thanks to Henk - I eventually went with:
protected override void OnPaintBackground(PaintEventArgs e)
{
if (TabRenderer.IsSupported && Application.RenderWithVisualStyles)
{
TabRenderer.DrawTabPage(pe.Graphics, this.ClientRectangle);
}
else
{
base.OnPaintBackground(pe);
ControlPaint.DrawBorder3D(pe.Graphics, this.ClientRectangle, Border3DStyle.Raised);
}
}

Try creating your own customer UserControl

This answer is modified from another answer site. It does the trick rather cleanly.
In the load event for the window containing the tab control, try:
// TabControl is the name of the tab control in this window.
TabControl.Appearance = TabAppearance.FlatButtons;
TabControl.Multiline = false;
TabControl.SizeMode = TabSizeMode.Fixed;
TabControl.ItemSize = new Size(0,1);
// The tabs are now gone. Select the panel you want to display
TabControl.SelectTab("InProgressTab");