Develop Reference

How to create a custom selectionmode in winforms listbox

I have a listbox in a winforms application that I would like to give a selection behavior that is different than the built in options for the control.If I choose multi-extended, I get what we are accustomed to - ability to use shift or control to select multiple items in the list. The multi-simple option lets you select individually and leave the item selected until you delect it. I'm trying to deal with a slightly different problem that could be solved by a combination of the two options. My users want to be able to use the shift key to highligh a long list and they don't want to accidentally lose their selection if they mistakenly click on one other item in the list. My thought was to keep everything hightlighted until they click a clear button. I kind of think they are asking for something that is not what Windows is meant to do and should not be allowed to do but I thought would post the question so see if anyone has done this before.

In a property grid is there a way to unselect all grid elements programatically?

I am working on a project in which I am using a property grid to display the properties of the selected control.
The Property Grid is fixed to the left edge of the container and in the rest of the space I have the form I am designing.
On clicking a control on the form, the specific control’s property is getting selected.
In the above figure, I have selected the textbox and the textbox’s properties get shown on the propertygrid.
Here if you observe, by default, the Name property is highlighted as well.
Is there some way to unselect this property programmatically?
I have tried some suggestions online but none have helped. I am not able to find find a way to remove all selections from the PropertyGrid, but its behaviour seem to be different form a DataGrid...
Here is why I need this...
On selecting a control, if a property in the property grid is selected, then the property is getting modified.
For example, If i cut the control using Ctrl + X, the selected value in property grid is getting cut which in some cases is forcing user to set the property before modifying anything on the form.
I have tried selecting multiple controls, but in that case alse the selected property seems to be persistent

Since PropertyGrid uses DefaultProperty to select a property in its grid, as an option you can set DefaultProperty attribute at run-time for your object to a non-browsable property, for example:
this.propertyGrid1.SelectedObject = null;
TypeDescriptor.AddAttributes(someControl,
new Attribute[] { new DefaultPropertyAttribute("Site") });
this.propertyGrid1.SelectedObject = someControl;

Well, what you are trying are hacks. It is never a good idea to do such hacks particularly if you are not the only person that use the software.
In your case, the focus should be on the designer while you interact with it. So if the user press Ctrl+X, the designer should respond to the keyboard and it should not have any effect on the property grid (as only one control can have the focus at the same time).
Thus it is up to you to make sure that your designer is focusable, that it has the focus when initially displayed, that it get the focus when you press the TAB key. Pressing the TAB key again should put the focus on the property grid so that user can interact with the grid without using the keyboard.
If you have more than these 2 controls, then obviously TAB should also stop at any appropriate controls. Also, it can be a good idea to have some direct shortcuts like F4 to (show and) activate the properties pane.
If you are not able to make it works, then the best compromise would be to use another windows for the properties grid. By using a distinct Tool windows for the properties, it should not respond to the keyboard when the main windows has the focus.
Here are some links that might help you:
Panel not getting focus
Control.Focus Method() — See Remarks section.
In any case, you should not prevent Ctrl+X to works as expected when the property grid has the focus and a property is selected. Users don't like software that do not follows UI conventions.
As a software developer, you should as much as possible ensure that your application follows standard behaviors. I recommend you that you take one or 2 extra days developing your software properly instead of doing hacks.
Often, compromise to gain a few days will never be fix and will be a pain for many years. Better to do it right from the start. Unselecting an item in the property grid is not an acceptable workaround. Your manager should not allows you to do that.

Winforms UI Dynamically Displaying Parts

I came across a tutorial and some example code for an audio converter. You select the format you want to convert to from a drop down, and when you do all sorts of options appear in a previously blank area, different options based on the format you choose. It's called Audio Converter .NET and is from same author as Audio CD Ripper .NET. I can't find the tutorial, but here is a screenshot.
See how on the right there is extra controls that are not on the left. I was experimenting trying to add another category. I added it to the dropdown, but am unsure how to make it so certain fields come up when it is selected.
I understand that they create those controls for those items, but I don't see how they call the correct one when the combo box selects something. I see controls are created, but if I try to duplicate the controls into another entry in the combo box they don't show up for either the new or old one I was duplicating from.
What's the best way to go about achieving something like this?
Thanks

The easiest way is to create the controls needed for every option in the dropdown inside a panel, and simply turn it's visibility property from false to true whenever it's corresponding option is selected using the combobox's SelectedIndexChanged event handler. (And don't forget to turn the current visible panel's visibility to false)

Tab control - wait until control become enabled

I have multiple controls on one form,and when i select some value from combo box(for example 1) next control became enabled, else next control stay disabled.
Problem is that if i just press 1 and tab, after that next control became enabled, but program jump over it just like control are still disabled, and tab control selecting next control.
I need to find way how to tab check is control become enabled and go on this control,and if control are still disabled that go on next enabled control.
Thanx

You created a mousetrap for the user, very hard to escape from. Technically you can handle the keyboard navigation by trapping the Tab key before it can be used to navigate but the user still has an unsolvable problem when he wants to use the mouse to change the focus. He has nothing decent to click on.
You'll need to re-think your UI design. One possible solution is to change the ComboBox's DropDownStyle to DropDownList. Which ought to be pretty appropriate if you use its selected item to enable other controls, there should only be a limited set of valid selections. If that's not what you want then you need to do something drastic. Not necessarily limited to hiding controls instead of disabling them.

This is probably caused by the event of the combo-box you using to control your flow.
The "Changed"/"Value changed" events in most languages fire up after the control has lost focus.

You forgot to add a tag for the UI technology you are using.
If you are using WinForms, then you can try to execute the SelectNextControl method on your control that the user just edited. This will find the 'next' control for you, and activate it.

Lets assume it's winforms (playing with disabled/enabled like this in wpf is.. against mvvm rules).
Firstly, ensure what tab order/index of your controls is ok. To test, if they are all enabled, then pressing Tab should go through them in the right order. This can be seen easily
Next thing is to choose one of many possible solutions, to make 1,Tab to work:
disable Tab key navigation at all;
make controls to pass control (focus) to specific control (making tab order irrelevant);
use SelectNextControl (work best for custom controls, which when will support that tab-flow schema);
prevent focus changing, do all logic, change focus (theoretically).

C# - Menu Strip Query

I have two questions regarding the windows form menu strip:
1. How to force the form to always show the helper keys?
Currently the letter underlines are displayed only if the Alt key is pressed.
2. What is the command to cause a menu to drop down?
Usually a menu drops down after the user clicks the menu button or navigates it with the keyboard, but I want to cause a menu to drop down by pressing an interface button and I can't figure out how to do it. I tried fiddling the DropDown property, but it didn't help.

With ToolStripMenuItem there are three properties you need to look at:
ShortcutKeyDisplayString
ShortcutKeys
ShowShortcutKeys
Although the three apply to the root menu item, say File or Help, you will not be able to see the short cuts, however you should be able to enable the ShortcutKeys, set ShowShortcutKeys to true and without modifying ShortcutKeyDisplayStringhave them appear next to sub ToolStripMenuItem's.
The method you are looking for on ToolStripMenuItem is ShowDropDown(), executing this method will drop down the menu.
Example:
((ToolStripMenuItem)FileMenu.Items[0]).ShowDropDown();

AFAIK, it is not easily possible to do that in C#. The easiest way is to change the Windows settings. On Windows 7:
Go to Control panel
Ease of Access Center
Make the Keyboard easier to use
Check Underline keyboard shortcuts and access keys.