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NumericUpDown extended control

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Introduction

If you have ever written a data-entry application, there's a big chance you used NumericUpDown control. This control is great to provide a field to enter numeric values, with advanced features like up-down buttons and accelerating auto-repeat.

The other side of the coin is that NumericUpDown is not really mouse-aware. I experienced some bugs and bad behaviors:

  • I need to select all the text when it gets focus (see below), but it misses some of the TextBox properties, like SelectedText, SelectionStart, SelectionLength (an AutoSelect property will be useful).
  • Some of the standard events are not working properly (see below): MouseEnter, MouseLeave.
  • Rotating the mouse wheel when the control is focused causes its value to change. A property to change this behavior, like InterceptArrowsKeys for up/down keys, will be useful.

That's why I decided to subclass it, fixing these points and adding missing features and properties.

Note: this control has been published on CodeProject.

Missing TextBox properties

I needed some missing TextBox properties when I was asked to select all the text in the control when it got the focus.

Yes, NumericUpDown exposes a Select(int Start, int Lenght) method you can call to select all text. At first try, I attached to the GotFocus event to call Select(0, x) but, hey, wait a moment... what should I use for x? It seems that any value is accepted, even if greater than the text length. OK, let's say x=100 and proceed. This works well with the keyboard focus keys (like TAB), but it's completely useless with the mouse: a mouse click raises the GotFocus event (where I select all the text), but as soon as you release the button, a zero-selection is done, leaving the control with no selection. OK, I thought, let's add a SelectAll on the MouseUp event too, but this way, the user cannot perform a partial selection anymore; each time the mouse button is released, all the text is selected. I need to know if a partial selection exists; in a TextBox, I can test it with SelectionLength > 0, so I need to access the underlying TextBox control.

Now comes the tricky part: NumericUpDown is a composite control, a TextBox and a button box. Looking inside it through the Reflector, we can find the internal field which holds the textbox part:

Friend upDownEdit As UpDownEdit  ' UpDownEdit inherits from TextBox

We'll obtain a reference to this field using the underlying Controls() collection. Note that we should add some safety checks because .NET guys could change things in the future.

''' <summary>
''' object creator
''' </summary>
Public Sub New()
&nbsp;&nbsp;&nbsp; MyBase.New()
&nbsp;&nbsp;&nbsp; ' get a reference to the underlying UpDownButtons field
&nbsp;&nbsp;&nbsp; ' Underlying private type is System.Windows.Forms.UpDownBase+UpDownButtons
&nbsp;&nbsp;&nbsp; _upDownButtons = MyBase.Controls(0)
&nbsp;&nbsp;&nbsp; If _upDownButtons Is Nothing _
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; OrElse _upDownButtons.GetType().FullName <> "System.Windows.Forms.UpDownBase+UpDownButtons" Then
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Throw New ArgumentNullException(Me.GetType.FullName & ": Can't a reference to internal UpDown buttons field.")
&nbsp;&nbsp;&nbsp; End If
&nbsp;&nbsp;&nbsp; ' Get a reference to the underlying TextBox field.
&nbsp;&nbsp;&nbsp; ' Underlying private type is System.Windows.Forms.UpDownBase+UpDownButtons
&nbsp;&nbsp;&nbsp; _textbox = TryCast(MyBase.Controls(1), TextBox)
&nbsp;&nbsp;&nbsp; If _textbox Is Nothing _
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; OrElse _textbox.GetType().FullName <> "System.Windows.Forms.UpDownBase+UpDownEdit" Then
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Throw New ArgumentNullException(Me.GetType.FullName & ": Can't get a reference to internal TextBox field.")
&nbsp;&nbsp;&nbsp; End If
End Sub 

Now that we have the underlying TextBox, it is possible to export some missing properties:

<browsable(false)> _
<designerserializationvisibility( _=""> _
Public Property SelectionStart() As Integer
    Get
        Return _textbox.SelectionStart
    End Get
    Set(ByVal value As Integer)
        _textbox.SelectionStart = value
    End Set
End Property</designerserializationvisibility(></browsable(false)>

And finally, we can have a perfectly working mouse management:

' MouseUp will kill the SelectAll made on GotFocus.
' Will restore it, but only if user have not made
' a partial text selection.
Protected Overrides Sub OnMouseUp(ByVal mevent As MouseEventArgs)
    If _autoSelect AndAlso _textbox.SelectionLength = 0 Then
        _textbox.SelectAll()
    End If
    MyBase.OnMouseUp(mevent)
End Sub

Mouse events not raised properly

The original MouseEnter and MouseLeave events are raised in couples: a MouseEnter immediately followed by a MouseLeave. Maybe that's why, to discourage their use, they are marked with a <browsable(false)> attribute. Since I need the MouseEnter event to update my StatusBar caption, I investigated a little on this "bug".

As said above, NumericUpDown is a composite control (red rectangle in the following picture) containing a TextBox (left green rectangle) and some other controls:

The "control" area is the one between the red and the green rectangles; when you fly over it with the mouse, you'll receive the MouseEnter event while between the red and the green, then MouseLeave when inside the green rectangle. The same happens when you leave.

The better way to raise these events, now that we can access the underlying TextBox, is to re-raise the MouseEnter and MouseLeave events as raised from the TextBox itself; this is what NumericUpDownEx does.

MouseWheel management

NumericUpDown's management of the mouse wheel is, sometimes, really annoying. Suppose you have an application which displays some kind of chart, with a topmost dialog (toolbox) to let the user change some parameters of the graph. In this dialog, the only controls which can keep the focus are NumericUpDown ones:

After your user puts the focus inside one of them, the mouse wheel is captured by the NumericUpDown. When the user wheels to, say, scroll the graph, the effect is that the focused field value is changed; this behavior is really annoying.

A fix could be to kill the WM_MOUSEWHEEL message for the control, but this will kill even "legal" wheelings.

The NumericUpDown has a property which allows WM_MOUSEWHEEL messages to pass only if the mouse pointer is over the control, making sure that the user is wheeling to change the control value.

This is done by keeping track of the mouse state in the MouseEnter-MouseLeave events, then killing WM_MOUSEWHEEL messages accordingly.

Up-Down buttons visibility

You can hide Up and Down buttons box when the mouse is not over the control.
To achieve this, set the ShowUpDownButtons property to WhenMouseOver instead of Always.

How to use the control

Simply compile sources and include NumericUpDownEx.vb in your project, using the control like you'll do with the standard NumericUpDown.
You could also directly include its source code into your project, avoiding the deployment of an additional DLL.

Version history 

v1.5 (28/Mar/2014)

  • Removed reflection code, now underlying controls are retrieved with managed code only (thanks to JWhattam for this suggestion).

v1.4 - 2012-12-17

  • New option to show up/down buttons when the control has focus (regardless of mouseover), thanks to Fred Kreppert for his suggestion.

v1.3 - 2010-03-15

  • Added new property: when set, if Maximum is reached during an increment, Value will restart from Minimum (and vice versa)
    (feature suggested by YosiHakel here)
  • Cleaned up the C# version

v1.2 - 2010-02-10

  • Added two new events BeforeValueDecrement and BeforeValueIncrement, as suggested by andrea@gmi.
    This will allow to give different increment/decrement depending on current control value
  • Added a C# version of the control to the ZIP

Download

NumericUpDownEx_1.5_src.zip
Release date 2014-Mar-28 Size 33,494 bytes
MD5 c10dc67eea7d4d658e797423e45cf229
SHA1 0af4044c5929025e0e61962b3da0d59b1811ff01
SHA256 27717ff6508ac00ef50cfa7f45f0304fd68407f5ba39fe110a8c89b388adaf02

Comments

Thanks for C# code (I was looking for a wrapping solution).

Here some additional suggestions:

1) Double click on up/down to set Maximum/Minimum

2) Support for units. Let's say you are defining a base unit string like 'inch'. And additional units strings with a factor like 'cm' + 1/2.54. The value would always be returned in the base unit. Means if the user enters one of the additional units the value in the text box will be multiplied with the factor and set as value.

cu Martin

 

 

Your suggestion sounds good; could you provide a patch?
If yes I'll include it to next version.

You could also throw the same idea on CodeProject...

Sorry no, I was hoping you could. At least for the double-click. But here is a patch for wrapping which respects the increment.

public enum WrapMode { None, MaxToMin, UseIncrement }
private WrapMode _wrap = WrapMode.None;
 
public WrapMode Wrap {
    get {
        return _wrap;
    }
    set {
        _wrap = value;
    }
}
 
public override void UpButton() {
    if (base.ReadOnly) return;
    switch (_wrap) {
    case WrapMode.None:
        break;
    case WrapMode.MaxToMin:
        if (Value + Increment > Maximum) { Value = Minimum; return; }
        break;
    case WrapMode.UseIncrement:
        if (Value + Increment > Maximum) {
            Value = Minimum + (Value + Increment - Maximum);
            return;
        }
        break;
    }
    base.UpButton();
}
 
public override void DownButton() {
    if (base.ReadOnly) return;
    switch (_wrap) {
    case WrapMode.None:
        break;
    case WrapMode.MaxToMin:
        if (Value - Increment < Minimum) {
            Value = Maximum;
            return;
        }
        break;
    case WrapMode.UseIncrement:
        if (Value - Increment < Minimum) {
            Value = Maximum + (Value - Increment - Minimum);
            return;
        }
        break;
    }
    base.DownButton();
}

 

Thanks for your patch, I'll add it to next version.

Protected Overrides Sub OnValidating(e As System.ComponentModel.CancelEventArgs)
  If Not Me.ReadOnly Then
    MyBase.OnValidating(e) 
  End If 
End Sub

Thanks for your suggestion, I'll add it to next release.

This is a great control!

Do you have in your plan to add same enhancements to the datetimepicker control?

I find it quite uncomfortable. 

Maax

No, I'm not.

Anyway you can have a look to these links I found for another project of mine:

Hope you find them useful.