Introduction
Similar Controls
System.Windows.Forms.DateTimePicker
- gTimePicker
How This Control Differs
Features comparison:
| DateTimePicker | gTimePicker | TimeEdit |
Value Update | On Mask complete
On Lost focus
On validated | On Lost focus
On validated | Immediately after key press |
Text and Value is
always the same | No | No | Yes |
Null Value Support | No | Yes | Yes |
could have time only value:
like 0001/01/01 01:00 | No | Yes | Yes |
Has a dropdown clock | No | Yes | In TimeCombo |
It is not needed to use : or arrows
when entering time | No | No | Yes |
Value after key press:
| DateTimePicker | gTimePicker | TimeEdit |
Example displayed Text | 00:00 | 00:00 | 00:00 |
Displayed text after pressing [6] Key | 6:00 | 60:00 | 06:00 |
Value after pressing [6] Key | 00:00 + current date | 00:00 | 06:00 |
Value after lost focus | 06:00 + current date | 06:00 | 06:00 |
Why I Decided to Create It
I need a control that has the following features:
Value
property can be set to time only value such as 00:00 (0001/01/01 00:00) witch is the minimum value for DateTime Type Value
property can be DBNull.Value
and this is useful for database binding - Edit time that always its value reflect the displayed text
- Simple time entering by minimum typing
- Could the increase or decrease its value by mouse weal moving or by arrows pressing
Value Related Property of this Control
Value
(Object): DBNull
or WorkingDayDate
and Time
NullableDateTime
(Nullable(of DateTime
)): Nothing or WorkingDayDate
and Time
NullableTime
(Nullable(of DateTime
)): Nothing or Time
What This Application Does and Why it is Useful
You could include this control in your application to get the following features:
- Allows your application user to enter a time in 24 hour or 12 hour mode
- Protects your application user from entering invalid time
- If your application checks the value of this control, it will always return the right value even before the control lost focus and this is useful to get the value changing as user typing
- You could assign
TimeEdit
control with a WorkingDayDateControl
to return a date and time in a single property - It is a simple control and it is inherits from a
TextBox
and is easy to understand and could be devolved to another more complex control - It is an alternative and more useable than
DateTimePicker
What Problem is Solved
- When user changes the text of
TimeEdit
control, its value changes immediately even if it does not lose focus. TimeEdit
control does not have a MinValue
so it could point to time only value. - It has a
WorkingDayEndTime
and WorkingDayDate
property that is useful when used in appointment arrangement in a working day that continues after midnight - It could be assigned to
WorkingDayDateControl
to get the date part from it and return the date and time in a single Value
property
About TimeCombo and TimeColumn
Globalization
This control will act the same even if your local culture is differ than en-US
. It always uses AM PM and : even if your local culture is use others.
What's the Next Step
- Add a drop down button to display a clock to select time
- Building an appointment grid to arrange appointments that could be continue after mid night without break sorting (00:00 will located after 23:59 when sorting by time
Using the Code
- You could
TimeEdit
control in your Windows application to mentioned time - If you build a user control, you could use
TimeConverter
and DateConverter
for your control property.
The Demo Application
The demo application comparing between DateTimePicker
and TimeEdit
control. There are 2 TimeEdit
controls, the first one has WorkingDayEndTime
property set to 00:00
and the second TimeEdit
control is WorkingDayEndTime
is set to 02:00
. When typing in any TimeEdit
control or in the DateTimePicker
control, the value of the control is shown the date of the second TimeEdit
control is set to 0001/01/02
(yyyy/MM/dd) if the time typed is less that WorkingDayEndTime
and this is useful when sorting time in an appointments arrangements.
It also contains DataGridView
that use TimeColumn
.
Points of Interest
How to Keep Value and Text the Same
To do so, we don't store the value in a separate variable. We use the displayed text to get the value. and when user sets the value programmatically, this control will study the value:
- If new value is numeric, it will be considered as Hour; 6.5 will be converted to 06:30
- If new value is
DateTime
, then the WorkingDayDate
property will be set to the new value date and the NullableTime
property will be set to time part of the new value - If new value is empty
string
, then value will be DBNull
- If new value is
string
that contains time, then the value will return its value
Public Overridable Property Value As Object
Get
Try
If String.IsNullOrEmpty(MyBase.Text) Then
Return DBNull.Value
Else
Return Me.NullableDateAndTime.Value
End If
Catch ex As Exception
ErrMsg(ex)
Return DBNull.Value
End Try
End Get
Set(ByVal NewValue As Object)
Try
If IsNumeric(NewValue) Then
Me.NullableTime = (New Date).AddHours(CDbl(NewValue))
ElseIf IsDate(NewValue) Then
Me.NullableDateAndTime = CDate(NewValue)
ElseIf IsDBNull(NewValue) OrElse NewValue Is Nothing Then
Me.Text = ""
ElseIf GetType(TimeSpan).IsAssignableFrom(NewValue.GetType) Then
Me.NullableTime = New Date(CType(NewValue, TimeSpan).Ticks)
ElseIf GetType(String).IsAssignableFrom(NewValue.GetType) Then
If String.IsNullOrEmpty(CStr(NewValue)) Then
Me.Text = ""
Else
Me.NullableTime = ToDateTime(CStr(NewValue))
End If
Else
Me.Text = ""
End If
Catch ex As Exception
ErrMsg(ex)
End Try
End Set
End Property
Validate Time Input and Protecting User from Entering Invalid Time
- Overrides
Sub OnKeyPress
- If user presses a key in an empty
TimeEdit
control, then it will automatically assign with default value - Build
sText string
that echoes the user input result
Dim sText = Me.Text
Mid(sText, Me.SelectionStart + 1, 1) = e.KeyChar
- Test if the resulting text is valid
Time
using Regular Expressions taking "^(?<Hour>([0-1]\d|2[0-3])):(?<Minute>[0-5]\d)$"
for 24 hour mode and "^(?<Hour>(0?[1-9]|1[0-2])):(?<Minute>[0-5]\d) (?<AMPM>(A|P)M)$"
for 12 hour mode
* This Regular Expressions contains three groups: Hour, Minute and AMPM
* Each group has its rule example Hour in 12 hour mode is 0 followed by any digest or 1 followed by 0-2 - If not match, then study where the editing
char
in hours or in minutes and study its possible fixing as the following code:
Private Sub OnHourKeyPress(ByRef e As KeyPressEventArgs)
Try
Dim Do1 = False
Select Case SelectionStart
Case 0
Select Case e.KeyChar
Case "3"c To "9"c
Do1 = True
Case "2"c
If Not _Hr24 Then
Do1 = True
Else
If Me.Text()(1) > "3"c Then
Mid(Me.Text, 2, 1) = "3"
End If
End If
Case "1"c
If Not _Hr24 Then
If Me.Text()(1) > "2"c Then
Mid(Me.Text, 2, 1) = "2"
End If
End If
End Select
Case 1
Select Case MyBase.Text(0)
Case Is > "2"c
If Not Hr24 Then
Do1 = True
End If
Case "2"c
If Me.Hr24 Then
Select Case e.KeyChar
Case "4"c To "9"c
Do1 = True
End Select
Else
Do1 = True
End If
Case "1"c
If Not _Hr24 Then
Select Case e.KeyChar
Case "3"c To "9"c
Do1 = True
End Select
End If
End Select
End Select
If Do1 Then
Me.Text = "0" & Me.Text.Substring(1)
SelectionStart = 1
SelectionLength = 1
End If
OnTimeKeyPress(e)
Catch ex As Exception
ErrMsg(ex)
End Try
End Sub
TimeEdit
control Inherits TextBox
but it removes some properties by:
- Adding
Designer
attribute:
<ToolboxItem(True), Designer(GetType(TimeEditDesigner)), _
DefaultBindingProperty("Value")> _
Public Class TimeEdit
Inherits TextBox
<DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden), _
Browsable(False), Obsolete("", True)> _
Public Shadows Lines, Multiline, AutoCompleteMode, _
AutoCompleteSource, AutoCompleteCustomSource, WordWrap, _
PasswordChar, UseSystemPasswordChar As DBNull
End Class
- Building
TimeEditDesigner
class:
Imports System.Windows.Forms.Design
Imports System.ComponentModel
Public Class TimeEditDesigner
Inherits ControlDesigner
Protected Overrides Sub PreFilterProperties(ByVal properties As IDictionary)
Try
properties.Remove("PasswordChar")
properties.Remove("UseSystemPasswordChar")
properties.Remove("Text")
properties.Remove("Lines")
properties.Remove("Multiline")
properties.Remove("AutoCompleteMode")
properties.Remove("AutoCompleteSource")
properties.Remove("AutoCompleteCustomSource")
properties.Remove("WordWrap")
MyBase.PreFilterProperties(properties)
Catch ex As Exception
ErrMsg(ex)
End Try
End Sub
Public Overrides ReadOnly Property ActionLists As _
System.ComponentModel.Design.DesignerActionListCollection
Get
Return Nothing
End Get
End Property
Public Overrides ReadOnly Property Verbs As _
System.ComponentModel.Design.DesignerVerbCollection
Get
Return Nothing
End Get
End Property
End Class
How This Application Handles Run Time Errors
Every procedure has the following diagram:
Private Sub OnHourKeyPress(ByRef e As KeyPressEventArgs)
Try
Catch ex As Exception
ErrMsg(ex)
End Try
End Sub
A module that contains ErrMsg
procedure is added to the project to document every run time error that happened in a file located in "C:\Temp".
The error is printed to that file using as follows:
FileOpen(iFile, sLogFileName, OpenMode.Append, OpenAccess.Write)
Print(iFile, vbNewLine & vbNewLine & "Date: " _
& Now.ToString("yyyy/MM/dd HH:mm:ss") & vbNewLine)
Print(iFile, sMsg)
FileClose(iFile)
History
- Initial version
- Adding
TimeCombo
and TimeColumn