I am having a curious issue with overloading a cell of the DataGridView in VB.NET to use a DateTimePicker (allows user to select both a date and a time). I took the Microsoft implementation of a Calendar picker and modified it be both a Calendar and Time picker. When I enter a new date and press the ENTER key, the displayed date in the DataGridView cell is the old date.
It's only when press ENTER again on that key, or click on that cell and click away that the new value is displayed.
This cell does display the proper date-time value if I click on the cell, enter a new date, and click away onto another cell. Then, the displayed date matches what I inputted. It's using the ENTER key that I am having issues with.
I modified the Microsoft overloaded code as follows:
Public Class TimeColumn
Inherits DataGridViewColumn
Public Sub New()
MyBase.New(New TimeCell())
End Sub
Public Overrides Property CellTemplate() As DataGridViewCell
Get
Return MyBase.CellTemplate
End Get
Set(ByVal value As DataGridViewCell)
' Ensure that the cell used for the template is a TimeCell.
If (value IsNot Nothing) AndAlso _
Not value.GetType().IsAssignableFrom(GetType(TimeCell)) _
Then
Throw New InvalidCastException("Must be a TimeCell")
End If
MyBase.CellTemplate = value
End Set
End Property
End Class
Public Class TimeCell
Inherits DataGridViewTextBoxCell
Public Sub New()
' Use the short date format.
Me.Style.Format = "MM/dd/yy h:mm tt"
'm_isTime = True
End Sub
Public Overrides Sub InitializeEditingControl(ByVal rowIndex As Integer, _
ByVal initialFormattedValue As Object, _
ByVal dataGridViewCellStyle As DataGridViewCellStyle)
' Set the value of the editing control to the current cell value.
MyBase.InitializeEditingControl(rowIndex, initialFormattedValue, _
dataGridViewCellStyle)
Dim ctl As New TimeEditingControl
ctl = CType(DataGridView.EditingControl, TimeEditingControl)
ctl.CustomFormat = "MM/dd/yyyy h:mm tt"
Me.Value = ctl.Value
End Sub
Public Overrides ReadOnly Property EditType() As Type
Get
' Return the type of the editing contol that TimeCell uses.
Return GetType(TimeEditingControl)
End Get
End Property
Public Overrides ReadOnly Property ValueType() As Type
Get
' Return the type of the value that TimeCell contains.
Return GetType(DateTime)
End Get
End Property
Public Overrides ReadOnly Property DefaultNewRowValue() As Object
Get
' Use the current date and time as the default value.
Return DateTime.Now
End Get
End Property
End Class
Class TimeEditingControl
Inherits DateTimePicker
Implements IDataGridViewEditingControl
Private dataGridViewControl As DataGridView
Private valueIsChanged As Boolean = False
Private rowIndexNum As Integer
Public Sub New()
Me.Format = DateTimePickerFormat.Custom
End Sub
Public Property EditingControlFormattedValue() As Object _
Implements IDataGridViewEditingControl.EditingControlFormattedValue
Get
Return Me.Value.ToShortDateString()
End Get
Set(ByVal value As Object)
If TypeOf value Is String Then
Me.Value = DateTime.Parse(CStr(value))
End If
End Set
End Property
Public Function GetEditingControlFormattedValue(ByVal context _
As DataGridViewDataErrorContexts) As Object _
Implements IDataGridViewEditingControl.GetEditingControlFormattedValue
Dim result, tempDateTime As DateTime
tempDateTime = Me.Value
Return tempDateTime.ToString
End Function
Public Sub ApplyCellStyleToEditingControl(ByVal dataGridViewCellStyle As _
DataGridViewCellStyle) _
Implements IDataGridViewEditingControl.ApplyCellStyleToEditingControl
Me.Font = dataGridViewCellStyle.Font
Me.CalendarForeColor = dataGridViewCellStyle.ForeColor
Me.CalendarMonthBackground = dataGridViewCellStyle.BackColor
End Sub
Public Property EditingControlRowIndex() As Integer _
Implements IDataGridViewEditingControl.EditingControlRowIndex
Get
Return rowIndexNum
End Get
Set(ByVal value As Integer)
rowIndexNum = value
End Set
End Property
Public Function EditingControlWantsInputKey(ByVal key As Keys, _
ByVal dataGridViewWantsInputKey As Boolean) As Boolean _
Implements IDataGridViewEditingControl.EditingControlWantsInputKey
Dim lDateTime As DateTime
' Let the DateTimePicker handle the keys listed.
Select key And Keys.KeyCode
Case Keys.Enter
Console.WriteLine(DateTime.Now.ToString & "." & DateTime.Now.Millisecond.ToString & ": EditingControlWantsInputKey--Detected [ENTER] key.")
End Select
valueIsChanged = True
Console.WriteLine("EditingControlWantsInputKey (" & Me.Value & ")")
Dim lDataGridView1 As DataGridView
lDataGridView1 = Me.dataGridViewControl
lDataGridView1.BeginEdit(True)
lDataGridView1.BeginEdit(False)
Return True
End Function
Public Sub PrepareEditingControlForEdit(ByVal selectAll As Boolean) _
Implements IDataGridViewEditingControl.PrepareEditingControlForEdit
' No preparation needs to be done.
End Sub
Public ReadOnly Property RepositionEditingControlOnValueChange() _
As Boolean Implements _
IDataGridViewEditingControl.RepositionEditingControlOnValueChange
Get
Return False
End Get
End Property
Public Property EditingControlDataGridView() As DataGridView _
Implements IDataGridViewEditingControl.EditingControlDataGridView
Get
Return dataGridViewControl
End Get
Set(ByVal value As DataGridView)
dataGridViewControl = value
End Set
End Property
Public Property EditingControlValueChanged() As Boolean _
Implements IDataGridViewEditingControl.EditingControlValueChanged
Get
Return valueIsChanged
End Get
Set(ByVal value As Boolean)
valueIsChanged = value
End Set
End Property
Public ReadOnly Property EditingControlCursor() As Cursor _
Implements IDataGridViewEditingControl.EditingPanelCursor
Get
Return MyBase.Cursor
End Get
End Property
Protected Overrides Sub OnValueChanged(ByVal eventargs As EventArgs)
' Notify the DataGridView that the contents of the cell have changed.
valueIsChanged = True
Me.EditingControlDataGridView.NotifyCurrentCellDirty(True)
MyBase.OnValueChanged(eventargs)
End Sub
End Class
My findings so far:
What's curious is that Public Property EditingControlValueChanged() As Boolean Implements IDataGridViewEditingControl.EditingControlValueChanged does not detect the ENTER key at all! You can see I entered some debugging code for that event to see if it detects the ENTER key being pressed.
The event Public Property EditingControlValueChanged() As Boolean Implements IDataGridViewEditingControl.EditingControlValueChanged does not detect the value change (the boolean valueIsChanged is set to false) until the second time the ENTER key is pressed, at which point it is set to true.
I tried also updating the cell value in the CellEndEdit event for the DataGridView, but that didn't work.
I already updated my Visual Studio Express 2013 in case it was a Micosoft bug.
Any ideas how to get the displayed value to match what was entered upon hitting the ENTER key? Thanks.
My initial comment was definitely wrong. After reproducing your problem, I noticed something funny/frustrating: placing a breakpoint within the EditingControlWantsInputKey method on the following line, allowed the updates to occur as expected (a debugging fix of the problem):
Select key And Keys.KeyCode
That was beyond annoying and in my frustration, I frantically tested month entries in succession: 1, 2, 3, ..., 12
That's when I noticed: months 10-12 updated correctly. In fact, entering 01 updated correctly. My subsequent research led me to the comments section of this article, where user Dean Wiles in his comment titled Changes lost using Tab or Enter provides this Microsoft support source which indicates that:
The ValueChanged event of the [DateTimePicker] is raised only after you type any one of the following:
- All the digits of a year.
- All the digits of a day.
- All the digits of a month.
And this can be addressed by adding the following vb.net version of his code to your TimeEditingControl class:
Protected Overrides Function ProcessCmdKey(ByRef msg As Message, keyData As Keys) As Boolean
Select Case keyData And Keys.KeyCode
Case Keys.Enter, Keys.Tab
Me.dataGridViewControl.Focus()
Exit Select
End Select
Return MyBase.ProcessCmdKey(msg, keyData)
End Function
C# Conversion
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
switch (keyData & Keys.KeyCode)
{
case Keys.Enter:
case Keys.Tab:
this.dataGridView.Focus();
break;
}
return base.ProcessCmdKey(ref msg, keyData);
}
来源：https://stackoverflow.com/questions/31889198/vb-net-update-issue-in-datagridview-cell-for-timepicker-enter-key-does-not-upda