Disable items in Combobox

[Kevinp]

I've spent the last four hours Google searching for a way to disable
items in a Combobox. I found one example in C++ which I can't get to
work and another in C# that I couldn't get to work either.

Does anyone have some good code for an owner-drawn combobox?

[cfps.Christian]

Re: Disable items in Combobox

This would be a tough one to hack. You can make a lineitem user
control that can be disabled at will and handles the selection code.
The line item held within another usercontrol that has some kind of
dynamic sizing to handle adding of multiple line items. Me personally
the best way I've found to lock down an item in a drop down is to
remove it.

[Kevinp]

Re: Disable items in Combobox

On Wed, 30 Jul 2008 12:10:27 -0400, Kevinp
<kmahoney@nospa m_fireacademy.o rgwrote:

>I've spent the last four hours Google searching for a way to disable
>items in a Combobox. I found one example in C++ which I can't get to
>work and another in C# that I couldn't get to work either.
>
>Does anyone have some good code for an owner-drawn combobox?

I've already got a custom combobox control that I copied from someone
else and made the changes that I needed.

What I can't figure out is how to add a property to an item in the
combobox.

Like this: cboMyCombo.Item s(2).Enabled = False

I know how to make a property for the Combobox, but not for an item in
the Combobox. Can anyone help me?

[SuNcO]

Re: Disable items in Combobox

What about a trick.. You can set on an Array what index want to "disable".
On the SelectedIndexCh anged event you can check if that option is in the
Array and then do a SelectedIndex = 0 (or the last one selected)

Many stuff is just simply tricks (like this)

Hope this help

--
Windows Live Butterfly
My little blog - http://sunco.codigoplus.com (in Spanish)

"Kevinp" <kmahoney@nospa m_fireacademy.o rgescribió en el mensaje de
noticias:oit694 50c7e9ckalss8ib r4qi8p9f2au5i@4 ax.com...

On Wed, 30 Jul 2008 12:10:27 -0400, Kevinp
<kmahoney@nospa m_fireacademy.o rgwrote:
>

>>I've spent the last four hours Google searching for a way to disable
>>items in a Combobox. I found one example in C++ which I can't get to
>>work and another in C# that I couldn't get to work either.
>>
>>Does anyone have some good code for an owner-drawn combobox?

>
>
I've already got a custom combobox control that I copied from someone
else and made the changes that I needed.
>
What I can't figure out is how to add a property to an item in the
combobox.
>
Like this: cboMyCombo.Item s(2).Enabled = False
>
I know how to make a property for the Combobox, but not for an item in
the Combobox. Can anyone help me?

[Martin H.]

Re: Disable items in Combobox

Hello Kevin,

the following code will have a quick hack version of what you need.
Just create a form and add the following code. Then, compile the project.

Now, add one "EnableItemComb oBox" and a button. Copy the Form1 code into
that form.

Run the program and click the button. Then, open the list of the
ComboBox. The "Disabled" entry will be in the color your Windows
settings define for DisabledCaption (Default: light gray).

Best regards,

Martin

Public Class EnableItemCombo Box
Inherits ComboBox

Private vDisabledItems As New Collection

Public Property DisabledItems(B yVal Index As Integer) As Boolean
Get
Dim retVal As Boolean
If vDisabledItems. Contains("Key" & CStr(Index)) Then
retVal = CBool(vDisabled Items("Key" & CStr(Index)))
Else
retVal = False
End If
Return retVal
End Get
Set(ByVal value As Boolean)
If vDisabledItems. Contains("Key" & CStr(Index)) Then
vDisabledItems. Remove("Key" & CStr(Index))
End If

If value = True Then
vDisabledItems. Add("-1", "Key" & CStr(Index))
End If
End Set
End Property

Private Sub EnableItemCombo Box_DrawItem(By Val sender As Object, ByVal e
As System.Windows. Forms.DrawItemE ventArgs) Handles Me.DrawItem
Dim Pn As Pen
If DisabledItems(e .Index) = False Then
Pn = New Pen(Color.FromK nownColor(Known Color.WindowTex t))
Else
Pn = New Pen(Color.FromK nownColor(Known Color.InactiveC aptionText))
End If

Dim Br As Brush = Pn.Brush
e.DrawBackgroun d()
e.DrawFocusRect angle()
e.Graphics.Draw String(Me.Items (e.Index).ToStr ing, e.Font, Br,
e.Bounds.X, e.Bounds.Y)
End Sub

Private Sub EnableItemCombo Box_SelectedInd exChanged(ByVal sender As
Object, ByVal e As System.EventArg s) Handles Me.SelectedInde xChanged
If DisabledItems(M e.SelectedIndex ) = True Then
Dim NewIndex As Integer = FindEnabledInde x(Me.SelectedIn dex, True)
If NewIndex = -1 Then
NewIndex = FindEnabledInde x(Me.SelectedIn dex, False)
End If

If NewIndex -1 Then
Me.SelectedInde x = NewIndex
Beep()
End If
End If
End Sub

Private Function FindEnabledInde x(ByVal StartValue As Integer, ByVal
Descending As Boolean) As Integer
Dim EndValue As Integer
Dim Steps As Integer
Dim t As Integer
Dim retValue As Integer = -1

If Descending = True Then
StartValue = Items.Count - 1
EndValue = 0
Steps = -1
Else
StartValue = 0
EndValue = Items.Count - 1
Steps = 1
End If

For t = StartValue To EndValue Step Steps
If DisabledItems(t ) = False Then
retValue = t
Exit For
End If
Next

Return retValue
End Function
End Class



Public Class Form1

Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As _
System.EventArg s) Handles Button1.Click
EnableItemCombo Box1.Items.Add( "Enabled")
EnableItemCombo Box1.Items.Add( "Disabled")
EnableItemCombo Box1.DisabledIt ems(1) = True
EnableItemCombo Box1.DrawMode = DrawMode.OwnerD rawFixed
End Sub
End Class


On 02.08.2008 04:49, Kevinp wrote:

On Wed, 30 Jul 2008 12:10:27 -0400, Kevinp
<kmahoney@nospa m_fireacademy.o rg wrote:
>

>I've spent the last four hours Google searching for a way to disable
>items in a Combobox. I found one example in C++ which I can't get to
>work and another in C# that I couldn't get to work either.
>>
>Does anyone have some good code for an owner-drawn combobox?

>
>
I've already got a custom combobox control that I copied from someone
else and made the changes that I needed.
>
What I can't figure out is how to add a property to an item in the
combobox.
>
Like this: cboMyCombo.Item s(2).Enabled = False
>
I know how to make a property for the Combobox, but not for an item in
the Combobox. Can anyone help me?

[Kevinp]

Re: Disable items in Combobox

Thanks Martin. Exactly what I needed. I did make one change though. I
added this to the class:

Public Sub New()
Me.DrawMode = Windows.Forms.D rawMode.OwnerDr awFixed
End Sub

....instead of adding it to every form I use the new control on. No
biggee--just saves a little work.

Thanks,
Kevin

On Mon, 04 Aug 2008 13:30:16 +0800, "Martin H." <hkshk@gmx.netw rote:

>Hello Kevin,
>
>the following code will have a quick hack version of what you need.
>Just create a form and add the following code. Then, compile the project.
>
>Now, add one "EnableItemComb oBox" and a button. Copy the Form1 code into
>that form.
>
>Run the program and click the button. Then, open the list of the
>ComboBox. The "Disabled" entry will be in the color your Windows
>settings define for DisabledCaption (Default: light gray).
>
>Best regards,
>
>Martin
>
>Public Class EnableItemCombo Box
>Inherits ComboBox
>
>Private vDisabledItems As New Collection
>
>Public Property DisabledItems(B yVal Index As Integer) As Boolean
> Get
> Dim retVal As Boolean
> If vDisabledItems. Contains("Key" & CStr(Index)) Then
> retVal = CBool(vDisabled Items("Key" & CStr(Index)))
> Else
> retVal = False
> End If
> Return retVal
> End Get
> Set(ByVal value As Boolean)
> If vDisabledItems. Contains("Key" & CStr(Index)) Then
> vDisabledItems. Remove("Key" & CStr(Index))
> End If
>
> If value = True Then
> vDisabledItems. Add("-1", "Key" & CStr(Index))
> End If
> End Set
>End Property
>
>Private Sub EnableItemCombo Box_DrawItem(By Val sender As Object, ByVal e
>As System.Windows. Forms.DrawItemE ventArgs) Handles Me.DrawItem
>Dim Pn As Pen
> If DisabledItems(e .Index) = False Then
> Pn = New Pen(Color.FromK nownColor(Known Color.WindowTex t))
> Else
> Pn = New Pen(Color.FromK nownColor(Known Color.InactiveC aptionText))
> End If
>
>Dim Br As Brush = Pn.Brush
>e.DrawBackgrou nd()
>e.DrawFocusRec tangle()
>e.Graphics.Dra wString(Me.Item s(e.Index).ToSt ring, e.Font, Br,
>e.Bounds.X, e.Bounds.Y)
>End Sub
>
>Private Sub EnableItemCombo Box_SelectedInd exChanged(ByVal sender As
>Object, ByVal e As System.EventArg s) Handles Me.SelectedInde xChanged
> If DisabledItems(M e.SelectedIndex ) = True Then
> Dim NewIndex As Integer = FindEnabledInde x(Me.SelectedIn dex, True)
> If NewIndex = -1 Then
> NewIndex = FindEnabledInde x(Me.SelectedIn dex, False)
> End If
>
> If NewIndex -1 Then
> Me.SelectedInde x = NewIndex
> Beep()
> End If
> End If
>End Sub
>
>Private Function FindEnabledInde x(ByVal StartValue As Integer, ByVal
>Descending As Boolean) As Integer
>Dim EndValue As Integer
>Dim Steps As Integer
>Dim t As Integer
>Dim retValue As Integer = -1
>
> If Descending = True Then
> StartValue = Items.Count - 1
> EndValue = 0
> Steps = -1
> Else
> StartValue = 0
> EndValue = Items.Count - 1
> Steps = 1
> End If
>
> For t = StartValue To EndValue Step Steps
> If DisabledItems(t ) = False Then
> retValue = t
> Exit For
> End If
> Next
>
>Return retValue
>End Function
>End Class
>
>
>
>Public Class Form1
>
>Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As _
>System.EventAr gs) Handles Button1.Click
>EnableItemComb oBox1.Items.Add ("Enabled")
>EnableItemComb oBox1.Items.Add ("Disabled")
>EnableItemComb oBox1.DisabledI tems(1) = True
>EnableItemComb oBox1.DrawMode = DrawMode.OwnerD rawFixed
>End Sub
>End Class
>
>
>On 02.08.2008 04:49, Kevinp wrote:

>On Wed, 30 Jul 2008 12:10:27 -0400, Kevinp
><kmahoney@nosp am_fireacademy. org wrote:
>>

>>I've spent the last four hours Google searching for a way to disable
>>items in a Combobox. I found one example in C++ which I can't get to
>>work and another in C# that I couldn't get to work either.
>>>
>>Does anyone have some good code for an owner-drawn combobox?

>>
>>
>I've already got a custom combobox control that I copied from someone
>else and made the changes that I needed.
>>
>What I can't figure out is how to add a property to an item in the
>combobox.
>>
>Like this: cboMyCombo.Item s(2).Enabled = False
>>
>I know how to make a property for the Combobox, but not for an item in
>the Combobox. Can anyone help me?