there is precious little to one of these until you want to do like VS and present System Colors apart from Named Colors, make it a popup or some such. Example using colors as the BackGround:
' capture the names
Private _Colors As String()
' get the names
' add qualifiers to skip SystemCOlors or
' Transparent as needed
Function GetColorNames As String()
For Each colorName As String In KnownColor.GetNames(GetType(KnownColor))
_Colors.Add(colorName)
End If
Next
' post the names to a CBO:
cboBackColor.Items.AddRange(_Colors)
On the form CBO, set the DrawMode to OwnerDrawFixed
, then:
Private Sub cboSheetBackColor_DrawItem(ByVal sender As Object,
ByVal e As System.Windows.Forms.DrawItemEventArgs)
Handles cboSheetBackColor.DrawItem
Dim Bclr As Color, Fclr As Color
' get the colors to use for this item for this
Bclr = Color.FromName(_Colors(e.Index).ToString)
Fclr = GetContrastingColor(Bclr) ' see below
With e.Graphics
Using br As New SolidBrush(Bclr)
.FillRectangle(br, e.Bounds)
End Using
Using br As New SolidBrush(Fclr)
.DrawString(cboSheetBackColor.Items(e.Index).ToString,
cboSheetBackColor.Font, br,
e.Bounds.X, e.Bounds.Y)
End Using
End With
e.DrawFocusRectangle()
End Sub
You can just draw a swatch like Windows/VS does by defining a rectangle to fill. Generally, thats swell, but in the case where you are doing something like defining a background color it rather helps to show how it looks with text on it and more of the color than the little bitty swatch - hence the filled CBO Item rect.
The standard window Text color will not show up on all of them. For a "light" theme, Violet and Black etc will hide/make the color name impossible to read. GetContrastingColor
is a function which evaluates the Brightness of the current color and then returns either White or Black:
Public Function GetContrastingColor(ByVal clrBase As Color) As Color
' Y is the "brightness"
Dim Y As Double = (0.299 * clrBase.R) _
+ (0.587 * clrBase.G) _
+ (0.114 * clrBase.B)
If (Y < 140) Then
Return Color.White
Else
Return Color.Black
End If
End Function
You can then use all this in a Class which inherits from ComboBox, or build a UserControlif you like distinct controls. You can also leave it as code in a DLL which is called on those occasions. I should mention there are also perhaps a dozen such critters on CodeProject.