How To Use Color Dialog from COMDLG32.DLL in VB and Access

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Article ID: 153929 - View products that this article applies to.
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SUMMARY

Making use of the COMDLG32.DLL is a good reuse of resources under Windows because Windows always has COMDLG32.DLL loaded. If you use the COMDLG32.OCX control instead, your program must load the OCX into memory and you must also distribute an additional 90K file to your customers. The OCX control provides an easy-to-use interface to predefined dialog boxes, but is a more expensive hit on performance and resources. To optimize performance and reduce resource usage, you should minimize the use of controls in your applications and use the Win32 API calls directly. Below is a code sample of how to use the Choose Color dialog box in the COMDLG32.DLL.

MORE INFORMATION

1a. Visual Basic: Start a new project. Form1 is created by default.

1b. Access: Open a database and create a new form.
  1. Add a CommandButton (Command1) to the form.
  2. Add the following code to the General Declarations section of the form:
       Option Explicit
    
       Private Type CHOOSECOLOR
         lStructSize As Long
         hwndOwner As Long
         hInstance As Long
         rgbResult As Long
         lpCustColors As String
         flags As Long
         lCustData As Long
         lpfnHook As Long
         lpTemplateName As String
       End Type
    
       Private Declare Function ChooseColorAPI Lib "comdlg32.dll" Alias _
         "ChooseColorA" (pChoosecolor As CHOOSECOLOR) As Long
    
       Dim CustomColors() As Byte
    
       Private Sub Command1_Click()
           Dim cc As CHOOSECOLOR
           Dim Custcolor(16) As Long
           Dim lReturn As Long
           cc.lStructSize = Len(cc)
           cc.hwndOwner = Me.hWnd
           cc.hInstance = 0
           cc.lpCustColors = StrConv(CustomColors, vbUnicode)
           cc.flags = 0
           lReturn = ChooseColorAPI(cc)
           If lReturn <> 0 Then
               Me.Caption = "RGB Value User Chose: " & Str$(cc.rgbResult)
               Me.BackColor = cc.rgbResult            ' Visual Basic only ****
               Me.Section(0).BackColor = cc.rgbResult ' Access only **********
               CustomColors = StrConv(cc.lpCustColors, vbFromUnicode)
           Else
               MsgBox "User chose the Cancel Button"
           End If
       End Sub
    
       Private Sub Form_Load()
           ReDim CustomColors(0 To 16 * 4 - 1) As Byte
           Dim i As Integer
    
           For i = LBound(CustomColors) To UBound(CustomColors)
               CustomColors(i) = 0
           Next i
       End Sub
    
    					
4a. Visual Basic: Press the F5 key to run the project.

4b. Access: Use the View|Form menu to open the form and run it.
  1. Click the CommandButton and the Color dialog box will be displayed. When you choose a color and press OK, the background color of the form will change to your selected color.
The constant CC_PREVENTFULLOPEN, with a decimal value of 4, can be used in the flags element of the CHOOSECOLOR structure if you wish to prevent the Custom Colors part of the Dialog from being displayed.

NOTE: In the Command1_Click routine above, the code to set the background color of an Access form and a Visual Basic form is slightly different. Both commands are included and commented. Only type the command that is appropriate for the product you are using.

REFERENCES

Microsoft Visual Basic Programmer's Guide, Chapter 11, P.325-332.

Win32 SDK.

Properties

Article ID: 153929 - Last Review: July 13, 2004 - Revision: 2.1
APPLIES TO
  • Microsoft Visual Basic 5.0 Professional Edition
  • Microsoft Visual Basic 6.0 Professional Edition
  • Microsoft Visual Basic 5.0 Enterprise Edition
  • Microsoft Visual Basic 6.0 Enterprise Edition
  • Microsoft Visual Basic 4.0 Standard Edition
  • Microsoft Visual Basic 4.0 Professional Edition
  • Microsoft Visual Basic 4.0 32-Bit Enterprise Edition
Keywords: 
kbhowto KB153929

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