- C -


CharLower Function

Declare Function CharLower Lib "user32.dll" Alias "CharLowerA" (ByVal lpsz As String) As String

CharLower converts the letters in a string to their lower-case equivalents. This function has the exact same purpose as Visual Basic's intrinsic LCase function. In fact, LCase is slightly faster and easier to use than CharLower, so use that instead. CharLower is in the API for programming languages that have no intrinsic function to do this. The converted string is returned.
lpszThe string to convert.
Example:
  'Both lines do the same thing.
  Debug.Print LCase$("Hello, world!")
  Debug.Print CharLower("Hello, world!")


Related Call: CharUpper
Category: String Manipulation
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CharUpper Function

Declare Function CharUpper Lib "user32.dll" Alias "CharUpperA" (ByVal lpsz As String) As String

CharUpper converts the letters in a string to their upper-case equivalents. This function has the exact same purpose as Visual Basic's intrinsic UCase function. In fact, UCase is slightly faster and easier to use than CharUpper, so use that instead. CharUpper is in the API for programming languages that have no intrinsic function to do this. The converted string is returned.
lpszThe string to convert.
Example:
  'Both lines do the same thing.
  Debug.Print UCase$("Hello, world!")
  Debug.Print CharUpper("Hello, world!")


Related Call: CharLower
Category: String Manipulation
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ChooseColor Function

Declare Function ChooseColor Lib "comdlg32.dll" Alias "ChooseColorA" (pChoosecolor As CHOOSECOLORS) As Long

ChooseColor displays the choose a color dialog box. While you can use the common dialog custom control to do this, you then have to include the large control file with your programs. This API call is both faster and uses fewer resources. All of the data you pass the function is a part of pChoosecolor, as well as the values chosen. The custom colors of the box are stored in a Byte-sized array in your code, although it must be converted into a Unicode string via the StrConv function before it's passed (see the example for a better idea of how this is done). The function returns 0 if the user chooses Cancel.
pChoosecolorContains all of the arguments passed to the function. Also holds the chosen color and list of custom colors after the function is called.
Example:
  '**Place this code in the (declarations) section of your code.**
  Dim customcolors() As Byte 'dynamic (resizable) array
  '**Place this code in the Form_Load Sub or other similar section.**
  ReDim customcolors(0 To 16 * 4 - 1) As Byte
  Dim i As Integer
  For i = LBound(customcolors) To UBound(customcolors)
    customcolors(i) = 0 'RGB value of a custom color
  Next i
  '**Code to actually create and use the dialog box.**
  Dim cc As CHOOSECOLORS, x As Long
  cc.hwndOwner = Form1.hWnd 'handle of calling form
  cc.lpCustColors = StrConv(customcolors, vbUnicode) 'convert array to string
  cc.flags = CC_ANYCOLOR 'allow any color to be chosen
  cc.lStructSize = Len(cc) 'size of variable
  x = ChooseColor(cc) 'call the dialog box
  If x = 0 Then Exit Sub 'if user chose Cancel
  Form1.BackColor = cc.rgbResult 'set form background to chosen color
  customcolors = StrConv(cc.lpCustColors, vbFromUnicode) 'restore array


Category: Common Dialog
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ClipCursor Function

Declare Function ClipCursor Lib "user32.dll" (lpRect As RECT) As Long

ClipCursor confines the mouse cursor to a rectangular area of the screen. If the mouse starts outside of this rectangle or SetCursorPos tells it to go outside the area, the cursor will immediately be put back in. Nothing can get it out. The cursor will remain in the rectangle no matter what program you switch to, or even if you close the one that confined it. The only way to release it back into full-screen range is to confine it to a rectange the size of the screen (see example). It isn't usually a good idea to confine the cursor, because the user will expect to be able to move the cursor anywhere. The function returns a value which can be safely ignored.
lpRectA RECT variable containing the upper-left and lower-right coordinates of the confinement rectangle.
Example:
  Dim r As RECT
  'This code confines the cursor to inside of Form1
  x = GetWindowRect(Form1.hWnd, r) 'API call puts a window size into a RECT
  x = ClipCursor(r) 'Confine the cursor
  'This code releases the cursor
  deskhWnd = GetDesktopWindow() 'API call gets the handle of the screen window
  x = GetWindowRect(deskhWnd, r) 'API call puts a window size into a RECT
  x = ClipCursor(r) 'Confine the cursor to the entire screen


Related Call: GetClipCursor
Category: Mouse
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CopyRect Function

Declare Function CopyRect Lib "user32.dll" (lpDestRect As RECT, lpSourceRect As RECT) As Long

CopyRect sets one RECT-type variable equal to another. This is done by duplicating all of the member values in the source rectangle to the corresponding values in the target rectangle. While you could do this manually in four commands setting each value equal, this is shorter to write and quicker to understand. You can safely ignore the value returned.
lpDestRectThe RECT to set the member values of.
lpSourceRectThe RECT to set the member values as.
Example:
  'Set RECT target equal to RECT source
  Dim target As RECT, source As RECT
  x = GetWindowRect(Form1.hWnd, source) 'set source to size and shape of Form1
  x = CopyRect(target, source) 'now target.Left = source.Left etc.


Related Call: EqualRect
Category: RECT Manipulation
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