Windows API Guide: CreatePopupMenu Function

Platforms

Windows 95: Supported.
Windows 98: Supported.
Windows NT: Requires Windows NT 3.1 or later.
Windows 2000: Supported.
Windows CE: Requires Windows CE 1.0 or later.

Description & Usage

Sending the EM_LINELENGTH message to an edit control find out how many characters are on a particular line. This message find out the length of one of the control's lines, taking word wrapping into account. However, for some bizarre reason, the line is idenified by a character position and not a line index value.

Return Value

For multi-line edit controls, the message returns the number of characters on the specified line. For single-line edit controls, the message returns the total number of characters in the control.

Visual Basic-Specific Issues

None.

Parameters

wParam: The zero-based index of any character on the line to get the length of. Note that this is a character index, not a line index. (To get the index of the first character on a particular line, send the EM_LINEINDEX message before sending this message.) If this parameter is -1, the function returns the total number of unselected characters that are on lines that contain selected characters.
lParam: Not used -- set to 0.

Constant Definitions

Const EM_LINELENGTH = &HC1

Example

Read the first visible line at the top of edit control Text1. Display the text on that line in the Debug window. This requires sending a series of edit control messages, if we do this via the API. To use this example, place a text edit control named Text1 and a command button named Command1 on a form window. Make sure that the MultiLine property of Text1 is set to True before running the example. To get the first line of text, click button Command1.

' This code is licensed according to the terms and conditions listed here. ' Declarations and such needed for the example: ' (Copy them to the (declarations) section of a module.) Public Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" (Destination As Any, Source _ As Any, ByVal Length As Long) Public Declare Function SendMessage Lib "user32.dll" Alias "SendMessageA" (ByVal hWnd As Long, ByVal _ Msg As Long, wParam As Any, lParam As Any) As Long Public Const EM_GETFIRSTVISIBLELINE = &HCE Public Const EM_GETLINE = &HC4 Public Const EM_LINEINDEX = &HBB Public Const EM_LINELENGTH = &HC1 ' *** Place the following code inside the form window. *** Private Sub Command1_Click() Dim lineindex As Long       ' index of the first visible line Dim charindex As Long       ' index of the first character on that line Dim linetextlen As Integer  ' length of that line (note the data type!) Dim linetext As String      ' receives the line's text Dim retval As Long          ' generic return value ' Get the zero-based index of Text1's first visible line. lineindex = SendMessage(Text1.hWnd, EM_GETFIRSTVISIBLELINE, ByVal CLng(0), ByVal CLng(0)) ' Get the zero-based index of the first character on that line.  This is ' need for the message we'll send next. charindex = SendMessage(Text1.hWnd, EM_LINEINDEX, ByVal lineindex, ByVal CLng(0)) ' Find out the number of characters on that line.  Note how ' we store this in a 16-bit value instead of the regular 32-bit Long. linetextlen = SendMessage(Text1.hWnd, EM_LINELENGTH, ByVal charindex, ByVal CLng(0)) ' Make enough room in the string to receive the text.  However, ' the string must be at least two bytes/characters long for what we'll do next. linetext = Space(IIf(linetextlen>= 2, linetextlen, 2)) ' EM_GETLINE wants the length of the string copied into the first ' two bytes of the string passed to it.  Unusual, but this is the simplest way around ' the two-message-parameter limit.  This is why linetextlen is only 16 bits long. CopyMemory ByVal linetext, linetextlen, Len(linetextlen) ' Finally, read the first line visible in Text1. retval = SendMessage(Text1.hWnd, EM_GETLINE, ByVal lineindex, ByVal linetext) ' In case we made the string too long (if the line was less than two ' characters long), shorten it back up. If linetextlen < 2 Then linetext = Left(linetext, linetextlen) ' Finally, display the text. Debug.Print "The first line visible in Text1 reads: "; linetext End Sub