1、示例環境：VS2010，MFC對話框工程，主要是對話框的OnPaint函數中
CPaintDC dc(this);
CPen pen1(PS_SOLID, 1, RGB(0, 0, 0));
CPen* pOldPen = dc.SelectObject(&pen1);
dc.MoveTo(50, 50);
dc.LineTo(500, 50);
dc.SelectObject(pOldPen);
3、會發現想要繪製粗細大於1的虛線（或是其它非PS_SOLID風格線條）時，繪製出來的都是實線：
<pre name="code" class="cpp"> CPaintDC dc(this);
CPen pen1(PS_DASH, 2, RGB(0, 0, 0));
CPen* pOldPen = dc.SelectObject(&pen1);
dc.MoveTo(50, 50);
dc.LineTo(500, 50);
pen1.DeleteObject();
dc.SelectObject(pOldPen);
4、下面介紹另一種CPen對象的創建方法，以解決上述問題：
（1）對話框OnPaint函數中添加示例代碼：
CPaintDC dc(this);
LOGBRUSH logBrush;
logBrush.lbStyle = BS_SOLID;
logBrush.lbColor = RGB(0, 0, 0);
CPen pen2(PS_DASH | PS_GEOMETRIC | PS_ENDCAP_ROUND, 2, &logBrush);
CPen* pOldPen = dc.SelectObject(&pen2);
dc.MoveTo(50, 50);
dc.LineTo(500, 50);
pen2.DeleteObject();
dc.SelectObject(pOldPen);（2）這樣粗細大於1的虛線就畫出來了：
5、下面是MSDN中的一段相關內容，英文好的話可以讀一讀：
CPen::CreatePen
This method initializes a pen with the specified style, width, and color. The pen can be subsequently selected as the current pen for any device context.
BOOL CreatePen ( int nPenStyle, int nWidth, COLORREF crColor );
Parameters
- nPenStyle
- Specifies the style for the pen. For a list of possible values, see the nPenStyle parameter in the CPen::CPen constructor.
- nWidth
- Specifies the width of the pen.
- For the first version of CreatePen, if this value is zero, the width in device units is always 1 pixel, regardless of the mapping mode.
- For the second version of CreatePen, if nPenStyle is PS_GEOMETRIC, the width is given in logical units. If nPenStyle is PS_COSMETIC, the width must be set to 1.
- crColor
- Contains an RGB color for the pen.
Return Value
Nonzero, or the handle of a logical pen, if successful; otherwise, it is zero.
Remarks
Pens that have a width greater than 1 pixel should always have either the PS_NULL, PS_SOLID, or PS_INSIDEFRAME style.
If a pen has the PS_INSIDEFRAME style and a color that does not match a color in the logical color table, the pen is drawn with a dithered color. The PS_SOLID pen style cannot be used to create a pen with a dithered color. The style PS_INSIDEFRAME is identical to PS_SOLID if the pen width is less than or equal to 1.
The width of a cosmetic pen is always 1; the width of a geometric pen is always specified in world units. After an application creates a logical pen, it can select that pen into a device context by calling the CDC::SelectObject function. After a pen is selected into a device context, it can be used to draw lines and curves.
- If nPenStyle is PS_COSMETIC and PS_USERSTYLE, the entries in the lpStyle array specify lengths of dashes and spaces in style units. A style unit is defined by the device in which the pen is used to draw a line.
- If nPenStyle is PS_GEOMETRIC and PS_USERSTYLE, the entries in the lpStyle array specify lengths of dashes and spaces in logical units.
- If nPenStyle is PS_ALTERNATE, the style unit is ignored and every other pixel is set.
When an application no longer requires a given pen, it should call the CGdiObject::DeleteObject method or destroy the CPen object so the resource is no longer in use. An application should not delete a pen when the pen is selected in a device context.
Windows CE does not support the following overloaded implementation of the CPen::CreatePen method:
BOOL CreatePen( int nPenStyle, int nWidth, const LOGBRUSH* pLogBrush, int nStyleCount = 0, const DWORD* lpStyle = NULL );
In Windows CE version 1.0, only solid pens can draw wide lines.
Example
CPen myPen1, myPen2; // Create a solid red pen of width 2. myPen1.CreatePen(PS_SOLID, 2, RGB(255,0,0)); // Create a geometric pen. LOGBRUSH logBrush; logBrush.lbStyle = BS_SOLID; logBrush.lbColor = RGB(0,255,0); myPen2.CreatePen(PS_DOT|PS_GEOMETRIC|PS_ENDCAP_ROUND, 2, &logBrush);
Requirements
Windows CE versions: 1.0 and later
Header file: Declared in Afxwin.h
Platform: H/PC Pro, Palm-size PC, Pocket PC
6、最後，介紹一些CPen風格，以作備份：
（1）畫筆的樣式：
PS_SOLID -- 實線畫筆
PS_DASH -- 虛線畫筆, 只有當畫筆寬度爲1或更小（以設備單位計算）時纔有效
PS_DOT -- 點線畫筆, 只有當畫筆寬度爲1或更小（以設備單位計算）時纔有效
PS_DASHDOT -- 虛線和點交替, 只有當畫筆寬度爲1或更小（以設備單位計算）時纔有效
PS_DASHDOTDOT -- 創建一支虛線和兩點交替的畫筆。只有當畫筆寬度爲1或更小（以設備單位計算）時纔有效
PS_NULL -- 空畫筆
PS_INSIDEFRAME-- 創建一支畫筆，該畫筆在Windows GDI輸出函數所產生的封閉形狀的框架內畫線，此輸出函數指定一個限定矩形（例如，Ellipse，Rectangle，RoundRect，Pie和Chord成員函數），當此風格用於沒有指定限定矩形的Windows GDI輸出函數（例如LineTo成員函數）時，此畫筆的繪製區域不受框架的限制
PS_GEOMETRIC -- 幾何畫筆
PS_COSMETIC -- 裝飾畫筆
PS_ALTERNATE -- 創建一支交替設置像素的畫筆（此風格只用於裝飾畫筆）
PS_USERSTYLE -- 創建一支使用用戶提供的風格數組的畫筆
（2）筆帽的樣式：
PS_ENDCAP_ROUND -- 尾帽是圓的
PS_ENDCAP_SQUARE -- 尾帽是方的
PS_ENDCAP_FLAT -- 尾帽是平面的(注: 沒有筆帽)
（3）連接的樣式：
PS_JOIN_BEVEL -- 連接是斜截式的
PS_JOIN_MITER -- 當連接在::SetMiterLimit函數所設置的當前限制之內時, 連接是斜接式的. 如果連接超出這個限制則成爲斜截式的
PS_JOIN_ROUND -- 連接是圓的