📄 windows api函数使用技巧i.htm
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另一个component VersionInfo.zip<br> </td> </tr> <tr> <td><font color="0000FF"><a name="16">防止程序运行多个例程? </a></font></td> </tr> <tr> <td>More than one instance of program?<br> 回答<br> This is copied direct from my *.dpr file. You can work it for your own<br> use.<br> var<br> hMutex : Thandle;<br> WaitResult : word;<br> BroadcastList : DWORD;<br> begin<br> MessageID := RegisterWindowMessage('Check For Choice Previous Inst');<br> // register a message to use later on<br> hMutex := createMutex(nil,false,pchar('App_Choice')); // grab a mutex<br> handle<br> WaitResult := WaitForSingleObject(hMutex,10); // wait to see<br> if we can have exclusive use of the mutex<br> if ( waitResult = WAIT_TIMEOUT ) then // if we can't then broadcast<br> the message to make the owner of the mutex respond<br> { request that the running application takes focus }<br> begin<br> BroadcastList := BSM_APPLICATIONS;<br> BroadcastSystemMessage(<br> BSF_POSTMESSAGE,@BroadcastList,MessageID,0,0); //32 bit - broadcast the<br> message to all apps - only a prev inst will hear it.<br> end<br> else<br> begin<br> { do the normal stuff}<br> Application.Title := 'Choice Organics Purchase & Sales System';<br> Application.CreateForm(TMainForm, MainForm);<br> Application.Run;<br> ReleaseMutex(hMutex); // release the mutex as a politeness<br> end;<br> CloseHandle(hMutex); // close the mutex handle<br> end.<br> This goes in the MainForm<br> procedure Tmainform.OnAppMessage(var Msg : TMsg ; Var Handled : Boolean);<br> begin<br> { If it's the special message then focus on this window}<br> if Msg.Message = MessageID then // if we get the broadcast message from an<br> another instance of this app that is trying to start up<br> begin<br> show;<br> WindowState := wsMaximized;<br> BringToFront;<br> SetFocus;<br> Handled := true;<br> end;<br> end;<br> //And this goes in the TMainForm.FormCreate ;-<br> Application.OnMessage:= OnAppMessage;<br> </td> </tr> <tr> <td><font color="0000FF"><a name="17">4.得到Win 95 的计算机名字? </a></font></td> </tr> <tr> <td>问 How can I learn Windows'95 Machine Name?<br> 答function ComputerName : String;<br> var<br> CNameBuffer : PChar;<br> fl_loaded : Boolean;<br> CLen : ^DWord;<br> begin<br> GetMem(CNameBuffer,255);<br> New(CLen);<br> CLen^:= 255;<br> fl_loaded := GetComputerName(CNameBuffer,CLen^);<br> if fl_loaded then<br> ComputerName := StrPas(CNameBuffer)<br> else<br> ComputerName := 'Unkown';<br> FreeMem(CNameBuffer,255);<br> Dispose(CLen);<br> end;<br> </td> </tr> <tr> <td><font color="0000FF"><a name="18">7. 停止一个线程？ </a></font></td> </tr> <tr> <td>问 Stop A Thread?<br> 回答<br> You can Terminate your thread in two ways:<br> 1) Assign ThreadDone to OnTerminate when you create it.<br> In the Execute method, exit when the terminated property is True.<br> At the point where you want to stop, issue the Terminate method.<br> 2) Just call the Suspend method.<br> After one of these steps you may free the thread.<br> I hope the following snippets will help.<br> // -------------------------------------------------------------- //<br> interface<br> type<br> Txyz = class(TThread)<br> published<br> procedure Execute; override;<br> end;<br> var<br> XYZThread: Txyz;<br> implementation<br> procedure Txyz.Execute;<br> begin<br> while True do Application.ProcessMessages;<br> end;<br> procedure TForm1.Button1Click(Sender: TObject);<br> begin<br> XYZThread := Txyz.Create(False);<br> end;<br> procedure TForm1.Button2Click(Sender: TObject);<br> begin<br> XYZThread2.Suspend;<br> XYZThread2.Free;<br> end;<br> end.<br> </td> </tr> <tr> <td><font color="0000FF"><a name="19">如何在WINDOWS中象在UCDOS下控制打印字体的长宽，而不受限于SIZE 的限制。</a></font></td> </tr> <tr> <td>首先为了达到这个功能，可以采用Windows的逻辑字体(LogFont)<br> 可以使用 CreateFont 或 CreateFontIndirect 这两个Windows API<br> 函数来定义任何想要的字体，由于 CreateFont 所需的参数甚多通常<br> 我们使用 CreateFontIndirect 来建立所需的逻辑字体，这个API函数<br> 在Delphi中的声明为<br> function CreateFontIndirect(const p1: TLogFont): HFONT; stdcall;<br> 其中只有一个参数 p1: TLogfont, 所有有关字体的参数完全通过这个<br> TLogfont结构来传送，Windows将根据结构中的内容创建出相应的逻辑<br> 字体，在Delphi的Windows.pas中TLogFont是这样定义的<br> TLogFontA = packed record<br> lfHeight: Longint;<br> lfWidth: Longint;<br> lfEscapement: Longint;<br> lfOrientation: Longint;<br> lfWeight: Longint;<br> lfItalic: Byte;<br> lfUnderline: Byte;<br> lfStrikeOut: Byte;<br> lfCharSet: Byte;<br> lfOutPrecision: Byte;<br> lfClipPrecision: Byte;<br> lfQuality: Byte;<br> lfPitchAndFamily: Byte;<br> lfFaceName: array[0..LF_FACESIZE - 1] of AnsiChar;<br> end;<br> TLogFontW = packed record<br> lfHeight: Longint;<br> lfWidth: Longint;<br> lfEscapement: Longint;<br> lfOrientation: Longint;<br> lfWeight: Longint;<br> lfItalic: Byte;<br> lfUnderline: Byte;<br> lfStrikeOut: Byte;<br> lfCharSet: Byte;<br> lfOutPrecision: Byte;<br> lfClipPrecision: Byte;<br> lfQuality: Byte;<br> lfPitchAndFamily: Byte;<br> lfFaceName: array[0..LF_FACESIZE - 1] of WideChar;<br> end;<br> TLogFont = TLogFontA;<br> 其中涉及到很多参数，其中<br> lfHeight: Longint;<br> 指定以逻辑单位标定的字体高度，取值可为正负或零，对于需要随意<br> 定义字体高度的情况下通常取负值，以保证获得实际尺寸的字体。<br> lfWidth: Longint;<br> 用于指定字体的平均宽度，由于Windows系统下的大多数字体都是比例<br> 字体因而采用平均宽度这个表示方法。若指定为0，则系统会自动根据<br> 适当的比例自动处理宽度。<br> lfEscapement: Longint;<br> 指定输出方向与当前坐标系X轴之间的以十分之一度为单位的角度。<br> lfOrientation: Longint;<br> 指定每个字符与当前坐标系X轴之间的以十分之一度为单位的角度。在<br> Windows95中这个值等同于lfEscpement。<br> lfWeight: Longint;<br> 指定范围为从0至1000的字体加重程度，400是标准字体700为加重字体，<br> 0表示采用默认值。<br> lfItalic: Byte;<br> 不为0表示采用斜体字。<br> lfUnderline: Byte;<br> 不为0表示带下划线。<br> lfStrikeOut: Byte;<br> 不为0表示带穿透线。<br> lfCharSet: Byte;<br> 指定字体集。<br> lfOutPrecision: Byte;<br> 指定输出精度。用于确定对前面一些设定值的精确程度。<br> lfClipPrecision: Byte;<br> 指定裁剪精度。裁剪是Windows图形环境下的一种特殊处理，简单说就是<br> 去掉图形中落在视图以外的部分，有助于提高图形的处理速度。<br> lfQuality: Byte;<br> 指定输出质量。<br> lfPitchAndFamily: Byte;<br> 指定字体的Pitch和Family。<br> lfFaceName: array[0..LF_FACESIZE - 1] of AnsiChar;<br> 指定采用的字体名称。<br> 在建立逻辑字体时，我们通常使用<br> lfHeight和lfWidth来确定字体的尺寸，使用lfEscapement和lfOrientation<br> 来确定字体的输出方向，使用lfWeight, lfItalic, lfUnderline,<br> lfStrikeOut, 来确定字体的加重，斜体，下划线和穿透线，使用lfCharSet<br> 来确定字体的字符集，通常采用系统默认的字符集。<br> 对于lfOutPrecision, lfClipPrecision, lfQuality一般应用于对屏幕之外<br> 的输出设备，通常采用默认值。采用lfPitchAndFamily来确定采用定宽或可<br> 变字体和字体的家族。以lfFaceName来通过名称选择采用的字体。<br> 另外应当注意在Windows环境下，每种字体具体输出为何种形式取决于很多<br> 因素，需要对以上这些参数进行有效的组合才能达到所要的效果。<br> </td> </tr></table><p align="center"> </p></body></html>⌨️ 快捷键说明
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