防止用户误输入是软件开发的一项必不可少的工作，除才之外，还要为用户的使用提供最大方便。当然，我们可以利用或开发新的组件，以完成这些功能。但是，在团队开发中，每个成员都用自己认为不错的组件开发自己所承担的模块，会给软件的后期维护带来麻烦。交工的时候，项目负责人可不买你的帐。如果你用函数调用来完成这些功能，老盖也管不着。下面就是针对常用delphi组件的限制用户输入函数，但愿网友们能用的上。（一）TEdit、TDBEdit、TComboBox、TDBComboBox的输入分三种类型限制：（1）任意输入（2）整数输入（3）浮点数输入限制的项目如下：（1）整数输入只能输入数字0-9、+、-（2）浮点输入只能输入数字0-9、+、-、.（3）+和-只能有其一，并且只能出现在最前面（4）.只能有一个（5）限制小数位数函数如下：procedure MxFormatKeyPress(Text:string;SelStart,SelLength:integer; var Key:Char;EditType:integer;Digits:integer);begin if (Key=#27) or (Key=#8) or (EditType=1) then exit; if EditType=2 then if not (Key in ['0'..'9','+','-'] ) then Key:=#0; if EditType=3 then if not (Key in ['0'..'9','+','-','.'] ) then Key:=#0; //控制+- if (Key ='-') or (Key='+' ) then begin if ((Pos('-',Text) > 0) or (Pos('+',Text) > 0 )) and (SelLength=0 ) then Key:=#0; if SelStart > 0 then Key:=#0; end; //控制. if (Key = '.') and (EditType=3 ) then begin if (Pos('.',Text) > 0) and (not((SelStart =Pos('.',Text) ))) then Key:=#0; if SelStart=0 then Key:=#0; if (Digits>0) and (SelStart+SelLength 0) and (EditType=3) then if (pos('.',Text )>0 ) and (SelStart>=pos('.',Text)) then if length(Text)-pos('.',Text )>=Digits then Key:=#0; end; 此函数在所限制组件的OnKeyPress事件中调用。Key即为OnKeyPress携带的 Key:Char参数；EditType为限制的类型：1-任意输入；2-整数输入；3-浮点输入； Digits为浮点数输入时小数的位数，如果是零，则可输入任意位数。另外，此 函数只适用于有Text、SelStart、SelLength等属性的TWinControl类的派生类。 具体限制各组件的二级函数如下： 限制TEdit、TDBEdit： procedure MxFormatEditKeyPress(Edit:TCustomEdit;var Key:Char;EditType:integer; Digits:integer); begin MxFormatKeyPress(Edit.Text,Edit.SelStart,Edit.SelLength,Key,EditType,Digits); end; 限制TComboBox： procedure MxFormatComboKeyPress(Combo:TComboBox;var Key:Char;EditType:integer; Digits:integer); begin MxFormatKeyPress(Combo.Text,Combo.SelStart,Combo.SelLength,Key,EditType,Digits); end; 限制TDBComboBox： procedure MxFormatDBComboKeyPress(Combo:TDBComboBox;var Key:Char; EditType:integer;Digits:integer); begin MxFormatKeyPress(Combo.Text,Combo.SelStart,Combo.SelLength,Key,EditType,Digits); end; 调用示例： 假如Form1上有一ComboBox1，让用户只输入浮点数，并且小数位数为两位。则 可以在ComboBox1的OnKeyPress事件中调用上面的函数，代码如下： procedure TForm1.ComboBox1KeyPress(Sender: TObject; var Key: Char); begin MxFormatComboKeyPress(Combobox1,Key,3,0); end; 如果你的窗体上有多各TComboBox，并且限制类型一致，则不必每个TComboBox都 书写代码，只需为其中一个编写事件处理代码，其它作连接即可。 procedure TForm1.ComboBox1KeyPress(Sender: TObject; var Key: Char); begin MxFormatComboKeyPress(Sender as TComboBox,Key,3,0); end; 其它组件调用方法同上。 （二）时间的输入 限制类型： （1）时分 （2）时分秒 组件采用TMaskEdit，数据敏感采用TDBEdit。 限制项目如下： （1）小时只能输入0-23 （2）分钟不超过59 （3）秒不超过59 （4）用户只能全删，而不能只删某一位数据 （5）箭头键可以更改时间 需要在组件的OnKeyPress和OnKeyDown事件中分别书写代码。 procedure MxFormatTimeKeyPress(ctl:TCustomMaskEdit;TimeFormat:integer; var Key:Char;dts:TDataSource); var TextSave:string; EditingPos:integer;//1-h 2-m 3-s i:integer; NumChars:set of Char; SelStartSave,SelLengthSave:integer; CharValid:boolean; begin NumChars:=['0'..'9']; if Key=^V then Key:=#0; if not (Key in NumChars ) then exit; TextSave:=ctl.Text; SelStartSave:=ctl.SelStart; SelLengthSave:=ctl.SelLength; case ctl.SelStart of 0,1: EditingPos:=1; 3,4: EditingPos:=2; 6,7: EditingPos:=3; else EditingPos:=0; end; /// CharValid:=true; case EditingPos of 1: begin if SelStartSave=0 then begin if not (Key in ['0'..'2']) then CharValid := False; if (Key ='2' ) and (TextSave[2] in ['4'..'9']) then CharValid:=false; end; if (SelStartSave = 1) and (TextSave[1] = '2') and (not (Key in ['0'..'3'])) then CharValid := False; end; 2: if (SelStartSave = 3) and not (Key in ['0'..'5']) then CharValid := False; 3: if (SelStartSave = 6) and not (Key in ['0'..'5']) then CharValid := False; end; if not CharValid then begin Key:=#0;exit; end; if dts<>nil then dts.DataSet.Edit; if not (SelStartSave in [2,5]) then TextSave[SelStartSave+1]:=Key; if SelLengthSave>1 then begin for i:=SelStartSave+2 to SelStartSave+SelLengthSave do if i in [1,2,4,5,7,8] then TextSave[i]:='0'; SelLengthSave:=1; end; for i:=1 to length(TextSave) do if (i in [1,2,4,5,7,8]) and (not (TextSave[i] in NumChars ) ) then TextSave[i]:='0'; if SelStartSave in [1,4] then SelStartSave :=SelStartSave+2 else if SelStartSave=length(TextSave)-1 then SelStartSave :=SelStartSave else SelStartSave :=SelStartSave+1; / ctl.Text :=TextSave; ctl.SelStart :=SelStartSave; ctl.SelLength :=SelLengthSave; Key:=#0; end; //此函数分割时间，因为有时候会遇到非法的时间字符串，所以不采用DecodeTime。 function MxSplitStr(SourceStr,SplitStr:string;var ResultArray:array of string):integer; var i:integer; strTmp:string; begin strTmp:=SourceStr; i:=0; while pos(SplitStr,strTmp)>0 do begin ResultArray[i]:=copy(strTmp,1,pos(SplitStr,strTmp)-1); strTmp:=copy(strTmp,pos(SplitStr,strTmp)+length(SplitStr),length(strTmp)- pos(SplitStr,strTmp)); i:=i+1; end; ResultArray[i]:=strTmp; result:=i+1; end; //此函数检查字符串是否为合法的时间 function TimeValid(TimeStr:string;TimeFormat:integer):boolean; var h,m,s:string; ary:array[0..2] of string; SplitRet:integer; i:integer; begin result:=true; SplitRet:=MxSplitStr(TimeStr,':',ary); if SplitRet<2 then begin result:=false; exit; end; for i:=0 to 2 do begin if length(ary[i])>2 then begin result:=false; exit; end; ary[i]:=trim(ary[i]); end; h:=ary[0];m:=ary[1]; if TimeFormat=3 then s:=ary[2]; /// if (h='') or (strtoint(h)>23 ) then begin result:=false; exit; end; if (m='' ) or (strtoint(m)>59) then begin result:=false; exit; end; if (TimeFormat=3) then if (s='') or (strtoint(s)>59) then begin result:=false; exit; end; end; //此函数对时分秒进行加减运算 function IncTime(ATime: TDateTime; Hours, Minutes, Seconds, MSecs: Integer): TDateTime; begin Result := ATime + (Hours div 24) + (((Hours mod 24) * 3600000 + Minutes * 60000 + Seconds * 1000 + MSecs) / MSecsPerDay); if Result < 0 then Result := Result + 1; end; //时分秒加减运算的二级函数 function TimeAdd(TimeStr:string;TimeFormat:integer; HStep,MStep,SStep:integer):string; var dt:Tdatetime; begin if not TimeValid(TimeStr,TimeFormat) then if TimeFormat=2 then begin result:='00:00'; exit; end else begin result:='00:00:00';exit; end; dt:=strtotime(TimeStr); if TimeFormat=2 then result:=FormatDateTime('hh:mm',IncTime(dt,HStep,MStep,SStep,0)) else result:=FormatDateTime('hh:mm:ss',IncTime(dt,HStep,MStep,SStep,0)) end; //限制组件的OnKeyDown procedure MxFormatTimeKeyDown(ctl:TCustomMaskEdit;TimeFormat:integer; var Key:word;Shift: TShiftState;dts:TDataSource); var TextSave:string; SelStartSave,SelLengthSave:integer; EditingPos:integer;//1-h 2-m 3-s i:integer; begin if (ssShift in Shift) and (Key<>vk_delete ) then exit; if not (Key in [vk_delete,vk_back,vk_up,vk_down] ) then exit; if (dts<>nil ) and (not dts.DataSet.Active ) then exit; if (dts<>nil) and (not dts.DataSet.Modified ) then dts.DataSet.Edit; // TextSave:=ctl.Text; SelStartSave:=ctl.SelStart; SelLengthSave:=ctl.SelLength; case SelStartSave of 0,1: EditingPos:=1; 3,4: EditingPos:=2; 6,7: EditingPos:=3; else EditingPos:=0; end; if SelStartSave=length(TextSave) then EditingPos:=TimeFormat; if Key=vk_delete then begin if SelLengthSave=length(TextSave) then TextSave:='' else begin if not (SelStartSave in [2,5]) then TextSave[SelStartSave+1]:='0'; if SelLengthSave>1 then begin for i:=SelStartSave+2 to SelStartSave+SelLengthSave do if i in [1,2,4,5,7,8] then TextSave[i]:='0'; SelLengthSave:=1; end; end; Key:=0; end; if Key=vk_back then begin if SelLengthSave=length(TextSave) then TextSave:='' else if SelLengthSave<=1 then begin if not (SelStartSave in [3,6]) then begin TextSave[SelStartSave]:='0'; SelStartSave:=SelStartSave-1; end else begin TextSave[SelStartSave-1]:='0'; SelStartSave:=SelStartSave-2; end; SelLengthSave:=1; end else begin for i:=SelStartSave+1 to SelStartSave+SelLengthSave do if i in [1,2,4,5,7,8] then TextSave[i]:='0'; SelLengthSave:=1; end; Key:=0; end; /// if (Key=vk_up) or (Key=vk_down ) then begin if trim(TextSave)=':' then begin if TimeFormat=2 then TextSave:='00:00' else TextSave:='00:00:00' end else begin if Key=vk_up then case EditingPos of 1: TextSave:=TimeAdd(TextSave,TimeFormat,1,0,0); 2: TextSave:=TimeAdd(TextSave,TimeFormat,0,1,0); 3: TextSave:=TimeAdd(TextSave,TimeFormat,0,0,1); end; if Key=vk_down then case EditingPos of 1: TextSave:=TimeAdd(TextSave,TimeFormat,-1,0,0); 2: TextSave:=TimeAdd(TextSave,TimeFormat,0,-1,0); 3: TextSave:=TimeAdd(TextSave,TimeFormat,0,0,-1); end; end; end; /// ctl.Text :=TextSave; ctl.SelStart :=SelStartSave; ctl.SelLength :=SelLengthSave; end; 以上函数的TimeFormat参数代表时间的类型：1-时:分；2-时:分:秒 要完成对时间的输入限制，只需调用上面的MxFormatTimeKeyPress， MxFormatTimeKeyDown两个函数。 调用示例： （1）TMaskEdit procedure TForm1.MaskEdit1KeyDown(Sender: TObject; var Key: Word; Shift: TShiftState); begin MxFormatTimeKeyDown(Sender as TCustomMaskEdit,2,Key,Shift,nil); end; procedure TForm1.MaskEdit1KeyPress(Sender: TObject; var Key: Char); begin MxFormatTimeKeyPress(Sender as TCustomMaskEdit,2,Key,nil); end; 并且，TMaskEdit的EditMask属性设为'99:99' （2）TDBEdit procedure TForm1.DBEdit1KeyPress(Sender: TObject; var Key: Char); begin MxFormatTimeKeyPress(Sender as TCustomMaskEdit,2,Key,(Sender as TDBEdit).DataSource); end; procedure TForm1.DBEdit1KeyDown(Sender: TObject; var Key: Word; Shift: TShiftState); begin MxFormatTimeKeyDown(Sender as TCustomMaskEdit,2,Key,Shift,(Sender as TDBEdit).DataSource); end; 在TDBEdit所连接的数据源打开后，设定所连字段的EditMask属性为99:99： DBEdit1.Field.EditMask :='99:99'; （三）日期的输入 采用Rx的日期组件TDateEdit、TDBDateEdit。如果你还没安装，请在本站下载。 无需对日期的输入作限制，只需方便用户的输入。即：箭头键可以改变相应的 日期元素，因为Rx五次功能。函数如下： procedure MxSpinRxDateEdit(Edit:TCustomDateEdit;Key:word;Shift:TShiftState; dts:TDataSource); var DateStr,Mark,str:string; MarkPos1,MarkPos2:integer; DateOrd:TDateOrder; DateFlag,step:integer; OldSelStart:integer; begin if Shift<>[] then exit; if not (Key in [vk_up,vk_down] ) then exit; if (dts<>nil ) and (not dts.DataSet.Active ) then exit; if (dts<>nil ) and (not dts.DataSet.Modified) then dts.DataSet.Edit; OldSelStart:=Edit.SelStart; DateStr:=Edit.EditText; Mark:=GetDateMark(DateStr); MarkPos1:=pos(Mark,DateStr); str:=copy(DateStr,MarkPos1+1,length(DateStr)-MarkPos1); MarkPos2:=MarkPos1+pos(Mark,str); DateOrd:=GetDateOrder(ShortDateFormat); DateFlag:=GetDateFlag(MarkPos1,MarkPos2,Edit.SelStart,DateOrd); if Key=vk_up then step:=1 else if Key=vk_down then step:=-1 else step:=0; case DateFlag of 1: Edit.Date := IncYear(Edit.Date ,step); 2: Edit.Date := IncMonth(Edit.Date ,step); 3: Edit.Date := IncDay(Edit.Date ,step); end; Edit.SelStart :=OldSelStart; end; 此函数在组件的OnKeyDown事件中调用，对于TDateEdit，DataSoure参数为nil。 记着引用Rx的单元ToolEdit和DateUtil。 调用示例： procedure TForm1.DateEdit1KeyDown(Sender: TObject; var Key: Word; Shift: TShiftState); begin MxSpinRxDateEdit(Sender as TCustomDateEdit,Key,Shift,nil); end; procedure TForm1.DBDateEdit1KeyDown(Sender: TObject; var Key: Word; Shift: TShiftState); begin MxSpinRxDateEdit(Sender as TCustomDateEdit,Key,Shift,(Sender as TDBDateEdit).DataSource); end;
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