Delphi复习代码

原作者: [db:作者] 来自: [db:来源] 收藏邀请

1、取得可文件路径

Path := ExtractFilePath(Application.ExeName); //取得可执行文件路径 TXMLDocument.Create(ExtractFilePath(Application.ExeName)+ '001.xml'）

2、DisableControls EnableControls

ClientDataSet.DisableControls;

...

for I := 0 to 10000 do

begin

ClientDataSet.Append;

...

ClientDataSet.Post;

end;...

ClientDataSet.EnableControls

3、XML的解析

<?xml version="1.0" encoding="utf-8"?>
<root>
  <info  />
  <info  />
</root> 

var
  XMLDoc: TXMLDocument;
  iNode, tmpNode: IXMLNode;
begin
  with ClientDataSet1 do
  begin
    FieldDefs.Add('id',ftString,250);
    FieldDefs.Add('name',ftString,100);
    CreateDataSet;
  end;

  XMLDoc:= TXMLDocument.Create(Owner);
  XMLDoc.FileName:='E:\1.xml';
  XMLDoc.Active:=True;
  iNode := XMLDoc.DocumentElement.ChildNodes.First;
  while iNode<> nil do
  begin
    ClientDataSet1.AppendRecord([iNode.Attributes['id'],iNode.Attributes['name']]);
    iNode:= iNode.NextSibling;
  end;
  XMLDoc.Free;
end;

3、DelPhi 动态给ComBoBox赋值，从ComBoBox中取值

1、把数据库中的项目信息（项目名称、项目编号）动态赋给ComBoBox

 cbProjectName.Items.Clear;
   with adoQryProject do
   begin
     First;
     while not Eof do
     begin
       ProjectNameStr := fieldByName('ProjectName').AsString;
       if Trim(ProjectNameStr) <> '' then
         cbProjectName.Items.AddObject(ProjectNameStr, TObject(fieldByName('ProjectID').AsInteger));
       Next;
     end;
   end; 

2、读取ComBoBox中的值

ProjectID:= IInteger(cbProjectName.Items.Objects[cbProjectName.ItemIndex]);
ProjectName:= cbProjectName.Text; 

3、快速定位到某个字段或数据:

1>、设置Combobox控件的AutoComplete属性为true即可; 

2>、combobox1.ItemIndex := Combobox1.Items.IndexOf(trim(edit1.text));

4、图片的存取

1、存图片到数据库 
var
   PicStream: TMemoryStream;

 if imgBugPic.Picture.Graphic <> nil then
  begin
    PicStream := TMemoryStream.Create; //  创建内存流
    imgBugPic.Picture.Graphic.SaveToStream(PicStream);
    TBlobField(FieldByName('BUGPic')).LoadFromStream(PicStream);
    PicStream.Free;
  end; 

2、从数据库中读取图片并显示
var
  PicStream: TMemoryStream; 
 if not FieldByName('BUGPic').IsNull then
      begin
        try
          PicStream := TMemoryStream.Create;
          TBlobField(FieldByName('BUGPic')).SaveToStream(PicStream);
          PicStream.Position := 0;
          imgBugPic.Picture.Bitmap.LoadFromStream(PicStream);
          PicStream.Free;
        except
          ShowMessage('对不起，图片有问题.');
        end;
      end;

5、动态创建窗体

//第一种方式
procedure TForm1.btn1Click(Sender: TObject);
begin
With TForm2.Create(Application) do
Try
   ShowModal;
finally
   free;
end;
end;
 
//第二种方式
procedure TForm1.btn2Click(Sender: TObject);
begin
  if not assigned(Form2) then
  begin
    Form2:=TForm2.Create(nil);
    Form2.Show;
  end
end;
 
//第二种方式创建的的窗体需要在FORM2里释放资源
procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);
begin
   Form2:=nil;           //Form对象指向空地址
  Action := cafree;     //Form关闭后释放占用的内存
end;

6、错误抛出异常

try
     ....(需要执行的代码)
except
  on e:exception do
     application.MessageBox(pchar(e.Message), '错误提示', 0);
end;

7、本月的第一和最后一天

USER ：DateUtils
procedure TForm1.btn1Click(Sender: TObject);
begin
     mmo1.Lines.Add(FormatDateTime('yyyy-mm-dd',StartOfTheMonth(Now)));
     mmo1.Lines.Add(FormatDateTime('yyyy-mm-dd',EndOfTheMonth(Now)));
   //mmo1.Lines.Add(DateTimeToStr(StartOfTheMonth(Now)));
   //mmo1.Lines.Add(DateTimeToStr(EndOfTheMonth(Now)));
end;

8、判断文件夹，没有创建

procedure TForm1.Button1Click(Sender: TObject);
var
Pach:string;
begin
Pach:='E:\123\223';                //定义目录地址
if not DirectoryExists(pach) then  //查找文件夹是否存在
  begin
  //建立文件夹(ForceDirectories可建立多级目录，创建单级目录用：CreateDirectory)
  ForceDirectories(Pach);
  end
else
  begin
  showmessage('目录已经存在');
  end;
end;

9、对Edit 循环赋值

var
  i:Integer;
  control:TComponent;
begin
  for i := 0 to 99 do
  begin
    control := FindComponent('Edit'+IntToStr(i));
    if control <> nil then
    begin
      TEdit(control).Text := IntToStr(i);
    end;
  end;
end;

10、画曲线

TeeChart 动态建曲线

var
  i:Integer;
  Series:array of TFastLineSeries;    //这里最好写在全局变量中
begin
  SetLength(Series,MyTHead.Count);
  Chart1.SeriesList.Clear;
  for i:= 0 to MyTHead.Count-1 do  //MyTHead是一个Tstringlist，根据MyTHead来动态创建曲线的数量
  begin
    Series[i]:=TFastLineSeries.Create(nil);
    Series[i].ParentChart:= Chart1; //在名为CHART1的组件上建曲线
    Series[i].Title:= MyTHead[i];
  end;
end;

11、释放判断

XML := TNativeXml.Create(nil);

if assigned(XML)then
begin
  FreeAndNil(XML);
end;

12、锁定控件 CDS内存表 XML赋值

 with ClientDataSet1 do
    begin
      //EmptyDataSet;
      //Close;
      if FieldDefs.Count<=0 then
      begin
        FieldDefs.Clear;
        FieldDefs.Add('id',ftInteger,0);
        FieldDefs.Add('cname',ftString,100);
        FieldDefs.Add('contact',ftString,100);
        FieldDefs.Add('phone',ftString,100);
        FieldDefs.Add('addr',ftString,100);
        FieldDefs.Add('remark',ftString,100);
        //IndexDefs.Add('PK', 'id', [ixPrimary, ixUnique]);
        CreateDataSet;
      end;
      DisableControls;

     // XML.Clear;
      if not assigned(XML) then
      XML := TNativeXml.CreateName('companies');

      H := TAuthHeader.Create;
      H.UserName := '555' ; //这里只是举个例子
      H.PassWord := '555';
      Headers := WebServer as ISOAPHeaders;
      Headers.Send(H);

      retStr :=WebServer.findCompany ;
      XML.ReadFromString(retStr);
      XML.XmlFormat := xfReadable;
      //XML.SaveToFile('D:\com');

     // showmessage(IntToStr(list.Count));
      if not assigned(list) then list:=TList.Create
      else list.Clear;


      XML.Root.NodesByName('company', list);
      //showmessage('2');
      // ClientDataSet1.r
      MergeChangeLog;
      EmptyDataSet;
      listcount := list.Count;
      for i := 0 to listcount - 1 do
      begin
         node := list[i];
         if  node.ReadInteger('id')>0 then
         begin
            Append;
            FieldByName('id').AsInteger := node.ReadInteger('id');
            FieldByName('cname').AsString := node.ReadString('cname');
            FieldByName('addr').AsString := node.ReadString('addr');
            FieldByName('contact').AsString := node.ReadString('contact');
            FieldByName('phone').AsString := node.ReadString('phone');
            FieldByName('remark').AsString := node.ReadString('remark');
            Post;
         end;
         //DisPose(list[i]);
      end;
       EnableControls;
       Open;

    end;

13、窗体拖动

procedure TMain_Frm.imgbdMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
begin
    if (ssleft in shift) then
  begin
    releasecapture;
    perform(wm_syscommand, $f012, 0);
  end;
end;

14、删除提示

if Application.MessageBox('删除不能恢复，确认删除吗？', '删除提示', MB_OKCANCEL + MB_ICONQUESTION)=mrOk then
begin
　　ShowMessage('你选择的OK！');
end;

15、生成GUID guid

function GetGUID: string;
var
  Guid: TGUID;
begin
  CreateGUID(Guid);
  Result := GUIDToString(Guid);
end;

16、检测电话号码

function TMain_frm.IsMobileNumber(num: string): boolean;
begin
  Result := False;
  if length(trim(Num)) <> 11 then
    Exit;
  if ((copy(num, 1, 2) <> '13') and (copy(num, 1, 2) <> '15')) and (copy(num, 1, 2) <> '18') and (copy(num, 1, 2) <> '14') and (copy(num, 1, 2) <> '17'))

then Exit; try StrToInt(copy(num, 3, 9)); Result := True; except end; end;

17、改变DBGrid显示的内容

procedure TAppInterface_frm.dbgrd1DrawColumnCell(Sender: TObject;   const Rect: TRect; DataCol: Integer; Column: TColumn; State: TGridDrawState);
var
  str:string;
begin
  if (Column.Field <>nil) and (Column.FieldName = 'isencrypt') then
  begin
    if Column.Field.IsNull then exit;
    case integer(Column.Field.value)  of
       0:str:='公开';
       1:str:='传值';
       2:str:='Header';
    end;
    (Sender as TDBGrid).Canvas.TextRect(Rect,Rect.Left,Rect.Top,str);
  end;

end;

procedure TMaindlg.ADOQueryDisplayIsUsedGetText(Sender: TField; var Text: String; DisplayText: Boolean);
beginif  ADOQueryDisplay.FieldByName('Sex').AsString='0' then
          text:='女'
      else
          text:='男';
end;

DrawDataCell(ARect, DrawColumn.Field, AState);//是单元格 Dbgrid中填充数据时触发该事件
DrawColumnCell(ARect, ACol, DrawColumn, AState);//是列 Dbgrid生成每一列的时候触发该事件

18、Label自动换行先将Autosize=false; 再设WordWrap=true;

19、ListBox基本使用方法：

一）添加
ListBox1.Add(EditBox1.Text);//添加到末尾

Items.Append('Append');//同Add

ListBox1.insert(0，EditBox1.Text);//添加到开头


//TcxImageList 参数 序号 内容 图标序号
lbxAppSupply.InsertItem(i,node.ReadString('mname')+' '+node.ReadString('name'),Random(2));
//对应的values值
lbxAppSupply.Values[i] := node.ReadString('id');

imglist1.Items[imglist1.ItemIndex];//内容
imglist1.Values[imglist1.ItemIndex];//值

//支持多选
for I := 0 to imglist1.Count - 1 do
  begin
    if imglist1.Selected[I] then
    begin
      mmo1.Text := mmo1.Text+'Selected[i]:'+imglist1.Items[i]+#13#10;
      mmo1.Text := mmo1.Text+'Values[i]:'+imglist1.Values[i]+#13#10;
    end;   
  end;  


二）删除

ListBox1.DeleteSelected;//删除选择项 包括多选

imglist1.Items.Delete(imglist1.ItemIndex);//删除选择项

三）选定

//TcxImageList 
imglist1.Selected[imglist1.Items.IndexOf('学生管理系统')]:= True;

ShowMessage(imglist1.Items[imglist1.ItemIndex]);



List为单选的取值

1）ItemIndex：为选中的list序列号从0开始，没有选时为-1

2）imglist1.Items[imglist1.ItemIndex]：为当前选中的内容

3）Items.Strings[imglist1.ItemIndex]=Items[imglist1.ItemIndex]

4）GetCount为当前记录 因为从0开始，所以可以作为插入序号

20、Query字段属性显示添加

procedure TfrmYiSheng.qry1isUploadGetText(Sender: TField; var Text: string;
  DisplayText: Boolean);
begin
  inherited;
  if Sender.AsInteger = 1 then
    Text := '是 '
  else
    Text := '否 ';
end;

procedure TfrmYiSheng.qry1isUploadSetText(Sender: TField; const Text: string);
begin
  inherited;
  if Text = '是 ' then
    Sender.AsInteger := 1
  else
    Sender.AsInteger := 0;
end;

21、inc() dec()

inc有两种用法:
一个是inc(integer)，就是加1
比如
i := 100;
inc(i);
就是i变为101

另一个是inc(integer,integer)就是加n
比如
i:=100;
inc(i,50);
就是i变成150
---------------------------------
Dec是递减函数
i:=100;
dec(i);
i就变成99了,如果是dec(i,30)的话,那么i=100-30=70

22、 ChangeFileExt

function ChangeFileExt(const FileName, Extension: string): string;
var
  I: Integer;
begin
  I := LastDelimiter('.' + PathDelim + DriveDelim,Filename);
  if (I = 0) or (FileName[I] <> '.') then I := MaxInt;
  Result := Copy(FileName, 1, I - 1) + Extension;
end; 

比如:
s:=changefileext('f:\123.txt','.ini');
showmessage(s);//f:\123.ini

23、Ini 文件读写

procedure TfrmMain.FormCreate(Sender: TObject);
var
  S: string;
  Ini: TIniFile;
begin
  S := ChangeFileExt(Application.ExeName,'.ini');
  Ini := TIniFile.Create(S);
  try
    edReadFilename.Text := Ini.ReadString('Files','Read','');
    edWriteFilename.Text := Ini.ReadString('Files','Write','');
  finally
    Ini.Free;
  end;
end;

procedure TfrmMain.FormDestroy(Sender: TObject);
var
  S: string;
  Ini: TIniFile;
begin
  S := ChangeFileExt(Application.ExeName,'.ini');
  Ini := TIniFile.Create(S);
  try
    Ini.WriteString('Files','Read',edReadFilename.Text);
    Ini.WriteString('Files','Write',edWriteFilename.Text);
  finally
    Ini.Free;
  end;
end;

24、有序类型

Dec 将例程中的参数值递减1或一个特定的值，其中特定值可在
第二个可选参数中定义 
Inc 将例程中的参数值增加1或一个特定的值 
Odd 如果参数为奇数返回真 
Pred 根据参数在其数据类型定义中的序列，返回参数值的前驱值
Succ 返回参数值的后继值 
Ord 返回参数值在其数据类型值集合中的序号 
Low 返回参数对应的有序数据类型的最小取值 
High 返回参数对应的有序数据类型的最大取值