TREEVIEW控件怎么与数据库结合起来?!

Question

数据库怎么建,代码怎么写才能写出来树型目录来啊.!(主要是想能让TREEVIEW与数据 库结合)!另求代码!

Answer 1

//本单元实现：
//       1、建立ErrorTreeView与DataBase之间的关联关系；
//       2、ErrorTreeView的Editor方式的操作；unit ErrorTree;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls, Buttons, ComCtrls,Menus;type
  TErrorTreeForm = class(TForm)
    ErrorTreeView: TTreeView;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    BitBtn4: TBitBtn;
    BitBtn6: TBitBtn;
    Image1: TImage;
    Label1: TLabel;
    LabeledEditName: TEdit;
    Label2: TLabel;
    EditCode: TEdit;
    Label3: TLabel;
    BitBtn7: TBitBtn;
    BitBtn5: TBitBtn;
    BitBtn3: TBitBtn;
    Bevel1: TBevel;
    OpenDialog1: TOpenDialog;
    SaveDialog1: TSaveDialog;
    procedure FormShow(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn2Click(Sender: TObject);
    procedure BitBtn3Click(Sender: TObject);
    procedure BitBtn4Click(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure BitBtn5Click(Sender: TObject);
    procedure LabeledEditNameKeyUp(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure ErrorTreeViewChange(Sender: TObject; Node: TTreeNode);
    procedure BitBtn7Click(Sender: TObject);
    procedure BitBtn6Click(Sender: TObject);
    procedure ErrorTreeViewExpanding(Sender: TObject; Node: TTreeNode;
      var AllowExpansion: Boolean);
  private
    { Private declarations }
  public
    NewNode: TTreeNode;
      //新加Node
    function SaveTreeViewListToDatabase: Integer;
      //将树结构保存至数据库
    function GetMaxCode(SendNode: TTreeNode): Integer;
      //获得TreeView中当前同层的编号最大值
    function GetMaxCodeStr(SendNode: TTreeNode): String;
      //获得TreeView中当前同层的编号最新的字符型编号
    function GetCodeStrList(var CodeStrList: TStringList): Boolean;
      //获得索引编码列表
    function CheckExistsBool(CodeStr: String; CodeStrList: TStringList): Boolean;
      //检查数据库中是否已经存在该项
    function DataBaseClear: Boolean;
      //删除表中全部数据
    function DrawErrorTreeView: Integer;
      //从数据库中导入全部数据到TreeView
    function GetParentNodeForWrite(TierLen: Integer;
      ParentCodeStr: String; var ParentNode: TTreeNode): Integer;
      //为数据的写入从TreeView中找出父层节点
    { Public declarations }
  end;var
  ErrorTreeForm: TErrorTreeForm;
  function GetTreeViewMaxTierFromDatabase: Integer;
      //从数据表中获得TreeView的最大层数
  function GetParentCodeStr(CodeStr: String): string;
      //获得父节点的编号implementationuses DataModF;
{$R *.dfm}procedure TErrorTreeForm.FormShow(Sender: TObject);
begin
  NewNode:= TTreeNode.Create(Nil);
  DrawErrorTreeView;
  NewNode:= Nil;                         // 初始化NewNode
end;procedure TErrorTreeForm.BitBtn1Click(Sender: TObject);  //建同级目录
var
  CurNode: TTreeNode;
  MaxCodeStr: String;
begin
  LabeledEditName.Text:= '';
  EditCode.Text:= '';
  MaxCodeStr:= GetMaxCodeStr(NewNode);
  if ErrorTreeView.Selected<> nil then
  begin
    CurNode:= ErrorTreeView.Selected;
    NewNode:= ErrorTreeView.Items.AddChild(CurNode.Parent,MaxCodeStr);
  end
  else
    NewNode:= ErrorTreeView.Items.AddChild(nil,MaxCodeStr);
  NewNode.Selected:= True;
  EditCode.Text:= MaxCodeStr;
  LabeledEditName.SetFocus;
end;procedure TErrorTreeForm.BitBtn2Click(Sender: TObject);  //建下级目录
var
  CurNode: TTreeNode;
  MaxCodeStr: String;
begin
  LabeledEditName.Text:= '';
  EditCode.Text:= '';
  if ErrorTreeView.Selected= nil then Exit;
  CurNode:= ErrorTreeView.Selected;
  NewNode:= ErrorTreeView.Items.AddChild(CurNode,'');
  CurNode.Expand(True);
  NewNode.Selected:= True;
  MaxCodeStr:= GetMaxCodeStr(NewNode);
  MaxCodeStr:= Copy(MaxCodeStr,1,Length(MaxCodeStr)-1)+IntToStr(StrToInt(Copy(MaxCodeStr,Length(MaxCodeStr),1))-1);
    //最后一位减一
  NewNode.Text:= MaxCodeStr;
  EditCode.Text:= MaxCodeStr;
  LabeledEditName.SetFocus;
end;procedure TErrorTreeForm.BitBtn3Click(Sender: TObject);
begin
  Close;
end;procedure TErrorTreeForm.BitBtn4Click(Sender: TObject);
var
  CurNode,TempNode: TTreeNode;
begin
  if Application.MessageBox('确认删除吗？','警告',MB_ICONWARNING+MB_YESNO)<>mrYES then Exit;
  LabeledEditName.Text:= '';
  if ErrorTreeView.Selected= nil then Exit;
  CurNode:= ErrorTreeView.Selected;
  if not CurNode.IsFirstNode then           //删除前移动焦点，默认前移
    TempNode:= CurNode.GetPrev
  else
    TempNode:= CurNode.GetNext;
  CurNode.Delete;
  NewNode:= TempNode;
end;procedure TErrorTreeForm.FormCloseQuery(Sender: TObject;
  var CanClose: Boolean);
begin
  NewNode.Free;         //关闭时释放资源
end;procedure TErrorTreeForm.BitBtn5Click(Sender: TObject);
begin
  if SaveTreeViewListToDatabase = 0 then
    Close
  else
    Application.MessageBox('数据保存时出错！','错误',MB_ICONWARNING+MB_OK);
end;procedure TErrorTreeForm.LabeledEditNameKeyUp(Sender: TObject;
  var Key: Word; Shift: TShiftState);
begin
  if NewNode = nil then Exit;
  NewNode.Text:= EditCode.Text + '_' + LabeledEditName.Text;     //输入时TreeView同时更新
  if key = 13 then                         //回车时TreeView设置焦点
  begin
    NewNode.Selected:= True;
    ErrorTreeView.SetFocus;
  end;
end;procedure TErrorTreeForm.ErrorTreeViewChange(Sender: TObject;
  Node: TTreeNode);
begin
  if ErrorTreeView.Selected= nil then Exit;
  NewNode:= ErrorTreeView.Selected;
  LabeledEditName.Text:= Copy(NewNode.Text,(NewNode.Level+1)*2+2,Length(NewNode.Text)-(NewNode.Level+1)*2+1);
  EditCode.Text:= Copy(NewNode.Text,1,(NewNode.Level+1)*2);
  LabeledEditName.SetFocus;
end;function TErrorTreeForm.SaveTreeViewListToDatabase: Integer;
var
  CurNode: TTreeNode;
  i,j: Integer;
  NodeLevel: Integer;
  CodeStr, ErrorName, NodeTxt,S: String;
  CodeStrList: TStringList;
begin
  Result:= 0;
  CodeStrList:= TStringList.Create;
  try
   try
    GetCodeStrList(CodeStrList);
    with ErrorTreeView do
    begin
      CurNode:= Items.GetFirstNode;
      DataBaseClear;
      for i:= 0 to items.Count-1 do
      begin
        NodeLevel:= CurNode.Level;
        NodeTxt:= CurNode.Text;
        CodeStr:= Copy(NodeTxt,1,(NodeLevel+1)*2);
        ErrorName:= Copy(NodeTxt,(NodeLevel+1)*2+2,Length(NodeTxt));
        S:= 'insert ErrorName (故障名称id,故障名称) values('''+CodeStr+''','''+ErrorName+''')';
        with  DataMod.QryErrorName do
        begin
          Close;
          SQL.Clear;
          SQL.Add(s);
          Prepare;
          ExecSQL;
        end;
        CurNode:= CurNode.GetNext;
      end;
    end;
   finally
    CodeStrList.Free;
   end;
  except
   Result:= 1;
  end;
end;function TErrorTreeForm.GetMaxCode(SendNode: TTreeNode): Integer;
var
  TempNode: TTreeNode;
  i: integer;
begin
  if SendNode = Nil then
  begin
    Result:= 0;
    Exit;
  end;
  i:=0;
  if SendNode.Parent<>nil then
    TempNode:= SendNode.Parent.getFirstChild
  else
    TempNode:= ErrorTreeView.Items.GetFirstNode;  
  Repeat
    TempNode:= TempNode.getNextSibling;
    i:= i+1;
  until
    TempNode = nil;
  Result:= i;
end;function TErrorTreeForm.GetMaxCodeStr(SendNode: TTreeNode): String;
var
  MaxCode: Integer;
  ParentCodeStr: String;
begin
  MaxCode:= GetMaxCode(SendNode) + 1;
  if (SendNode <> nil) and (SendNode.Parent <> Nil) then
    ParentCodeStr:= Copy(SendNode.Parent.Text,1,(SendNode.Parent.Level+1)*2)
  else
    ParentCodeStr:='';
  if MaxCode < 10 then
    Result:= ParentCodeStr + '0'+IntToStr(MaxCode)
  else
    Result:= ParentCodeStr + IntToStr(MaxCode);
end;

Answer 2

function TErrorTreeForm.GetCodeStrList(
  var CodeStrList: TStringList): Boolean;
begin
  Result:= True;
 try
  CodeStrList.Clear;
  with DataMod.QryErrorName do
  begin
    Close;
    SQL.Clear;
    SQL.Add('select 故障名称id from errorname');
    Prepare;
    Open;
    while not eof do
    begin
      CodeStrList.Add(FieldByName('故障名称id').AsString);
      Next;
    end;
  end;
 except
  Result:= False;
 end;
end;function TErrorTreeForm.CheckExistsBool(CodeStr: String;
  CodeStrList: TStringList): Boolean;
var
  i: Integer;
begin
  Result:= False;
  for i:= 0 to CodeStrList.Count-1 do
    if CodeStrList[i]=CodeStr then
    begin
      Result:= True;
      Break;
    end;
end;procedure TErrorTreeForm.BitBtn7Click(Sender: TObject);
var
  txtFileName: TFileName;
begin
  SaveDialog1.Filter:= '文本文件(*.txt)|*.txt';
  if SaveDialog1.Execute then
  begin
    txtFileName:= SaveDialog1.FileName;
    try
      if not FileExists(txtFileName) then
        FileClose(FileCreate(txtFileName));
      ErrorTreeView.SaveToFile(txtFileName);
    except
      Application.MessageBox(Pchar('保存失败，请确认路径是否正确？'+#13#10+txtFileName),'错误',MB_ICONWARNING+MB_OK);
      Exit;
    end;
      Application.MessageBox(Pchar('文件保存成功！'+#13#10+txtFileName),'提示',MB_ICONWARNING+MB_OK);
  end;
end;procedure TErrorTreeForm.BitBtn6Click(Sender: TObject);
var
  txtFileName: TFileName;
begin
  OpenDialog1.Filter:= '文本文件(*.txt)|*.txt';
  if OpenDialog1.Execute then
  begin
    txtFileName:= OpenDialog1.FileName;
    try
      ErrorTreeView.Items.Clear;
      ErrorTreeView.LoadFromFile(txtFileName);
    except
      Application.MessageBox(Pchar('导入错误，请确认该文件是否有效？'+#13#10+txtFileName),'错误',MB_ICONWARNING+MB_OK);
      Exit;
    end;
      Application.MessageBox(Pchar('导入成功！'+#13#10+txtFileName),'提示',MB_ICONWARNING+MB_OK);
  end;
end;function TErrorTreeForm.DataBaseClear: Boolean;
begin
 try
  with DataMod.QryErrorName do
  begin
    Close;
    SQL.Clear;
    SQL.Add('delete from errorname');
    Prepare;
    ExecSQL;
  end;
 except
  Result:= False;
  Exit;
 end;
  Result:= True;
end;function TErrorTreeForm.DrawErrorTreeView: Integer;
var
  MaxCodeLen,TierLen: Integer;
  CodeStr,ParentCodeStr: String;
  ParentNode: TTreeNode;
begin
  Result:= 0;
  try
    MaxCodeLen:= GetTreeViewMaxTierFromDatabase;
    for TierLen:=1 to MaxCodeLen do
    begin
      with DataMod.QryErrorName do
      begin
      Close;
      SQL.Clear;
      SQL.Add('select 故障名称id,故障名称 from ErrorName ');
      SQL.Add('where len(故障名称id)='+IntToStr(TierLen*2));
      Prepare;
      Open;
//      showmessage(inttostr(recordcount));
      while Not Eof do
      begin
        CodeStr:= FieldByName('故障名称id').AsString;
        ParentCodeStr:= GetParentCodeStr(CodeStr);
        GetParentNodeForWrite(TierLen,ParentCodeStr,ParentNode);
        ErrorTreeView.Items.AddChild(ParentNode,CodeStr+'_'+FieldByName('故障名称').AsString);
        Next;
      end;
      end;
    end;
  except
    Result:= 1;
  end;
end;procedure TErrorTreeForm.ErrorTreeViewExpanding(Sender: TObject;
  Node: TTreeNode; var AllowExpansion: Boolean);
begin
//  if Node=nil then Exit;
//  TreeViewExpend(Node);
end;function TErrorTreeForm.GetParentNodeForWrite(TierLen: Integer;
  ParentCodeStr: String; var ParentNode: TTreeNode): Integer;
var
  TempNode: TTreeNode;
  i: Integer;
begin
  Result:= 0;
  with ErrorTreeView do
  begin
    TempNode:= Items.GetFirstNode;
    for i:= 0 to Items.Count-1 do
    begin
      if TempNode = nil then Break;
      if Copy(TempNode.Text,1,(TierLen-1)*2)='' then Break;  //检测是否为第一层
      if Copy(TempNode.Text,1,(TierLen-1)*2)=ParentCodeStr then
      begin
        ParentNode:= TempNode;
        Exit;
      end;
      TempNode:= TempNode.GetNext;
    end; 
    ParentNode:= Nil;
  end;
end;function GetTreeViewMaxTierFromDatabase: Integer;
begin
  with DataMod.QryErrorName do
  begin
    Close;
    SQL.Clear;
    SQL.Add('select maxlen=max(len(故障名称id)) from errorname');
    Prepare;
    Open;
    Result:= FieldByName('maxlen').AsInteger div 2;
  end;
end;function GetParentCodeStr(CodeStr: String): string;
begin
  Result:= Copy(CodeStr,1,Length(CodeStr)-2);
end;end.