Procedure runselect(P:pointer);stdcall; begin adoquery1.Close; adoquery1.SQL.Clear; adoquery1.SQL.Add('****'); Form2:=TForm2.Create(Application); try adoquery1.Open; except showmessage('异常处理'); end; end; procedure TForm1.SpeedButton1Click(Sender: TObject); var thid:dword; begin createthread(nil,0,@runselect,nil,0,thid); end; 能编译，但不能执行，帮我看看吧。

function runselect(P:pointer): dword; stdcall; Remember to initialize COM in your thread.... BTW, why use API in creating the thread? I think you should make use of the TThread class instead...

不好意思，我从没有写过多线程， 能给我改一改吗？ 不胜感激。

error message:'access villoation at 0x004c026e:read of address 0x0000000'

'access villoation' 是因為你用的Object不存在所造成的 在Thread 中使用 COM Object 要先 CoInitialize Procedure runselect; stdcall; var adoquery1: TADOQuery; begin CoInitialize(nil); adoquery1 := TADOQuery.Create(nil); try adoquery1.ConnectionString := 'Provider=....'; adoquery1.SQL.Text := 'select * from table'; adoquery1.Open; finally adoquery1.Free; CoUninitialize(); end; end; procedure TForm1.SpeedButton1Click(Sender: TObject); var thid: DWord; begin createthread(nil,0,@runselect,nil,0,thid); end;

uses activex 加入 CoInitialize(nil); CoUninitialize(); 错误依旧。

unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, DB, ADODB, StdCtrls; type ado_exec = class(TThread) private Procedure runselect; { Private declarations } protected procedure Execute; override; end; type TForm1 = class(TForm) Button1: TButton; ADOQuery1: TADOQuery; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation uses Unit2; {$R *.dfm} //##################### procedure ado_exec.Execute; begin Synchronize(runselect); end; Procedure ado_exec.runselect; var adoquery1: TADOQuery; begin adoquery1:=TADOQuery.Create(nil); try adoquery1.Close; adoquery1.SQL.Clear; adoquery1.SQL.Add('****'); Form2:=TForm2.Create(Application); try adoquery1.Open; except showmessage('异常处理'); end; finally adoquery1.Free; end; end; //##################### procedure TForm1.Button1Click(Sender: TObject); begin ado_exec.Create(false); end; end.

真是见鬼了，错误依旧。

引言: 真是见鬼了，错误依旧。

I have tested... both 1) & 2) works 1) 

function RunSelect: dword; stdcall;
begin
    Result := S_OK;
end;

2) procedure RunSelect(Param: integer); stdcall; However, you should be careful that VCL is not thread safe (and same to some Windows APIs), this is an example:

unit Unit1;    interface    uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;    const
    WM_TEST = WM_USER   1;    type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
    procedure WMText(var Msg: TMessage); message WM_TEST;
  public
    { Public declarations }
  end;    var
  Form1: TForm1;    implementation    {$R *.dfm}    function RunSelect: dword; stdcall;
begin
    Result := S_OK;
    SendMessage(Form1.Handle,WM_TEST,0,0);
end;    procedure TForm1.Button1Click(Sender: TObject);
var
    thid: dword;
begin
    CreateThread(nil,0,@RunSelect,nil,0,thid);
end;    procedure TForm1.WMText(var Msg: TMessage);
begin
    ShowMessage('Test');
end;    end.

你的錯誤有二個以上！ 第一： 你的錯誤訊息 'access villoation' 是因為你用的Object不存在所造成的 看起來是 adoquery1 不存在，也就是沒有 create 就用它 或是沒有指正確的物件… 第二： 在Thread 中使用 COM Object 要先 CoInitialize 請你先查第一個錯誤，是在用那一個物件方法出錯！…

unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, Grids, DBGrids, DB, ADODB, Activex; type TForm1 = class(TForm) ADOQuery1: TADOQuery; DataSource1: TDataSource; DBGrid1: TDBGrid; Button1: TButton; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.dfm} function RunSelect: dword; stdcall; var adoquery1:tadoquery; begin CoInitialize(nil); adoquery1.close; adoquery1.open; CoUninitialize(); end; procedure TForm1.Button1Click(Sender: TObject); var thid: dword; begin CreateThread(nil,0,@RunSelect,nil,0,thid); end; end. error message:error message:'access villoation at 0x00487c2a:read of address 0x0000000' 活见鬼。

Please refer to solnone's post.. You need to create ADOQuery first.

unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, Grids, DBGrids, DB, ADODB, Activex; type TForm1 = class(TForm) ADOQuery1: TADOQuery; DataSource1: TDataSource; DBGrid1: TDBGrid; Button1: TButton; Edit1: TEdit; procedure Button1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; var Form1: TForm1; implementation {$R *.dfm} function RunSelect: dword; stdcall; var adoquery1:tadoquery; begin CoInitialize(nil); adoquery1:=tadoquery.Create(nil); try adoquery1.close; adoquery1.ConnectionString:='Provider=***'; adoquery1.SQL.Clear; adoquery1.SQL.Add('select * from table'); adoquery1.open; finally adoquery1.free; CoUninitialize(); end; end; procedure TForm1.Button1Click(Sender: TObject); var thid: dword; begin CreateThread(nil,0,@RunSelect,nil,0,thid); end; end. 这个写table并没有open,为什么？

Proper settings of the ADOQuery (e.g. ConnectionString, SQL)?

ConnectionString和SQL肯定没错， 如果我直接将adoquery1.active:=true， 则可查询数据。 adoquery1.ConnectionString:='Provider=MSDAORA.1;Password=123;User ID=123;Data Source=ho;Persist Security Info=True'; adoquery1.SQL.Add('select * from table1);

第一種方法，直接使用 Form1.ADOQuery1 function RunSelect: dword; stdcall; begin CoInitialize(nil); Form1.ADOQuery1.close; Form1.ADOQuery1.open; CoUninitialize(); end; 第二種方法，參考到 Form1.ADOQuery1 function RunSelect: dword; stdcall; var adoquery1:tadoquery; begin adoquery1 := Form1.ADOQuery1; CoInitialize(nil); adoquery1.close; adoquery1.open; CoUninitialize(); end; 第三種方法，自已建 ADOQuery1 Procedure runselect; stdcall; var adoquery1: TADOQuery; begin CoInitialize(nil); adoquery1 := TADOQuery.Create(nil); try adoquery1.ConnectionString:='Provider=MSDAORA.1;Password=123;User ID=123;Data Source=ho;Persist Security Info=True'; adoquery1.SQL.Add('select * from table1'); adoquery1.Open; finally adoquery1.Free; CoUninitialize(); end; end;