c++builder 運行出錯

void __fastcall TForm1::FormCreate(TObject *Sender)
{
    ADOQuery1->Connection=ADOConnection1;
    ADOQuery1->Close();
    ADOQuery1->SQL->Clear();
    ADOQuery1->SQL->Add("select distinct state from authors");
    ADOQuery1->Open();

    while(!ADOQuery1->Eof){
        TreeView1->Items->Add(NULL,ADOQuery1->FieldByName("state")->AsString);
        ADOQuery1->MoveBy(1);
        }

    int n=TreeView1->Items->Count;
    TTreeNode* node[50];
    for(int i=0;i<n;i++){
        node[i]=TreeView1->Items->Item[i];
        }
    for(int i=0;i<n;i++){
        ADOQuery1->Close();
        ADOQuery1->SQL->Add("select distinct city from authors where state='"+node[i]->Text+"'");
        ADOQuery1->Open();
        while(!ADOQuery1->Eof){
        TreeView1->Items->AddChild(node[i],ADOQuery1->FieldByName("city")->AsString);
        ADOQuery1->MoveBy(1);
        }
    }

    //初始化串列列名
    StringGrid1->Cells[0][1]="au_id";
    StringGrid1->Cells[0][2]="au_fname";
    StringGrid1->Cells[0][3]="au_lname";
    StringGrid1->Cells[0][4]="phone";

    StringGrid2->Cells[0][1]="au_id";
    StringGrid2->Cells[0][2]="au_fname";
    StringGrid2->Cells[0][3]="au_lname";
    StringGrid2->Cells[0][4]="phone";
     int Rows1=1;
        while(!ADOQuery1->Eof){
                StringGrid1->Cells[1][Rows1]=ADOQuery1->FieldByName("au_id")->AsString;
                StringGrid1->Cells[2][Rows1]=ADOQuery1->FieldByName("au_lName")->AsString;
                StringGrid1->Cells[3][Rows1]=ADOQuery1->FieldByName("au_fName")->AsString;
                StringGrid1->Cells[4][Rows1]=ADOQuery1->FieldByName("phone")->AsString;
                ADOQuery1->MoveBy(1);
                Rows1++ ;
        }

        AnsiString ssql4 = "select * from authors where state='"+node[0]->Text+"' order by au_lname";
        ADOQuery1->Close();
        ADOQuery1->SQL->Clear();
        ADOQuery1->SQL->Add(ssql4);
        ADOQuery1->Open();

        int Rows2=1;
        while(!ADOQuery1->Eof){
                StringGrid2->Cells[1][Rows2]=ADOQuery1->FieldByName("au_lName")->AsString;
                StringGrid2->Cells[2][Rows2]=ADOQuery1->FieldByName("au_fName")->AsString;
                StringGrid2->Cells[3][Rows2]=ADOQuery1->FieldByName("au_id")->AsString;
                StringGrid2->Cells[4][Rows2]=ADOQuery1->FieldByName("phone")->AsString;
                ADOQuery1->MoveBy(1);
                Rows2++ ;
        }





}
//---------------------------------------------------------------------------

void __fastcall TForm1::TreeView1Click(TObject *Sender)
{
    TTreeNode * aNode=TreeView1->Selected;
    int r1=1;
    for(int i=1;i<StringGrid1->RowCount;i++){
    StringGrid1->Rows[i]->Clear();
    StringGrid2->Rows[i]->Clear();
    }

    AnsiString ssql1;
    ssql1="select * from authors where city='"+aNode->Text+"' order by au_id";  //運行之后，指到這行
    ADOQuery1->Close();
    ADOQuery1->SQL->Clear();
    ADOQuery1->SQL->Add(ssql1);
    ADOQuery1->Open();

    while(!ADOQuery1->Eof){
        TreeView1->Items->AddChild(aNode,ADOQuery1->FieldByName("city")->AsString);
        ADOQuery1->MoveBy(1);
        }

    while(!ADOQuery1->Eof){
    StringGrid1->Cells[r1][1]=ADOQuery1->FieldByName("au_id")->AsString;
    StringGrid1->Cells[r1][2]=ADOQuery1->FieldByName("au_lname")->AsString;
    StringGrid1->Cells[r1][3]=ADOQuery1->FieldByName("au_fname")->AsString;
    StringGrid1->Cells[r1][4]=ADOQuery1->FieldByName("phone")->AsString;
    ADOQuery1->MoveBy(1);
    r1++;
    }
    int r2=1;
    AnsiString ssql2="select * from authors where state='"+aNode->Text+"' order by au_fname";
    ADOQuery1->Close();
    ADOQuery1->SQL->Clear();
    ADOQuery1->SQL->Add(ssql2);
    ADOQuery1->Open();

    while(!ADOQuery1->Eof){
    StringGrid2->Cells[r2][1]=ADOQuery1->FieldByName("au_id")->AsString;
    StringGrid2->Cells[r2][2]=ADOQuery1->FieldByName("au_lname")->AsString;
    StringGrid2->Cells[r2][3]=ADOQuery1->FieldByName("au_fname")->AsString;
    StringGrid2->Cells[r2][4]=ADOQuery1->FieldByName("phone")->AsString;
    ADOQuery1->MoveBy(1);
    r2++;
    }
    int r3=1;

   ADOQuery1->Close();
   ADOQuery1->SQL->Clear();
   ADOQuery1->SQL->Add("select * from authors where state='"+aNode->Text+"' order by au_id");
   ADOQuery1->Open();


        while(!ADOQuery1->Eof){

             StringGrid1->Cells[1][r3] = ADOQuery1->FieldByName("au_id")->AsString;
             StringGrid1->Cells[2][r3] = ADOQuery1->FieldByName("au_lname")->AsString;
             StringGrid1->Cells[3][r3] = ADOQuery1->FieldByName("au_fname")->AsString;
             StringGrid1->Cells[4][r3] = ADOQuery1->FieldByName("phone")->AsString;
              ADOQuery1->MoveBy(1);
              r3++;
        }
        int r4=1;

       ADOQuery1->Close();
       ADOQuery1->SQL->Clear();
       ADOQuery1->SQL->Add("select * from authors where state='"+aNode->Text+"' order by au_lname");
       ADOQuery1->Open();


        while(! ADOQuery1->Eof){

             StringGrid2->Cells[1][r4] = ADOQuery1->FieldByName("au_lname")->AsString;
             StringGrid2->Cells[2][r4] = ADOQuery1->FieldByName("au_fname")->AsString;
             StringGrid2->Cells[3][r4] = ADOQuery1->FieldByName("au_id")->AsString;
             StringGrid2->Cells[4][r4] = ADOQuery1->FieldByName("phone")->AsString;
             ADOQuery1->MoveBy(1);
             r4++;
        }



}

uj5u.com熱心網友回復：

錯誤資訊呢？

uj5u.com熱心網友回復：

參考 1 樓 sirit 的回復:

錯誤資訊呢？

是可以運行，界面也出來了，但是TreeView沒有顯示任何資訊，然后點擊一下TreeView就提示
點擊確定之后，就指向上面紅色那行。。。。
求解釋

uj5u.com熱心網友回復：

TreeView沒有顯示任何資訊,

TTreeNode * aNode=TreeView1->Selected;

此時 aNode = NULL   再就是你哪一行  aNode->Text  當然參考了一個空指標  

轉載請註明出處，本文鏈接：https://www.uj5u.com/houduan/110069.html

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