急，问题有点莫明其妙，花了三天去分析原因，都搞不清楚！MDIChild窗体中DBGrid无法响应！分不够可以再加！

Question

详细情况：
  一个主窗体和一个MDIChild窗体.
  在主窗体左边有一个treeview控件，它会在主窗体初始化时会自动加载资料！
  MDIChild窗体中在很多Edit控件和一个DBGrid窗件！
  点击TreeView控件中某一个特定选项A后，调用出MDIChild窗体.MDIChild窗体中DBGrid控件会显示相应的数据。
  好到为此，还正常。
  
  问题就是：再点击主窗体中TreeView控件任意地方后，再直接点击MDIChild窗体中DBGrid控件，DBGrid控件没有任何反映，
  那解决这个问题，只先点击MDIChild窗体其它控件后，才能点击DBGrid控件！  为什么会这样，以前不会这样啊！我以为是TreeView控件中点击事件有问题,但是我取消点击事件后，同出现上面的问题！

Answer 1

点击TreeView控件中某一个特定选项A后，调用出MDIChild窗体.MDIChild窗体中DBGrid控件会显示相应的数据。把这段代码贴出来看看

Answer 2

procedure TMainForm.MainTreeViewDblClick(Sender: TObject);
var
  i:integer;
  SQLString:string;
begin
  if MainTreeView.Selected=nil then exit;
  if MainTreeView.Selected.Level=0 then
    begin
       if Trim(MainTreeView.Selected.Text)='业务受理' then
         begin
            Current_YWBH:='';
            application.CreateForm(TFrmSelectYWSQ,FrmSelectYWSQ);
            FrmSelectYWSQ.ShowModal;
            if YW_FormClass<>nil then
              begin
                 HJ_FormClass:=TFrmHJ_SQ;
                 HJ_Form:=FrmHJ_SQ;
                 Current_SQBH:='';
                 if YW_FormClass=TFormYHXZ then
                   openform(TFormYHXZ,FormYHXZ,self,true)
              end
            else begin
                HJ_FormClass:=nil;
                HJ_Form:=nil;
                HJ_FormClass:=nil;
                HJ_Form:=nil;
                Current_HJBH:='';
                Current_SQBH:='';
                Current_YWBH:='';
            end;
         end;
    end
  else if MainTreeView.Selected.Level=1 then
    begin
       OpenForm(TFrmYWLL,FrmYWLL,self,true);
       if Trim(MainTreeView.Selected.Parent.Text)='日常营业' then
         begin
            FrmYWLL.ADOQuery_YWLL.Close;
            for i:=1 to 16 do
              if POS(L_YWMC[i],Trim(MainTreeView.Selected.Text))>0 then
                begin
                   with FrmYWLL.ADOQuery_YWLL do
                     begin
                        close;
                        sql.Clear;
                        SQLString:='Select YK_YWSQSLB.SQBH,YK_YWSQSLB.LB,YK_ZD_YWDY.DES as YWMC,YK_YWSQSLB.YDBH,YK_YWSQSLB.ZXXH,YK_YWSQSLB.HJBH,YK_ZD_HJDY.DES as HJMC,'
                                  +'case when YK_YWSQSLB.ZXZK=''0'' then ''待处理'' when YK_YWSQSLB.ZXZK=''1'' then ''已处理通过'' when YK_YWSQSLB.ZXZK=''2'' then ''未通过退回'' end as ZXZK ,'
                                  +'case when YK_YWSQSLB.WCBZ=''0'' then ''申请'' when YK_YWSQSLB.WCBZ=''1'' then ''正常执行'' when YK_YWSQSLB.WCBZ=''2'' then ''被追回'' when YK_YWSQSLB.WCBZ=''3'' then ''执行完'' end as WCBZ'
                                  +' ,YK_YWSQSLB.CLSJ,YK_YWSQSLB.RYBH,YK_YWSQSLB.MS '
                                  +' from YK_YWSQSLB,YK_ZD_YWDY,YK_ZD_HJDY where  YK_YWSQSLB.LB=YK_ZD_YWDY.ID and YK_YWSQSLB.HJBH=YK_ZD_HJDY.ID and YK_ZD_YWDY.DES like '''+'%'+L_YWMC[i]+'%'+''' order by YK_YWSQSLB.SQBH,YK_YWSQSLB.ZXXH ';
                        sql.Add(SQLString);
                        open;
                     end;
                   YW_HJInitTreeView(i);                   break;
                end;//判断是内容是什么业务
            FrmYWLL.RadioButton1.SetFocus;
         end//判断这第二级是日常营业下
       else if Trim(MainTreeView.Selected.Parent.Text)='环节处理' then begin
           FrmYWLL.ADOQuery_YWLL.Close;
            for i:=1 to 12 do
              if POS(L_HJMC[i],Trim(MainTreeView.Selected.Text))>0 then
                begin
                   with FrmYWLL.ADOQuery_YWLL do
                     begin
                        close;
                        sql.Clear;
                        SQLString:='Select YK_YWSQSLB.SQBH,YK_YWSQSLB.LB,YK_ZD_YWDY.DES as YWMC,YK_YWSQSLB.YDBH,YK_YWSQSLB.ZXXH,YK_YWSQSLB.HJBH,YK_ZD_HJDY.DES as HJMC,'
                                  +'case when YK_YWSQSLB.ZXZK=''0'' then ''待处理'' when YK_YWSQSLB.ZXZK=''1'' then ''已处理通过'' when YK_YWSQSLB.ZXZK=''2'' then ''未通过退回'' end as ZXZK ,'
                                  +'case when YK_YWSQSLB.WCBZ=''0'' then ''申请'' when YK_YWSQSLB.WCBZ=''1'' then ''正常执行'' when YK_YWSQSLB.WCBZ=''2'' then ''被追回'' when YK_YWSQSLB.WCBZ=''3'' then ''执行完'' end as WCBZ'
                                  +' ,YK_YWSQSLB.CLSJ,YK_YWSQSLB.RYBH,YK_YWSQSLB.MS '
                                  +' from YK_YWSQSLB,YK_ZD_YWDY,YK_ZD_HJDY where  YK_YWSQSLB.LB=YK_ZD_YWDY.ID and YK_YWSQSLB.HJBH=YK_ZD_HJDY.ID and YK_ZD_YWDY.DES like '''+'%'+L_YWMC[i]+'%'+''' order by YK_YWSQSLB.SQBH,YK_YWSQSLB.ZXXH ';
                        sql.Add(SQLString);
                        open;
                     end;                   break;
                end;//判断是内容是什么业务
            FrmYWLL.RadioButton1.SetFocus;
       end;
    end;//是第二级

Answer 3

myling(阿德) :
  
   我也在别的机子上做了同样的例子，主窗体初始化时treeview控件只加载一些数据。MDIChild窗体初始化时自动为DBGrid程序加载数据（ADOQuery控件Active为True,与DBGrid、datasource三个控件互联）。简化到两个窗体没有点击事件的关连！
同样出现问题！
  
  还有一点运行以前没有这个问题的程序（已经做好了的），直接运行程序，也出现了这个问题！