ClientDataSet修改数据库并导入后再次修改会出错，怎么办？

Question

要看到ClientDataSet的具体语句，才能分析问题所在？

Answer 1

procedure TForm1.Button10Click(Sender: TObject);
var
  STr,Todata:string;
  Flag:Integer;
begin
  ClientDataSet1.Fields[7].ReadOnly:=False;
  ClientDataSet1.Fields[8].ReadOnly:=False;
  ClientDataSet1.Fields[10].ReadOnly:=False;
  ClientDataSet1.Fields[12].ReadOnly:=False;
  ClientDataSet1.Fields[14].ReadOnly:=False;
  Flag:=0;
  STr:='select * from Input where 变电站名= ''' + Edit1.Text + '''';
  ClientDataSet1.CommandText:=STr;
  ClientDataSet1.open;
  While not ClientDataSet1.Eof  do
  begin
      if ClientDataSet1.Fields[9].AsBoolean = True then
       begin
          if ClientDataSet1.Fields[8].Value = Null then
          begin
          Flag:=1;
          ClientDataSet1.Edit;
          ClientDataSet1.FieldByName('运维班核对人1').AsString:=loginForm.edit2.Text;
          ClientDataSet1.Post;
          end;
          if ClientDataSet1.Fields[8].Value = '' then
          begin
          Flag:=1;
          ClientDataSet1.Edit;
          ClientDataSet1.FieldByName('运维班核对人1').AsString:=loginForm.edit2.Text;
          ClientDataSet1.Post;
          end;
       end;
         if ClientDataSet1.Fields[9].AsBoolean = True then
         begin
         if ClientDataSet1.Fields[11].AsBoolean = True then
          begin
          if ClientDataSet1.Fields[12].Value = Null then
          begin
          Flag:=2;
          ClientDataSet1.Edit;
          ClientDataSet1.FieldByName('核对情况').AsString:='正常';
          ClientDataSet1.FieldByName('运维班核对人2').AsString:=loginForm.edit2.Text;
          ClientDataSet1.Post;
          end;
          if ClientDataSet1.Fields[12].Value = '' then
          begin
          Flag:=2;
          ClientDataSet1.Edit;
          ClientDataSet1.FieldByName('核对情况').AsString:='正常';
          ClientDataSet1.FieldByName('运维班核对人2').AsString:=loginForm.edit2.Text;
          ClientDataSet1.Post;
          end;
          end;
          if ClientDataSet1.Fields[13].AsBoolean = True then
          begin
          if ClientDataSet1.Fields[12].Value = Null then
            begin
              Flag:=2;
              ClientDataSet1.Edit;
              ClientDataSet1.FieldByName('监控核对人').AsString:=Edit6.Text;
              Todata:=datetostr(Date());
              ClientDataSet1.FieldByName('核对日期').AsString:=Todata;
              ClientDataSet1.Post;
            end;
            if ClientDataSet1.Fields[12].Value = ''  then
              begin
              Flag:=2;
              ClientDataSet1.Edit;
              ClientDataSet1.FieldByName('监控核对人').AsString:=Edit6.Text;
              Todata:=datetostr(Date());
              ClientDataSet1.FieldByName('核对日期').AsString:=Todata;
              ClientDataSet1.Post;
              end;
           end;
       end;
          if not ClientDataSet1.Fields[9].AsBoolean then
                begin
                 ClientDataSet1.Prior;
                 break;
                end;
          if Flag =2 then
            begin
            if  ClientDataSet1.Fields[11].AsBoolean then
                ClientDataSet1.Next;
            end;
            if Flag = 1 then
               ClientDataSet1.Next;
            if  Flag =2 then
              begin
              if not ClientDataSet1.Fields[11].AsBoolean then
                begin
                 ClientDataSet1.Prior;
                 break;
                end;
              end;
  end;
          ADOquery2.Close;
          ADOquery2.SQL.Clear;
          ADOquery2.SQL.Add('select * from Input where 变电站名= ''' + Edit1.Text + '''');
          ADOquery2.Open;
          with DataSetProvider1.DataSet.FieldByName( '序号' ) do
          ProviderFlags := ProviderFlags + [ pfInKey ];
          with DataSetProvider1.DataSet.FieldByName( '变电站名' ) do
          ProviderFlags := ProviderFlags + [ pfInKey ];
          ClientDataSet1.ApplyUpdates (0);
          ADOquery2.Close;
          ClientDataSet1.Fields[7].ReadOnly:=True;
          ClientDataSet1.Fields[8].ReadOnly:=True;
          ClientDataSet1.Fields[10].ReadOnly:=True;
          ClientDataSet1.Fields[12].ReadOnly:=True;
          ClientDataSet1.Fields[14].ReadOnly:=True;
end;

Answer 2

简单看了你的代码：
1、你的
  While not ClientDataSet1.Eof  do
  begin
  end; 
循环中，缺少有效的NEXT语句。在这种循环中，进入每一个 (行)数据后，不管如何处理数据，都要能进入下一行数据（NEXT），或退出。不能停留在某行，造成死循环。
2、你的Next出口，有以下：
Flag =0； Flag =1；Flag =2；  ClientDataSet1.Fields[11].AsBoolean=True；ClientDataSet1.Fields[11].AsBoolean=False
组合的情况；在  While not ClientDataSet1.Eof  do循环中，没有完全列举列举出来，造成了死循环。
3、你的NEXT出口，列举使用并列式的法语句不妥：
    if not ClientDataSet1.Fields[9].AsBoolean then
    begin
    end;
    if Flag =2 then
    begin
      if ClientDataSet1.Fields[11].AsBoolean then
    end;
    if Flag = 1 then
    if  Flag =2 then
    begin
      if not ClientDataSet1.Fields[11].AsBoolean then
      begin
      end;
    end;
这样，会有没有列举的情况，造成死循环，建议使用纯与否组合语句：
if   then begin
   if  then
      esle 
end
else begin
   if  then
      esle 
end;
与否执行的语句只能有二种;NEXT或  break;。 
4、循环中使用Prior;
只能二种情况：（1）退后一步，处理数据后，一定还要前进二步，切实保证Next；
 （2） 退后一步，处理数据后，退出循环。以上，仅供参考。