用ClientDataSet和dbgrid 如何通过点击dbgrid的标题进行排序

Question

用ClientDataSet和dbgrid 如何通过点击dbgrid的标题进行排序

Answer 1

用DbgridEh很方便,基本上是0代码实现

Answer 2

查ClientDataSet帮助AddIndex的使用

Answer 3

在Form里添加两个public变量
    Fdns,descs:string;编写DBGrid的OnTitleClick事件
procedure TForm1.GridOnTitleClick(Column: TColumn);
var fdn,disp,flag,ins1:string;
function GetIndexName:string;
var s1:string;
begin
  s1:='I'+DateTimeToStr(Now)+IntToStr(Random(999));
  s1:=AnsiReplaceText(s1,' ','');
  s1:=AnsiReplaceText(s1,'_','');
  s1:=AnsiReplaceText(s1,':','');
  Result:=s1;
end;
begin
 { if Column.Index>ClientDataSet1.Fields.Count-1 then
  begin
    showmessage('不成'+IntToStr(Column.Index)+','+IntToStr(ClientDataSet1.Fields.Count));
    exit;
  end; }
  if not DBGrid1.DataSource.DataSet.Active then
  begin
    ShowMessage('没有打开'+DBGrid1.DataSource.DataSet.Name);
    exit;
  end;
  if DBGrid1.DataSource.DataSet.RecordCount=0 then exit;
  if ClientDataSet1.IndexDefs.Count>0 then  fdns:=ClientDataSet1.IndexDefs.Items[ClientDataSet1.IndexDefs.Count-1].Fields;
  if ClientDataSet1.IndexDefs.Count>0 then  descs:=ClientDataSet1.IndexDefs.Items[ClientDataSet1.IndexDefs.Count-1].DescFields;
  fdn:=ClientDataSet1.Fields[Column.Index].FieldName;
  disp:=ClientDataSet1.Fields[Column.Index].DisplayLabel;
  if pos('↓',disp)>0 then
  begin
    flag:='↑';//如果正续排列
    if pos(fdn,fdns)=0 then fdns:=fdns+';'+fdn;//如果没有正序,则添加
    if pos(fdn,descs)=0 then descs:=descs+';'+fdn;//增加反序  end
  else if pos('↑',disp)>0 then
  begin
   flag:='';//如果无序
   fdns:=AnsiReplaceText(fdns,fdn,'');
   descs:=AnsiReplaceText(descs,fdn,'');
  end
  else
  begin
    flag:='↓';//如果反序
    if pos(fdn,fdns)=0 then fdns:=fdns+';'+fdn;//增加索引
    if pos(fdn,descs)=0 then descs:=AnsiReplaceText(descs,fdn,'');//去除反续
  end;
  fdns:=AnsiReplaceText(fdns,' ','');
  while pos(';;',fdns)>0 do fdns:=AnsiReplaceText(fdns,';;',';');
  if copy(fdns,1,1)=';' then delete(fdns,1,1);
  if copy(fdns,length(fdns),1)=';' then delete(fdns,length(fdns),1);
  descs:=AnsiReplaceText(descs,' ','');
  while pos(';;',descs)>0 do descs:=AnsiReplaceText(descs,';',';');
  if copy(descs,1,1)=';' then delete(descs,1,1);
  if copy(descs,length(descs),1)=';' then delete(descs,length(descs),1);
  disp:=flag+fdn;  ClientDataSet1.DisableControls;
  ins1:=GetIndexName;
  while  ClientDataSet1.IndexDefs.Count>0  do  ClientDataSet1.DeleteIndex(ClientDataSet1.IndexDefs.Items[0].Name);
  ClientDataSet1.IndexName:='';
  ClientDataSet1.AddIndex(ins1,fdns,[ixCaseInsensitive],descs,'',0);  ClientDataSet1.IndexName:=ins1;
  ClientDataSet1.Fields[Column.Index].DisplayLabel:=flag+fdn;
  ClientDataSet1.First;
  ClientDataSet1.EnableControls;
end;