cds.CreateDataSet;
cds.Close;
lf_Field := TField.Create(cds);
lf_Field.FieldName :='计算列';
lf_Field.DataSet := cds;
lf_Field.FieldKind := fkCalculated;
lf_Field.Index:=cds.FieldCount;
cds.FieldDefs.Update;
老提示'Field cannot be a calculated or lookup field'错误,真没办法
cds.Close;
lf_Field := TField.Create(cds);
lf_Field.FieldName :='计算列';
lf_Field.DataSet := cds;
lf_Field.FieldKind := fkCalculated;
lf_Field.Index:=cds.FieldCount;
cds.FieldDefs.Update;
老提示'Field cannot be a calculated or lookup field'错误,真没办法
以前CSDN上有好多人问过这个问题,但是好象没有人给出满意的答案。
我也是经过好长时间摸索才找到答案,现在在这给大家分享:
procedure TForm1.FormCreate(Sender: TObject);
var
NewField:TField;
i:integer;
begin
//表中有两字段SName,Birth,现在我们动态生成一个计算字段Age,显示出年龄
NewField:=TStringField.Create(ADOTable);
//创建一个TStringField类型的字段
ADOTable.Close;
for i:=0 to ADOTable.Fields.Count-1 do
ADOTable.Fields[0].Free;//释放所有的静态字段
for i:=0 to ADOTable.FieldDefs.Count-1 do
ADOTable.FieldDefs.Items[i].CreateField(ADOTable);
//根据FieldDefs的字段信息动态的生成静态字段
NewField.Size:=5;
NewField.FieldName:=''''Age'''';
NewField.FieldKind:=fkCalculated;
//设置这个这字段为计算字段
NewField.DataSet:=ADOTable;
//把这个字段加到ADOTable上
ADOTable.Open;
end; procedure TForm1.ADOTableCalcFields(DataSet: TDataSet);
var
YY1,YY2,MM,DD:Word;
TmpDate:TDate;
begin
DecodeDate(Date,YY1,MM,DD);
TmpDate:=DataSet.FieldByName(''''Birth'''').AsDateTime;
DecodeDate(TmpDate,YY2,MM,DD);
DataSet.FieldByName(''''Age'''').AsString:=IntToStr(YY1-YY2) ''''岁'''';
//在OnCalField中显示出年龄
end;
参考资料:http://west263.com/info/html/chengxusheji/delphi/20080411/63509.html