How to use Listview correctly in delphi? - delphi

Question

My code is the below, it's working correctly but, but after compiling program i see all the fullname and country listed vertically something like :
_________________________________
Fullname1
Country1
Fullname2
Country2
Fullname3
Country3
etc...
SQLQuery1.SQL.Text := 'SELECT * FROM users where user_age="'+age+'"';
SQLQuery1.Open;
rec := SQLQuery1.RecordCount;
SQLQuery1.First; // move to the first record
ListView1.Visible := false;
if rec>0 then
begin
while(not SQLQuery1.EOF)do begin
ListView1.Visible := true;
// do something with the current item
ListView1.AddItem('Full name: '+SQLQuery1['fullname'], Self);
ListView1.AddItem('Country: '+SQLQuery1['cntry'], Self);
// move to the next record
SQLQuery1.Next;
end;
But i want something Like :

Answer 1

First: add the column headers:
var
Col: TListColumn;
begin
Col := ListView1.Columns.Add;
Col.Caption := 'Name';
Col.Alignment := taLeftJustify;
Col.Width := 140;
Col := ListView1.Columns.Add;
Col.Caption := 'Country';
Col.Alignment := taLeftJustify;
Col.Width := 140;
end;
then add the records as follows:
var
Itm: TListItem;
begin
// start of your query loop
Itm := ListView1.Items.Add;
Itm.Caption := SQLQuery1['fullname'];
Itm.SubItems.Add(SQLQuery1['cntry']);
// end of your query loop
end;
Update:
Of course, in order to get the list as in your screenshot, you need to set the ListView's ViewStyle property to vsReport

Answer 2

Your code should look like that:
var
ListItem: TListItem;
...
ListView.Items.BeginUpdate;
try
while(not SQLQuery1.EOF)do begin
ListItem:= ListView.Items.Add;
ListItem.Caption:= 'Full name: '+SQLQuery1['fullname'];
with ListItem.SubItems do begin
Add('Country: '+SQLQuery1['cntry']);
// if you need more columns, add here
end;
SQLQuery1.Next;
end;
finally
ListView.Items.EndUpdate;
end;
You should also set ListView.Style to vsReport to show listview as grid.

Answer 3

I'm not sure how to get the listview to multiline, but I do know you're not using the Query correctly.
As it stands your code has an SQL-injection hole and the implicit reference to 'fieldbyname' inside the loop makes it slow.
var
FullName: TField;
Country: TField;
ListItem: TListItem;
begin
//Use Params or suffer SQL-injections
SQLQuery1.SQL.Text := 'SELECT * FROM users where user_age= :age';
SQLQuery1.ParamByName('age').AsInteger:= age;
SQLQuery1.Open;
if SQLQuery1.RecordCount = 0 then Exit;
//Never use `FieldByName` inside a loop, it's slow.
FullName:= SQLQuery1.FieldByName('fullname');
Country:= SQLQuery1.FieldByName('cntry');
ListView1.Style:= vsReport;
SQLQuery1.First; // move to the first record
SQLQuery1.DisableControls; //Disable UI updating until where done.
try
ListView1.Items.BeginUpdate;
//ListView1.Visible := false;
while (not SQLQuery1.EOF) do begin
//Code borrowed from #Serg
ListItem:= ListView.Items.Add;
ListItem.Caption:= 'Full name: '+Fullname.AsString;
ListItem.SubItems.Add('Country: '+Country.AsString);
SQLQuery1.Next;
end; {while}
finally
SQLQuery1.EnableControls;
ListView1.Items.EndUpdate;
end;
end;

Answer 4

The Delphi documentation contains this example that does exactly what you want.
procedure TForm1.FormCreate(Sender: TObject);
const
Names: array[0..5, 0..1] of string = (
('Rubble', 'Barney'),
('Michael', 'Johnson'),
('Bunny', 'Bugs'),
('Silver', 'HiHo'),
('Simpson', 'Bart'),
('Squirrel', 'Rocky')
);
var
I: Integer;
NewColumn: TListColumn;
ListItem: TListItem;
ListView: TListView;
begin
ListView := TListView.Create(Self);
with ListView do
begin
Parent := Self;
Align := alClient;
ViewStyle := vsReport;
NewColumn := Columns.Add;
NewColumn.Caption := 'Last';
NewColumn := Columns.Add;
NewColumn.Caption := 'First';
for I := Low(Names) to High(Names) do
begin
ListItem := Items.Add;
ListItem.Caption := Names[I][0];
ListItem.SubItems.Add(Names[I][2]);
end;
end;
end;
For all that the Delphi documentation is much maligned, it often has very useful examples like this. The gateway page to the examples is here and the examples are even available on sourceforge so you can check them out using your favourite svn client.

Answer 5

Procedure TForm1.GetUsers;
var
ListItem: TListItem;
begin
try
ListView1.Items.BeginUpdate;
try
ListView1.Clear;
MySQLQuery.SQL.Clear;
MySQLQuery.SQL.Add('select * from users;');
MySQLQuery.Open;
while (not MySQLQuery.EOF) do
begin
ListItem := ListView1.Items.Add;
ListItem.Caption:= VarToSTr(MySQLQuery['username']);
with ListItem.SubItems do
begin
Add(VarToSTr(MySQLQuery['password']));
Add(VarToSTr(MySQLQuery['maxscore']));
end;
MySQLQuery.Next;
end;
MySQLQuery.Close;
finally
ListView1.Items.EndUpdate;
end;
except
on E: Exception do
MessageDlg(PWideChar(E.Message), TMsgDlgType.mtError, [TMsgDlgBtn.mbOK], 0);
end;
end;