CODEWITHSUNDEEP
databasedelphilistboxdelphi-7
avue
avue

Reputation: 129

Tlistbox items from database column

Is there a way to populate a TListbox control with items from a database column?

I know the proper way to do this is to simply use a DBLookupListbox control and set it up to access the column I want, but the problem with that is when I click on one of the items in the lookup control, it changes the current row in the dataset (expected behavior) but I do not want this to happen.

Instead, I would want the current row to be changed only on a double click event in the lookup control and since I do not think this behavior is possible to change, I thought it would be easier to simply use a normal TListBox instead, but as I stated above, I am not sure how it's done.

So once again, I have come to the experts for some advise on how to populate a normal Tlistbox control with items from a database column.

Upvotes: 1

Views: 4623

Answers (3)

RRUZ
RRUZ

Reputation: 136391

You don't specify DB the components which you are using, so I wrote this sample using ADO and MySQL.

const
StrConnection='Driver={MySQL ODBC 5.1 Driver};Server=%s;Database=%s;User=%s; Password=%s;Option=3;';

procedure LoadColumn(Items:TStrings; const SqlStr :string);
Var
 AdoDataSet : TADODataSet;
begin
 AdoDataSet:=TADODataSet.Create(nil);
 try
  //you can share the connection too, in this case a new connection is made
  AdoDataSet.ConnectionString:=Format(StrConnection,['server','mydatabase','user','pass']);;
  AdoDataSet.CommandText:=SqlStr;
  AdoDataSet.Open;
  if not AdoDataSet.IsEmpty then
  begin
    Items.BeginUpdate;
    try
     Items.Clear;
     while not AdoDataSet.Eof do
     begin
       Items.Add(AdoDataSet.Fields[0].AsString);
       AdoDataSet.Next;
     end;
    finally
     Items.EndUpdate;
    end;
  end;
 finally
   AdoDataSet.Free;
 end;
end;

And use like so

   LoadColumn(ListBox1.Items, 'Select MyColumn FROM Table');

Upvotes: 4

John Easley
John Easley

Reputation: 1570

There are a myriad of ways to solve your problem. You could create a hacked control of a TDbLookupListBox and override the Click method to do nothing. You could also create a second dataset to be used for your lookup. But as you wish, to populate a TListbox, you simply iterate the dataset and add the field value to the listbox as:

tLogin.first;
while not tLogin.eof do
begin
  Listbox1.Items.Add(tLogin.fieldbyname('fullname').asstring);
  tLogin.next;
end;

If you need a key value based on a selection, then this won't solve your problem entirely. You'd be better off hacking the TDbLookupListbox control, imo.

Upvotes: 2

NGLN
NGLN

Reputation: 43649

Use a TDBLookupListBox. Use the ListField property and ignore the DataField property.

Upvotes: 1

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