How can I access which checkbox was changed/clicked in an unblund column and get its value (true/false)?

Klemen Hrovat

created 8 years ago

[DevExpress Support Team: CLONED FROM A1095: How to set up an unbound item in a data-aware View]
Hi,

How can I then access which checkbox was changed/clicked and its value (true/false)?

Regards

Answers approved by DevExpress Support

DevExpress Support Team

created 8 years ago (modified 8 years ago)

Hello Klemen,

When you click a checkbox in GridView, the record and column, where the editor is located, become focused. So, you can work with the focused record and column to determine where an in-place checkbox has been changed:

Delphi
var  
  AValue: Boolean;  
begin  
  with <AcxGridDBTableView>.DataController do  
    AValue := Values[FocusedRecordIndex, <AUnboundColumnWithCheckBox>.Index];

Show previous comments (3)

Klemen Hrovat 8 years ago

Well I still have a problem how to make chekboxes "checked". I get aUniqueField values from database but I cannot check specific checkbox in column colUnbound. I'm attaching you my example. Thank you.

example.txt

Klemen Hrovat 8 years ago

By the way I want to check them in run time.

DevExpress Support Team 8 years ago

Klemen, thank you for the code. I checked it and would like to comment on certain points.
Could you please clarify where you adjust a View like it is shown in the A1095 KB article? An unbound column is a column that has no assigned DataSet Field. So, you need to work with column values at the View level, but not at the DataSet one.
To accomplish this task, I suggest you do the following:

Adjust your GridView in the same manner as it is described in the A1095 KB article:
A) Set DataController's DataModeController.SmartRefresh property to True.
B) Initialize the Data Controller's KeyFieldNames property.
2) Add a new column to the View. Do not initialize its DataBinding.FieldName property.
Use the DataController.Values method to set values to the unbound column.

Here is a code sample showing this approach:

Delphi
procedure <AForm>.FormCreate(Sender: TObject);  
var  
  AUnboundColumn: TcxGridDBColumn;  
  I: Integer;  
  AValue: Boolean;  
begin  
  ...  
  <AcxGridDBTableView>.DataController.DataModeController.GridMode := False;  
  <AcxGridDBTableView>.DataController.DataModeController.SmartRefresh := True;  
  <AcxGridDBTableView>.DataController.KeyFieldNames := <AKeyField>;  // Set the Key Field with unique values  

  AUnboundColumn := <AcxGridDBTableView>.CreateColumn;  
  with AUnboundColumn do  
  begin  
    Name := <AName>;  
    Caption := <ACaption>;  
  end;  
  AUnboundColumn.DataBinding.ValueTypeClass := TcxBooleanValueType;  
  AUnboundColumn.PropertiesClass := TcxCheckBoxProperties;  

  for I := 0 to <AcxGridDBTableView>.DataController.RecordCount - 1 do  
  begin  
    AValue := Odd(I);     // Set True to records with odd RecordIndex  
    <AcxGridDBTableView>.DataController.Values[I, AUnboundColumn.Index] := AValue;  
  end;  
  ...  
end;

Klemen Hrovat 8 years ago

Thank you Mikhail.

This works now:

Delphi
cxGrid1DBTableView1.DataController.CreateAllItems;  
cxGrid1DBTableView1.ApplyBestFit;  

i := 0;  
GDataModule.CdsKandidatiSolaRok.First;  
while (not GDataModule.CdsKandidatiSolaRok.EOF) do  
begin  

AValue := GDataModule.CdsKandidatiSolaRok.FieldByName('aUniqueField').AsBoolean;  
cxGrid1DBTableView1.DataController.Values[i, AUnboundColumn.Index] := AValue;  

inc(i);  
GDataModule.CdsKandidatiSolaRok.Next;  
end;

I was creating all grid items after I set AUnboundColumn. Instead I had to make it before. So it was always empty…

Klemen Hrovat 8 years ago

I have one more question regarding cxGrid checkboxes. I have difficulties capturing onClick event for checkbox. I want to check in event if checkbox is "checked" or "unchecked". I'm trying in onCellClick event from cxGrid but without luck. I only managed to check if cell is checkbox. Can you please help me?

Some events code example:

Delphi
procedure TFrmLastenFilter.GridKandidatiTV1CellClick(Sender: TcxCustomGridTableView;  
  ACellViewInfo: TcxGridTableDataCellViewInfo; AButton: TMouseButton; AShift: TShiftState; var AHandled: Boolean);  
begin  
  with ACellViewInfo do  
    if Properties is TcxCheckBoxProperties then  
    begin  
      // Here is your code  
      showmessage('Is checkbox');  

      if GridKandidatiTV1.DataController.Values[GridKandidatiTV1.DataController.FocusedRowIndex, 0] = true then // CB checked  
      begin  
        showmessage('checked');  
      end  
      else  
        if GridKandidatiTV1.DataController.Values[GridKandidatiTV1.DataController.FocusedRowIndex, 0] = False then // CB unchecked  
        begin  
          showmessage('unchecked');  
        end;  
    end  
    else  
      showmessage('Not checkbox');  
end;

Regards

DevExpress Support Team 8 years ago

I recommend you take a look at the B20752: OnCellDblClick/OnCellClick events aren't fired for a CheckBox column to learn why the OnCellClick event is not triggered for cells with CheckBoxes by default. There you can find a workaround for this behavior.
Also, you can use the OnEditValueChanged event to accomplish the task:

Delphi
procedure <AForm>.<ACheckBoxColumn>PropertiesEditValueChanged(Sender: TObject);  
begin  
  Caption := 'CheckBox.Checked = ' + BoolToStr(TcxCheckBox(Sender).EditValue, True);  
end;

Created: September 7, 2017 12:19 PM

Modified: September 14, 2017 11:13 AM

Platform: VCL

Product: ExpressQuantumGrid Suite

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How can I access which checkbox was changed/clicked in an unblund column and get its value (true/false)?

Answers approved by DevExpress Support

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